The Simple SE PC board:
This page describes the Simple SE amplifier board and answers a few recurring questions.
The Simple SE manual page details the assembly of the PC board.
The Simple SE design pages give a detailed explanation of the history, design, theory, and application of this amplifier.
A fresh board being tested on a test stand specially designed for testing these boards.
The Simple SE board is used to make a simplified SE amplifier that uses indirectly heated tubes like the 6L6GC, EL34, KT88 and 6550. This board is used to construct amplifiers from a basic low cost design to a high end triode mode amplifier. The choice of output tubes are all pentodes, which can be operated in triode mode, Ultralinear, and Pentode mode. This can be switch selectable from the amplifiers front panel. The output tubes operate in cathode bias mode, requiring no adjustments. The PC board was designed to be assembled by people of all skill levels. The parts density is about half of the Tubelab SE. The assembly instructions are written with this in mind. There are photographs of every step from the start to final amplifier construction. Screw connections are provided on the PC board. This makes assembly easier and servicing far easier should the PC board ever need to be removed from the amplifier chassis.
I have assembled several amplifiers with these boards, and they all work great. Construction details for some of them are on this web site, with more to follow. I get email asking questions about these boards, a few common ones are answered here:
When can I have one?
They are available now.
Will you offer kits or assembled amps?
Stocking and tracking the inventory of all of the parts needed for a complete amplifier require considerable time especially with all of the variations that are possible. Right now most of my time is used up supporting the PC boards. As time becomes available I may offer parts and kits for these amplifiers.
What else do I need to make an amplifier?
You will need all of the parts to populate the PC board. You will need the 4 tubes, a power transformer, and two output transformers. You will also need the small parts to complete the amplifier itself, like the power cord receptacle, input and output jacks, a volume control, power switch, and fuse holder. There are some optional parts that can be used to improve the performance of the amp. These are all specified on the parts list page.
How much will a completed amplifier cost?
Most amplifiers are expected to cost between $250 and $700 USD, although you could spend less if you have some parts (transformers and tubes), and it is always possible to spend more in this hobby. Shipping and currency exchange rates make the cost of some items significantly higher in some parts of the world.
Can I use tubes other than the ones specified in the assembly manual?
The assembly manual is written around amplifier designs that I have actually built and tested. It would always be possible to modify a design to use a tube other than those specified. Several emails have asked for assistance with a tube that has a different pinout, or different socket than those on the pc board. The most common questions involve 807's or 1625's. These tubes will work electrically, but require wiring a unique socket up to the PC board. Often the modifications would require more work than just building an amplifier designed for your particular tube. This may be possible for an experienced DIYer. I simply do not have the time to offer assistance for these types of modifications.
Can I build this board with DHT's?
This is actually a common question. See the answer above. It seems that there is a demand for a SimpleDHT board that is not as complex as the Tubelab SE. All of the popular DHT's are NOT 8 pin octals with the exception of the 6B4. I have not attempted to wire a 6B4 into this amp yet, so again, I can not support this modification. If I ever try this, and thoroughly test and document the results, I will post it. Other DHT's would require extensive modifications that would definitely make this an UnSimple SE.
What about the 6V6GT, you mention it on the diyAudio forum?
I have indeed built a Simple SE with 6V6's in triode configuration. It is a very sweet sounding amplifier with almost a DHT like sound to it. It only makes about 1.5 watts in triode, and I have not tried UL mode. A small power transformer is used limiting the B+ to about 320 volts. I slapped the amp together in under 4 hours from start to finish so no pictures were taken during the build. It was one of two "prototypes" I built to prove a concept. They will be rebuilt as part of a wood shop class that Sherri and I are enrolled in. The second build up will be documented for the web site. The 6V6 will be added to the documentation, and tube choice pages as time permits.
I am confused about transformers, what kind do I need?
This board is very flexible, so it can be used in amplifiers that operate at power levels from 1 WPC with 6V6's in triode to 15 WPC with 6550's in UL. Obviously the transformer requirements are different for each of these designs. See the Tubes and Transformers page for more details. It is possible to choose the tubes and operating points to fit a set of transformers that you already have.
Do you have any other applications for this board?
This is the condensed version of several questions. Yes, I have done several things with these boards that are not in the manual. There is no way that I could possibly answer the email that would be generated if I posted them all at once. There are several projects that will be posted eventually that use this PC board.