NEWS:

03-18-07  Sherri's stepfather passed away about a month ago. Sherri's had to go stay with her mother to help her deal with all of the associated issues. She has been gone for 4 weeks, and will not be back for at least two more weeks. This has left me to deal with all of the things that she usually handles. Those in the USA know what time of year this is. Personal income taxes (ours and my mothers), corporate (Tubelab and G&S programming) taxes, and corporate annual reports all must be done. I have less than two weeks left to complete them, and I am not done yet. There has been no activity related to Tubelab in the last month.

   Sherri's mother had relied on her husband to handle all of her finances for the past 20 years. She had not touched a checkbook in 20 years, and had no knowledge of insurance policies, retirement accounts, house and auto ownership deeds etc. These things are real hard to figure out after after the fact. This experience has let me see just how much I have relied on Sherri to handle all things financial. Fortunately she is still a phone call away. If this describes your situation (or your parents) do all you can to learn about this stuff before something happens.

 01-22-07  My new computer is finally operational, and most of my applications and data have been migrated. Microsoft  has decided not to offer anymore upgrades to the Front Page software that I have been using to make this web site. They now offer Microsoft Expression Web as the upgrade path. I purchased Expression Web and loaded on my computer.  I tried to use it on my web site. It doesn't work with my site.  Expression does not support the navigation structure built by Front Page, and tells me that my Web site was not built to current web standards. I bought a couple of books, and decided that this is not going to be easy. I am still using Front Page for now.

    I have been on the road for almost every weekend so far this year. Most of this web update was written from the passenger seat of a car on my laptop. Some pages are still incomplete, but I decided to post what I have since it has been a while since the last update. Most of the Simple SE manual is complete, except for the wiring diagrams, parts list with vendor part numbers since I don't have internet access in my car, and the assembly pictures of my latest amps, since I haven't been home to take the pictures. I built (and documented) the Industrial amp shown above in December, and haven't had time to listen to it since then. I haven't touched a soldering iron yet this year either.

   I have not yet figured out how to set up an internet shopping cart on my web page. It must be set up interactively on the server, and again, I have not been home to figure it out. I plan to begin listing the PC boards on Ebay as soon as the parts lists and wiring diagrams are complete. If my current work schedule does not change, this should be in a couple of weeks. My Ebay ID is Tubelab*com.  There is nothing posted there currently.

   I have fallen far behind in answering email. I thought that I could catch up over the holidays, but my planned two week vacation turned into 6 days off from work. I spent one to two hours per day answering email. During this time I received more email that I answered. I still have several hundred emails in my in box, and 5 or 10 come in each day. I have come to the realization that I may never catch up. All email from purchasers of my boards has been answered promptly. Much of the other email concerns PowerDrive. The PowerDrive cookbook page is not finished yet, but I have posted the first part. More email concerns the availability of the PC boards. They will be available shortly, and the ordering info will be posted here.  Email that requires considerable time, like those asking me to design a special circuit, or modify or test an amplifier that I have never seen often does not get answered. I simply don't have the time to design one off circuits until I get caught up. 

   Many questions (e-mail and diyAudio forum) relate to the PC boards. I get questions that ask about the "SE board". I have no way of knowing which board you are referring to, since there are now two different SE boards. I have also received questions asking how to wire a DHT into the Simple SE board and vice versa. This is not really practical. Each board was designed and optimized for the type of tubes listed in the assembly manual. I simply do not currently have the time to assist with a custom design or application for these designs.

   The most popular questions are," Where can I get a board" and "When can I get a board".  I plan to offer the boards directly from an online ordering page on this web site. I have that option on my current hosting plan. I may also offer them from an Ebay store. I will do this as soon as the assembly manual is finished. Most of the manual is finished (all of the fun amp building stuff). I need to finish processing about 200 pictures and organizing all of the text. I have about 3 weeks worth of work at my present rate, but I can not predict the demands of my full time job, which have been considerable, and require 8 to 10 hours of sitting in front of a computer per day.

   The progress will be posted here on this page, and ordering information will be posted here as well.

 11-28-06 It has been over 1 month since I ordered my new PC. It is still in pieces, occupying my workbench. I returned the defective memory, but have not received the replacements. Two of the three shiny new PC boards shown above are impatiently awaiting assembly into amplifiers, but I have no bench space. The middle board already has a happy home in a new amplifier. I have not been here much anyway.

   Last Thursday was the Thanksgiving holiday here in the USA. Traditionally it is spent with family. I drove to Tampa to celebrate Thanksgiving with my mom and brothers. The Friday after Thanksgiving has evolved into a major shopping event with half of America going to the shopping malls. This is a tradition that I do not choose to support, so I dropped Sherri and friends off at a mall near Orlando. A friend and I went to Daytona for the Turkey Rod Run. A 5 day celebration of all things automotive, where I spent 5 hours before going back to Orlando to pick up Sherri, and return to Ft Lauderdale. A page full of pictures has been added to the automotive pages.

  Saturday and Sunday was spent working on the Simple SE assembly manual, and updating this web site. I have added more of the assembly manual, with more to come after it has been proof read by a few others.

  Monday I returned to work, and was rewarded with another "must be done before years end" project. This means more days like today, 11 hours in front of a computer.

   11-14-06 My father would have been 85 today. My 5 year old PC has been acting erratic for the past year. I decided that It would be wiser to replace it than to keep repairing it. I usually build my own PC's but I decided that I would order a custom built PC to save time. I chose a Core 2 Duo computer from a company that has a 3 or 4 page ad in several major computer magazines. They offered a special deal featuring next day shipment and a fat discount, so I ordered one. It two weeks to get the computer and it wasn't configured as I ordered. I then spent almost 2 days loading it up with all of my applications, and copying almost 100GB of data on to it. As I loaded software on to it, it became more and more unstable. After 2 more days it became totally unusable. At first my e-mail and phone calls went unanswered or not returned, or I got responses like "you shouldn't be using 64 bit Windows". They sold it to me! I asked twice for an RMA # to return the whole PC. Then I finally got to e-mail a tech. By this time my whole workbench is covered in dismantled PC and software. It has been almost a month since I placed the order, and I finally have figured it out (with some help from their techie). It seems that the machine will pass a complex suite of memory test software (the one on the Suse 9.3 distribution CD) for 6 hours with 0 errors, but the system memory is schizophrenic with 64 bit Windows, stupid with 32 bit Windows, and just plain dead with Suse Linux. Two memory SIMMS from a local store and the machine is happy, and awesomely fast too. Now I get to load the software all over again. Maybe I will have my workbench back in a few days. I think this could have happened if I built my own machine as well, but I have built a lot of PC's (50 to 100) in the last 20 years, and I have never seen memory that passes a complex test suite, but fails in normal use.

   I am posting this update from my laptop.

    11-11-06 I have added the schematic for the entire Simple SE amp.

   11-09-06 I have uploaded parts of the Simple SE manual. Pages that I have had the time to finish, proof read, and have an associate use to assemble a board are posted. Much of it was written on my laptop in the passenger seat of a car. I have been away for 5 of the last 6 weekends. I will be away for the next two weekends also. I plan to finish most of the manual during the traveling time. If all goes well the shopping cart will go live during the last week of November.

   Because I wrote most of the assembly manual while traveling, there are probably errors that we didn't catch. If there are any, please e-mail me and I will fix them. I have fixed the ones that I received e-mail about (mostly wrong pictures). Please e-mail me if anything is not clearly understandable.

   10-26-06 It has been about two months since I last updated this web site. A lot has happened since then, and I have not had time to update this web site. I should have known what was waiting for me after almost a month off of work. I have been working a lot of hours since my return. Most of my time away from work has been spent on the Simple SE assembly manual. It is nearly done.

   I received about 1000 e-mails while I was away. Unfortunately some spam artists have acquired my e-mail address and filled my mailbox with offers of sex pills and penny stocks. This caused my email box to fill up (twice) and some e-mails may have been lost. E-mail that gets caught by the spam box still counts against my quota until I empty the box. If you e-mailed me in late August or September and never got a reply, your e-mail may have been lost. Please send it again. I try to answer all serious e-mail. E-mail from customers with questions get priority, everything else gets answered in order of receipt. I am currently about two weeks behind answering e-mail. My current work schedule only allows me time to answer e-mail on weekends.

08-15-06 I am posting this minor update (from a hotel room with free internet) to add the pictures from the 2006 Mopar Nationals including an entire page of pictures of the 2008 Dodge Challenger concept car. It was announced that production of this car will commence in April of 2008. I have done some minor reorganization of the site to make room for more pages in the future. Everything is still here, although some pages (and their links) now have their own sub page. I have been working on the assembly manual for the Simple SE amplifier. My return (and the manual) has been delayed by car trouble. Try to find an oil pan for a Volvo in rural West Virginia.

  The break in my work schedule lasted for 7 days (I knew that it was too good to be true). The Simple SE boards are in and three amps are already up and running. I can build these boards in about 45 minutes each, they go together real easy. I am already working on the construction manual. I have gathered about 500 pounds of transformers which will all be tested and the results posted here (two transformers are already done). I will be out of town for most of August, so there will not be much activity until September.

  I finally got a break from my relentless work schedule (it won't last) so I have been updating the web site every night. I have added (or finished) several pages in the Tech Pages and Tested and Proven Circuits sections. These pages were created to explain some of the experiments that began as a thread on the diyAudio forums. Some of the material is directly cut from my contributions to those threads. Some additional material has been added.

   The Simple SE section has been updated, and will continue to be updated as more info becomes available. The PC boards are on order. My amp has been stressed tested in several ways, including me playing guitar through it, and plugging it into a Variac and cranking the input voltage to 135 volts while playing rock music at full volume! It is still going strong.

   I have added some text and old pictures to the Tubelab SE assembly manual. I sold every assembled board that I had during the time that I was too busy to build any (the past 4 months). The pictures (text too) for the checkout and bias adjustment pages were lost last year. I have finished assembling a new board, and the new pictures will be shot this weekend. I will add them to the site ASAP.

 06-10-06  I have added a few more updates and 2 new pages (in a big hurry, so I am sure I messed something up). The Budget SE output transformers and the 6AV5 testing page. I have updated the Tubelab SE assembly manual, but I won't have it finished for a few more weeks. Many of the final assembly and checkout pages were lost, and the board that I used to shoot all of the pictures was sold a few months ago. I have assembled a new board, and am in the process of shooting new pictures.

  Tropical storm Alberto has reminded me that I must fix my roof before we get a serious storm. My roof got minor damage last year from hurricane Wilma. All of the roofing companies are booked selling complete re-roof jobs (15,000 to 45,000 dollars!). I can't get anyone to do my "small repair"( $1000), so I must do it myself.

06-04-06  With the last update I added a page of information about my Simple SE amplifier, The email and forum activity related to that project have been outstanding, so I have began a major expansion of that page. The one page is now 4, and more are coming. Some of these pages are not complete yet. When it is all done you will be able to follow along during the entire design process. Some of the new material being added is a direct result of questions asked on the DIY audio forums.

 I have reorganized the site so that I can add new pages without having to re-do all of the links and table of contents on all of the other pages. This meant giving more control to Microsoft (Front Page 2003). The previous organization became impossible to manage. It will no longer be possible to have a link to everything from this home page. The menus (links) on the left bring you to a secondary menu page that has links to the individual pages. The news that formerly occupied this space has been moved to the news page.

06-01-06  Number three was a success! I have added several new pages, with more to come soon. Some of the new pages may have little or no content. That is because I mapped out the design of the web site before I finished the individual pages, and I needed to make sure that all of the hyperlinks work. Content is being added as I have time. I sit in front of a computer for 8 to 10 hours a day at work, when I get home, I would rather play with tubes. All of the old pages are still here (some have been updated) and they are still in the same location, so all old bookmarks and links should still work. Email me if I broke anything. I don't claim to be an expert web designer.

   The PowerDrive circuit has become quite popular, and I constantly get requests for unique designs. There is no way that I have the time to design, prototype, and test each one of these. I am finishing up a new page that should help you design your own. (Actually I am doing it over, it got zapped when my hard drive died)

   Family matters and other commitments have required me to be out of town for many of the weekends so far this year. I now have a work schedule that allows little time for Tubelab. This will continue for the near future. I have tried to set aside one or two evenings per week to answer e-mail. I am currently running about one to two weeks behind responding to e-mail.

5-29-06   Attempt number 3 to upload the new site!

5-28-06   I finally have a free weekend. We are ready for the demo at work, and I have just finished building the new Simple SE PC board. It rocks! I have been blasting this thing with everything from Roberta Flack to Metallica. It is hard to believe that I am listening to $18 output transformers. If I don't find anything wrong with this in a few days, I'm sending the board out for duplication.

5-12-06   I have tested the first prototype of the new Simple SE amp design. It works quite well but there was not enough gain for every application. I have fixed the gain problem by using a CCS load on the driver stage. Now I can reach clipping in triode mode on a quiet CD at less than full volume. This change requires a new PC board design.  Our demo at work has been moved up to May 30. The web site still will not upload.

4-19-06   I am back at home, and the new web site will not upload. I have found out that I must have a prototype design ready to demo on June 15 at work. I finished the PC board layout before going on vacation. Now I have less than 2 months to get them populated (1200 parts on a 3 inch by 7 inch board) and debug the design. Looks like there will be no time for Tubelab.

4-14-06   I have gone as far as I can with the web site, since I don't have all of my files with me to finish the technical pages. I started the PC board layout for a new amplifier design. It is a simple SE design that is geared for the novice builder, but has the features and sound quality of a high end amp. I was originally planning to use the 6AV5 sweep tube but I have been informed that it is not available outside the US. The new design uses any of the popular audio pentodes (6L6, EL-34, KT-88) in triode or UL mode.

4-10-06   I took the laptop with me on vacation. I am designing a new version of the Tubelab web site. I attempted to reorganize the web site so that I could manage it better. The original site was made up of several individual pages that were linked together by a menu system that I made by hand and pasted on to each page. This allowed total control, but became unmanageable as the site grew. It was also the source of the broken links. The new site is built using Microsoft Front Page 2003. It will either work better, or not at all, only time will tell.

 3-31-06 I am currently on the road beginning a 2500 mile road trip. I will meet my grandson, and see my daughter for the first time in almost 3 years. I must be back at work in 10 days, so I will have little time for tube shopping. I brought the laptop to work on this update. It will go live when I get back. This is being written in a hotel room in Rock Hill, South Carolina. Next stop, Moundsville, West Virginia.

 3-24-06 This web site is in the process of a complete makeover. I have about 6 months worth of new information (and some old stuff that I found) that I haven't had time to post. It will take a while to get it all posted. The Tubelab SE assembly manual is being uploaded first. The Tubelab 3 prototyping system is finished, a few pictures are here, more will be added as soon as I can get them processed. Complete assembly details will follow. Several new amplifier designs are done, and will be added also. The PowerDrive circuit has become quite popular, and I constantly get requests for unique designs. There is no way that I have the time to design, prototype, and test each one of these. I am finishing up a new page that should help you design your own.

    I plan to put a lot of new and old content on this site over the next few months. This requires some better site organization. It will no longer be possible to have a link to everything from this home page. The menus (links) on the left bring you to secondary menu pages that have links to the individual pages. The news that formerly occupied this space has been moved to the news page.

   All of the old pages are still here (some are updated) and they are still in the same location, so all old bookmarks and links should still work. Email me if I broke anything. I don't claim to be an expert web designer.

   I have concentrated on functionality and content, I will make it look nice as time permits. Some of the new pages may have little or no content. That is because I mapped out the design of the web site before I finished the individual pages, and I needed to make sure that all of the hyperlinks work. Content is being added as I have time. I sit in front of a computer for 8 to 10 hours a day at work, when I get home, I would rather play with tubes.

   Family matters and other commitments have required me to be out of town for many of the weekends so far this year. This will continue for the near future. I have tried to set aside one or two evenings per week to answer e-mail. I am currently running about one week behind responding to e-mail.

   01-07-06 I have got a new internet hosting account with far more bandwidth than I had before, for the same price. I can now put all of my ideas on the internet without worrying about the cost. Many have requested the Tubelab SE PC board assembly manual, so it will happen first. The PC boards will also be available at this time.

   12-27-05 I have now recovered much of the data that was lost when the hard drive in my main computer died. I now believe that the drive just died, unrelated to my poor programming ability. The drive has become extremely temperature sensitive. I have discovered that If I put the drive in the freezer for a while to get it real cold, then put it into the computer, it will work for about 15 minutes. I have been running back and forth between the freezer and the computer for a few days. I have recovered most of the data that was not backed up. Some of the pictures for the assembly manual were corrupt. I have recovered my e-mail, and will be answering the unanswered mail as soon as I reload all the software on the new drive. I have got a new laptop (which I am using at this moment) that contains an image of the web site so that the web site exists in at least two places. All of my software writing experiments are being moved back to the old computer just in case they had anything to do with the crash.

   12-22-05 Last week I learned why it is important not to use your primary Windows computer (the one that does this web page and stores all e-mail) for dumb Linux and "C" experiments. A program ran away and wrote garbage over much of the useful data on the drive. I am in the process of reconstructing the data for the new web site from back ups that were 1 month old. Email that was sent to the Tubelab address was trashed, I have recovered less than half of that e-mail. E-mail sent to the Bellsouth address was restored intact.

After this crisis is over, all Linux experiments will happen on a dedicated computer. I got a new Windows laptop that will mirror the Tubelab content of the main machine. This computer could do webpage support. It has been used for development of the big web page upgrade that is coming. Early in January, some of the changes will go live. As these are debugged and become fully functional, more will be added. The entire SE amp board manual will be on the site. Boards will be available at that time. New content is coming.

  11-18-05 We are being told that tropical storm Gamma is expected to visit south Florida late Monday night. I had set back up 1 bench and was working on the second. Now it looks like I must pack it all up and hide it in the closet. Since the window behind the bench leaked about 4 gallons of water during the last storm.

  11-14-05 The wife of a fellow engineer was killed yesterday while riding her bicycle in an appropriate bike path. The path had debris scattered across it, as do most of our roads. The debris likely caused her fatal crash. Another friend of mine was killed while working on a ladder to remove debris from his yard. The ladder fell over backward, his neck was broken.

  11-01-05 I have come to realize that the news that we see daily on our TV is not being shown outside the local area. Every day we see pictures of devastation, long lines, 1000's of people who have been left homeless because their homes have been declared unsafe. It has now been 10 days since the storm hit and there are still between 1/2 and 1 million people (including me) without power, depending on which TV channel that you watch. There are emergency crews from all over the country fixing power. I saw a graphic on the TV news that claimed that they have counted over 11000 broken power poles in Broward county alone. On a normal work day it takes me 15 minutes to drive to work. Now it takes 1 hour. Most grocery stores have no perishables in stock.

Why is this information being not being shown in the national market. Maybe people are sick of seeing this stuff. Or maybe there are forces that don't want the 'potential' tourist to see this, and cancel a trip to Florida. South Florida makes a great deal of money on tourism and real estate sales.

  10-24-05 Hurricane Wilma, the 7th hurricane in 14 months to visit us, has devastated this area. 98%of Broward county has no electricity, and it will be 4 weeks before it will be fixed. Without power, there is no gas, since it takes power to pump gas. I am creating a page of pictures of storm related damage. All of these pictures were taken within bicycle distance of my house (most are within 200 feet) since I am saving what gas I have to run the generator, and many streets are not passable by car. I can post these pictures since I have one of the few working phone lines in the area. Tubelab, and the SE amp boards are obviously on hold for a while. My work place is closed due to damage for at least a week. It will take about a week to clean up the mess. I have lived in Florida for 53 years, this is the worst hurricane that I have seen. Andrew caused worse damage, but over a much smaller area. Wilma has caused severe damage for at least 5 counties. There is a path of destruction that looks like these pictures that is 100 miles wide, and goes completely across the state.

   09-11-05 Just when I had the SE amp board ready for launch, Digi-Key discontinued the line of resistors that I was using. I have replaced the smaller ones with metal film resistors and the larger ones with a different line of resistors. This required re - shooting most of the pictures in the resistors section of the manual. This is almost done. I am in the process of setting up my internet account for payment via PayPal. This can be done by credit card without a PayPal account. When these things are complete, boards will be available. 

    I have received lots of email lately. much of it related to the PC board. I have answered each one individually, but in the process I have discovered several common questions. These comments are intended to answer some of these questions:

   1) The board contains TWO complete amplifier channels, and ONE common power supply. One board is needed along with three transformers and a suitable enclosure to build a complete stereo amplifier.

   2) With this board you can build an amplifier that is optimized for 45's OR 2A3's OR 300B's. Since these tubes have different characteristics, it is not possible to build ONE amplifier that is COMPLETELY OPTIMIZED for all three tube types. The primary differences between the requirements of these tubes is load impedance and supply voltage. This means that the transformer set is chosen for each tube. It is possible to build ONE amplifier that will work well with all three tube types. To do this a compromise must be made. I choose a transformer set that supplies the output tubes with about 310 to 320 volts. This is above the recommended maximum for 45's and 2A3's. I have built 5 amps with this configuration and ran about 20 different tubes through all of them, without issue. I have not tried any globe 45's. 320 volts is a bit low for a 300B and you will give up a couple of watts on 300B's compared to an amp optimized for 300B's. If you are uncomfortable with these compromises, build your amp for your favorite tube type. There is a chart in the manual that outlines all of the choices.

  3) Unfortunately 50's will not work in this amplifier without modification. They require 7.5 volts for the filament, which is above the maximum for the filament regulator IC. Unlike tubes silicon really does not like being fed too much voltage. It would be possible to use an external power supply if you really wanted to use 50's, but these tubes are out of my price range, so I have not tried them.

   4) I know that the price of 5842's has gone up several fold since I started using them. I used to get them for $3 to $4 USD each. Several people have e-mailed asking if there is a suitable substitute. Unfortunately in this board there is no substitute other than the WE417 which is usually even more expensive. I have been searching for a different tube that is just as linear, with good gain, for use in my next design, and I have not found it yet.

  5) Several people have asked me to put the construction manual on the web so they can determine their ability to build this amp. I can not do this since it is over 50 megs in size, and it would use up my bandwidth allotment in a few days. Web hosting plans are like US cell phone plans, you get charged by the megabyte (minute) when you exceed your plans allotment. The difference is that I must guess how many megabytes YOU are going to look at for a year in advance, and plan accordingly. This also limits how much NEW stuff that I can add each month, since the new stuff gets the most page views. I will put SELECTED parts of the manual on the site in the next few weeks, but I must process EACH picture first to reduce its size since I have been near my bandwidth limit for the last two months.

  6) This board can be used as a driver board for a large SE amplifier using 845's, 211's, 833A's or other large tubes. There are two ways to do this. The board can be used without modification by substituting interstage transformers for the output transformers. The interstage transformers then drive the large tubes. A separate power supply is needed for the large tubes. The other way is to use PowerDrive. This requires a PowerDrive board to drive the large tubes. I have been convinced of the virtues of PowerDrive since I discovered it, but others have started e-mailing me, telling me how  it did wonders for their amp. The Power Drive board is not ready yet, but you could build it on perf board, or point to point wiring.

   07-19-05 I had to finish the testing of the prototype 833A output transformer in a hurry. I spent two hours trying to blow the 833A prototype amp up by playing guitar through it at extreme volume levels, complete with feedback and hard clipping. No dice, the amp just kept putting up with my S***, although I did blow the bench circuit breaker twice. I started a new 833A page to present these results. There are pictures and some data from an 833A amp that was temporarily assembled to test a prototype output transformer. The amp took up all of one work bench, and part of another. I put it together in a big hurry (3 hours) and it shows. I got over 200 Watts RMS from this thing, and it took some ridiculous abuse without complaint. All good things must come to an end, and this is no exception. I have already disassembled the amp.

   The revised SE amp instructions are finished and an amp is being built currently. I will be out of town for most of August. The SEamp boards will be offered for sale when I return. This will be in early September. I will be working a zillion hours a week before I leave so this might be the last update for a while.

   I was asked, " Why did you need to rewrite the manual. Was it too hard to follow?"  No the manual was (and still is) easy to follow. The original test and adjustment procedure required making voltage measurements on a live board, and simultaneously adjusting the bias. This is no problem for an experienced builder, the original target user. It became apparent that many inexperienced people wanted this amp. I worked with two of the early consumers to devise a test and adjustment procedure that first timers are comfortable with. This is the multiple meter method outlined on the safe meter use page. This procedure separates the user from the electricity, making the procedure safe for newbies and experienced users alike. Now that digital meters are as cheap as screwdrivers, there is no reason not to have a few.

   07-10-05 I have not had computer access for the last two weeks. Bellsouth (our ISP) was down most of this weekend. Even though I live in a major metropolitan area, all I can get is SLOW dial up, and that doesn't always work. I just got to my email. I have tried to answer everyone as best as I could. The answers to the common questions about the board status is below.

   I sold a few boards to some inexperienced people at work to get their feedback on the assembly manual. I gathered their inputs, and made revisions. The revised manual is almost finished. The safety and safe meter use pages were done at their request, yet these pages get few hits. I will have some one build an amplifier using the new instructions before putting the boards back up for sale.
Unfortunately, my father became ill before I was done and I spent each weekend at his house (80 miles away), or at the hospital. He passed away last weekend, hurricane Dennis visited this weekend, and the funeral is now scheduled for next weekend. My mother needs care, and the legal arrangements need to be taken care of.  Since the weekends are when I usually work on this, not much has happened. I can't say exactly when I will get it all done.
I plan to upload most of the basic assembly and checkout instructions to the web site, so that a potential builder can see what is involved before purchasing a board. I can't say yet when the assembly video will be done since I am new to digital video editing. I will post the progress on the web site.

   I got a question about the picture of the amplifier shown above. Won't the transformers interact since they are so close together? Yes they did! Since that picture was taken I have rotated the power transformer 90 degrees to correct a hum that could be seen on the FFT analyzer when the amp was first switched on. Oddly enough the hum disappeared as the rectifier tube warmed up. Sooner or later I will take new pictures. The hum was only barely audible with my ear to the left speaker, but might have been a problem with more efficient speakers.

   I have plenty of new information to add to the site, just no time to do it. I have an 833A SE amplifier running on my bench. It puts out over 200 Watts RMS at 4% distortion. It uses the same SE amp PC board. I will put the details up when I get caught up with all of the ugly stuff.

   06-26-05  My first grandchild (a boy) was born on 6-18. Unfortunately at the same time my father, who has been in the hospital (80 miles away) for almost a month, was moved into intensive care. Needless to say I have not had the time to finish the assembly instructions. I will get back to this as things return to normal. The safety and meter use pages continue to get few hits, 4 each this week. by contrast the 845SE page got 55 and the 73 Challenger page got 60. Come on people, you asked me to write them, at least look.

   06-14-05  The amp sales are on hold again. I sold about 6 boards to people that I work with. Now that three of these people have started building their boards, the unexpected questions have arisen. I am currently re writing the test procedure, again. I am now writing it for a beginner, even though I had always stated that this was not a beginners amp. I have expanded the section on safety. I now require that you use 3 digital meters to test this amp. After this procedure has been tried by a few people, I will put the boards up for sale. I am sorry for the delay, but I am concerned that an inexperienced person will build this amp and get shocked. I have spent 3 weeks (that could have been used on cool tube stuff) writing the page on safety, and in the two weeks that it has been on the site it has received TWO VISITORS. I have had dozens of e-mails from people expressing their "fear of frying", yet no one visits the safety page. I am adding a new page on safe meter use, it is taken primarily from the new Tubelab SE test procedure, but it can be applied to any amp. If you are going to build a tube amp, read it and then order a few cheap meters.

     06-10-05  About one third of the e-mail that I have recently received is from people desiring to build their first vacuum tube amplifier. It has become apparent that there is tons of vacuum tube related information on the Web. Unfortunately there is little information related to electrical safety. Most DIY web sites just have a warning notice. Some of the questions I have received indicate a serious lack of electrical safety knowledge. I have received questions from people that are already building (or about to start) their first amplifier, who don't know how to use a voltmeter. Even though I had stated that this site was intended for experienced builders, it has become obvious that inexperienced people will (and have) purchased our board. Many of the questions and fears involve powering up the board, checkout, and setting the bias. I have decided to rewrite the sections of the manual that detail these operations, before any more boards are sold. The procedure is being changed to use multiple meters that are connected to the board before powering it up. This makes the "scary stuff" much safer for inexperienced users. Digital meters have become ridiculously cheap, so there is no reason not to own a few. Read the safe meter usage page for details on which meters to use and how to connect them up.

   Since there is little safety information available on the web or in print, I have decided to write my own. There will be three initial pages, electrical safety, safe meter usage, and amplifier grounding. These will be added to the web site as they are finished. Most of the information is based on my 40+ years of electronics experience, and some common sense. Much of the material should be obvious to the experienced tech, but everyone should read it at least once. The material is written in a simple, easy to read format. If you do not understand EVERYTHING presented on those pages, you should not be working on high voltage electronics.

   I intend to continue the series on safety because I believe that the information is not well covered on the internet. Electronics can be a safe and rewarding hobby if you have the knowledge and the skills to practice safe electricity. I DO NOT intend to cover introductory electronics, and basic vacuum tube theory. I have only limited time to spend on this site, and I choose to spend it on new and unique amplifier designs. I WILL continue to search for this information and post links to it on the information sources page.

  There has been an increase in e-mail lately, with a few common questions which I will address here:

    1) What is required to build your Tubelab SE amplifier?

    To build the SE amp board, you will need to be able to solder. The instructions are written for someone who has never assembled a PC board before, but soldering skills (and equipment) are assumed. You will also need a digital meter capable of measuring up to 400 Volts. You will need to make several voltage measurements during initial board checkout. This is easily accomplished with 3 cheap digital meters. See the safe meter use page for a preview of the setup. You will also need to manually set the bias for the output tubes  initially and every time the output tubes are changed. This requires taking voltage readings on a live amplifier and adjusting a trimmer potentiometer to get the right reading. These steps are fully explained in the manual, but if you have never done this, you MUST enlist the help of an experienced person. All vacuum tube equipment operates on potentially lethal voltages.

    A computer is needed to view the instruction manual CD. I find that it is helpful to have the computer located near the assembly workspace. The instruction manual is heavily supplemented with digital photographs of many steps in the assembly and test procedures. The instructions are in web page format so they can be viewed using a web browser like Internet Explorer. The images that are included in the pages have been adjusted such they fit in the web page and can be viewed on any monitor at 800 X 600 or higher. The original high resolution images taken with an 8 megapixel camera are included on the CD so that intricate details can be viewed if needed. I am in the process of making a movie file of the initial checkout and setup of a new board. This will be a .mpg file which is viewable in Windows Media Player. I may be able to provide a Mac viewable movie but this is not known at this time since I do not own a Mac, and they have been banished by the IT department at work. Several other files relevant to the construction and operation of this amplifier are provides on the CD.  A text version of the instructions are included, so it is possible to print these and build the board, but this is not recommended.

    2) Why is bias adjustment required? My friend doesn't have to set the bias on his SE amp.

    Your friend's amplifier probably uses "cathode bias". This does indeed require no adjustments. It also restricts the amp to one type of output tube. Our amplifier has a bias adjustment so that you can run different types of output tubes, usually with only a readjustment of the bias control. Some experienced SE amp users often set the bias differently for different musical situations. This amplifier design was conceived as an extremely flexible SE amplifier of very high quality. It was never intended as a beginners amplifier. There is a beginners SE amplifier in the works though.

    3) There has been more than one person who has said that the web site is "confusing" or "hard to follow". Some have asked for more information for " a tube amp newbie". Some have asked for me to do a 300B - 6SN7 - 5AR4 amp. Others have said "Why all of the car pictures?" or "Where are the rest of the car pictures?"

  Ok, I can see how this web site has become disorganized over the past two years. I plan to do a reorganization of the whole site after the SE amp board is all finished. This site was never intended as a "newbie" site. That has been stated on this page since the first day it went live. Look below under "A word  about this site". I also state that I didn't want to do the same designs that are already all over the web. A 300B - 6SN7 - 5AR4 amp has definitely been covered well on the web. I have built amps like this and I was not all that impressed. 6SN7's all tend to be microphonic. That is why my amps use the 5842 input tube. Since I get several questions from newbies, I will try to find some good "newbie" sites and books and list them on this site. The car pictures are simply an outlet for two of my other hobbies, muscle cars and photography. I have thousands of photos from years of car shows. Each one must be processed to be used on the web. More pictures will be added as time permits.

   4) A beginners SE amp?  Tell me more.

    Yes, there is a "plug and play" SE amp in the works. I have had several requests for this, so the amp is beginning to take shape on my Tubelab 2 prototype system. The output tube will be a 6AQ5. The input tube has not yet been chosen, but will likely be some type of dual triode. Why a 6AQ5? I never heard of that. The 6AQ5 was chosen because it is a true audio tube, it can be run as a triode for 2 Watts or as a pentode for 4 Watts. Millions of them were produced so they are cheap ($3 to$5), and they were produced by just about every tube manufacturer so there are several popular brands to choose from. It also happens to sound good. Some other low cost amplifier kits use TV vertical output tubes, or tubes that were only made by one vendor. It is too early to set a price for the kit yet, but the target is for a complete SE amplifier kit (circuit board, parts, and transformers, no cabinet) in the $200 range.

    There have been several e-mails lately asking questions about the SE amp board, the Tubelab SE amplifier and the costs involved in building a complete amplifier. I have updated the  SE amp board page with the answers to many of these questions and some new information.