Tube Audio Design TAD-60 schematic?
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SoCal Sam
Lunatic Member
Congrats, the TAD-60 is a very nice sounding amp. I played one against a MC275V and the sound was very close.
IIRC, the TAD-60 is point to point so it shouldn't be too hard to figure out. All you need to know is the bias range for your output tube and adjust from the top.
IIRC, the TAD-60 is point to point so it shouldn't be too hard to figure out. All you need to know is the bias range for your output tube and adjust from the top.
writethis
Well-Known Member
Thanks Sam. I'm really jazzed about getting this thing. Don't have an immediate need for the schematic, not planning on jumping in and doing any mods any time soon. My tweaking will be focused on swapping in different tubes once I hear what the amp is doing in my system with the tubes already in it. But in my experience, the best time to harvest info & documentation(whether you need it or not) is while you're pacing around waiting for the big brown truck arrive. iMO this is also the optimal time to read every online review 27 times. 
So I still have several more days of pacing...
ity:
And yes, the TAD-60 is all point to point.
So I still have several more days of pacing...
ity:And yes, the TAD-60 is all point to point.
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mwc951
Member
It's a lovely amp. Check my avatar. So smooth with Heresy I's!
I replaced the pots with Alps Blue Velvets.
The plastic threads on the originals were stripped, causing the entire pot to spin.
I'll look in the packaging for a schematic, but IIRC no documentation what so ever
came with the amp. I'm sure you are aware Paul Grzybek passed away last year
and the BusyBee / TAD website has been taken down. Enjoy the amp!!
I replaced the pots with Alps Blue Velvets.
The plastic threads on the originals were stripped, causing the entire pot to spin.
I'll look in the packaging for a schematic, but IIRC no documentation what so ever
came with the amp. I'm sure you are aware Paul Grzybek passed away last year
and the BusyBee / TAD website has been taken down. Enjoy the amp!!
vinylkid58
Super Member
Yes, one channel and the PS is shown.
I downloaded the T8C-60 schematic from that site and did a schema to actual part comparison with my own TAD-60. The only difference that I found were the capacitor and resistor values in the power supply listed in the schema were a bit lower values than I found actually used in my amp. And it appears that a very small bypass(?) capacitor was added to the resistor going to pin 2 of the 12AU7's. I was not able to physically locate the 9.1K resistor and the 2uF 400V cap I have circled and labeled with Location?
I attached a copy of my notes. All other components matched the schema.
This is a shot of one part of the PS circuit, there are actually 2 separate B+ supplies, I didn't get a good enough picture of the other caps and resistors to complete my analysis.
The other caps and resistors:
The small bypass cap on the resistor to pin 2 of the 12AU7's:
Hope this helps, and I hope someone could verify my findings, I'm not that knowledgeable.
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I think the actual construction of the amp is pretty nice. I just had one helluva time figuring out what some of the caps were. The resistors appear to be Russian surplus and some of the caps are "big name" brands, but the "blue box" caps were a great educational exercise for me. :headscrat
MWC951, did you notice any improvements from changing out the pots? I was thinking of doing this myself after seeing the cheapo pots that were in there. Only downside is that it's going to be twice as expensive-looks like both the volume and feedback pots are in the signal path and would both have to be swapped.
Interesting Fran604g, I took a peek under the hood of my TAD-60 recently and spotted some minor differences between mine and yours. Mine does not have any of the blue square caps or the black cap under the right output tranny. Were there different revisions of this amp? I know that there was a model that came out after mine with LED meter biasing. Here's a glory shot of mine.
Interesting Fran604g, I took a peek under the hood of my TAD-60 recently and spotted some minor differences between mine and yours. Mine does not have any of the blue square caps or the black cap under the right output tranny. Were there different revisions of this amp? I know that there was a model that came out after mine with LED meter biasing. Here's a glory shot of mine.
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That's really interesting, it certainly looks a bit simpler/neater than mine. I was considering unwrapping my PS caps to verify their manufacture, but decided I didn't want to risk damaging anything. I assumed the quantity of caps used in mine were just an attempt to piece together the proper values needed. I don't know how many different versions of the amp there may have been, Paul wasn't very revealing about the actual design/build of the amp the few times I corresponded with him via email/phone.
Do you know the date of manufacture of yours? Mine was Nov. 2006. SN 110606A.
Maybe we can start compiling some data here. I'm really curious about how many he built. :scratch2:
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I also have this amp. I believe Paul came out with a lower power version of the TA 60 it was 45-50 watts instead of 60 watts like mine. The innerds of mine look more like the simpler version.
Michael
Looks like mine was built just prior to yours - Feb 2006. IIRC the LED versions came out in 2007. As for your extra capacitors, I would be a little surprised if they were used merely to arrive at an equivalent capacitance. Did they just run out of parts but happen to have other various value caps lying around? It is also possible that Paul made some tweaks to the design. I am curious to see how close our amps are to the schematic. For now my amp is back in the rack but next time it comes out I'll check it out and see if I can account for any of the discrepancies you found.
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You're welcome, glad I could help.
