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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
pelliott123 OP
13 posts
 
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
pelliott123 OP
13 posts
 
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
grannyring's avatar
grannyring
6,506 posts
 
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.
pelliott123 OP
13 posts
 
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
pelliott123 OP
13 posts
 
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
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