Modifying the TAD-60


I was an early adopter of this pretty good amp that was imported by the late Paul Grzybek. Paul was very good communicator an shared a lot with me over the years before he passed.
I was inspired to do some mods by what one A'goner sold earlier this year, which was a massive rebuild. This amp is actually listed again presently.
Mostly PS stuff which I am planning to do, but also some changes to the driver circuit. I will be starting this weekend and reporting my progress and welcome any info or suggestions, of course criticism as long as it is in the DIY spirit.
pelliott123
I have replaced the coupling caps and the stock wire in the signal path with better quality, and the improvements are quite noticeable. I also removed the volume pot from the input circuit and shorten the input wiring quite a bit. I am starting to hear what I call "magic" in the system. Its what I hear when I am in the presence of a truly high end system. I am sure this is partly to do with the coupling caps burning in. This is quite exciting, hearing the changes after living with this amp since new in 2007.
I want to move the input jacks right next to the 12ax7 but this is going to be difficult because of the sub-chassis that the small tubes are mounted on. so this is going to wait until after I finish the PS rebuild
I am building the PS now, so far large Toroid for the B+, two 6au4 half wave rectifiers, hammond 193Q choke. For this first phase of the PS transformation I am going to keep the stock tranny for tube filaments and bias voltages. PS new B+ supply will be choke input. Still collecting parts.
Later I will be working on the bias PS.
I will report if removing the pot and shortening the input connections do anything
I added a separate transformer to power the power tube filaments taking some load off the existing transformer. I felt there was indeed sonic improvements and the amp ran slightly cooler.

I added far more capacitance in the power supply and instead of using a power resistor for filtering I included a nice Hammond choke.
I do have a schematic from BEZ amps which is about 90% accurate. Paul G did make some mods, mostly bypassing resistors with small caps and other small mods I am still looking for others.
I decided to remove the volume control and shorten the input wires considerably. I may even mount the RCA's right next to the 12ax7. I wish I could add photos here. if anybody wants to discuss further send me an email:
pelliott321atyahoodotcom
Thanks for all the good info, I just disregard the negative stuff from the trolls,
I replaced the coupling caps in the driver stage with Clarity and the 68k between the two stages with an AudioNote tantalum. I like what I am hearing. I have big power tranny and big 193Q for choke input. using a pair of 6au4 for rectifiers. Do not have the smoothing caps yet. Still looking
Not sure why you want to argue? Anyway, it was a big project and I loved
it! No doubt one can go at this many different ways and I decided to start
with the TAD 60 on this particular project. Let's just have some fun!
It takes little to no practice of soldering or desoldering things. Watch a few tubes, get descent soldering station and repeat same and you're pro. It takes much more to assemble and build from scratch.
Great learning experience is why! I had to understand what was going on in the amp without any schematic or solder by number instructions. I had to desolder many parts etc...all needed skills. I could also compare stock to modified when done which was great. Just another approach to DIY.
I did the mod on that Tad 60 amp and it was fun. The deep cab actually looks quite nice live as the pics don't do it justice. A separate power supply is also a good idea with additional work needed. This was my biggest and most complete amp project to date as I am learning. I was lucky enough to,have a well regarded builder outline the best ways to improve this amp. I learned a great deal from him and this project.

It was a lot of work as I basically replaced most every part except the trannys. I added much more capacitance and instead of the power resistor used a high quality choke for a robust Pi filter. I like to use the large can computer grade capacitors in power supplies combined with chokes. Do not use bypass caps on the large caps as it closes in the sound and sounds a tad unnatural.

I also used solid core copper wire for better sound. As far as the coupling caps go I used Mundorf SGO and if I did it again I would use JB JFX premium film caps instead. I would use these everywhere I can as they have values up to 47uf! They sound better than the SGO's and cost 1/10.

Ya, they are that good.

Bypass the Alps volume pot as it is not that good. If you must have a volume control in the amp, then use a nice Gold Point stepped Attenuator.
Why modifying TAD when you can build your own from scratch instead of MASSIVE REBUILD with TRUE DIY SPIRIT?
I saw that modded TAD 60 go by the other day. Very interesting work, though I am not a fan of the tall cabinet required to fit all the extra parts. To me, an extra chassis for the power supply stuff like in the old VAC 90's would seem to be a more elegant solution. Do you think you will go this far with yours?