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New Millett Hybrid Maxed Amp - Page 6

post #76 of 6599
Hey guys great work, I really want one of these pcb. They look awesome. Will info be posted in this thread when the pcbs are ready for sale?
post #77 of 6599
Quote:
Originally Posted by cronic View Post
Hey guys great work, I really want one of these pcb. They look awesome. Will info be posted in this thread when the pcbs are ready for sale?
Most likely, the GB will be announced in the Head-Fi Group Buy section. It may just be a reference, though, with the actual Group Buy at Headwize.
post #78 of 6599
2nd Proto finished:
post #79 of 6599
Looks great! I should be starting mine tomorrow. How does it sound?
post #80 of 6599
It looks as though it comes a tad short to fit snuggly in the hammond case (ie. the pcb touching faceplate to faceplate). I haven't followed the MHMax at all but maybe it could be made longer?
post #81 of 6599
Quote:
Originally Posted by mb3k View Post
It looks as though it comes a tad short to fit snuggly in the hammond case (ie. the pcb touching faceplate to faceplate). I haven't followed the MHMax at all but maybe it could be made longer?
Yes, you are correct - it's about 3/16" short. I believe cetoole did this to make room for his Noble pot without pushing it too far back into the heat sinks. When using the Alps and the Neutrik PCB jack, though, that extra space will really help pulling all the test points up from the bottom of the board. We'll have to get cetoole's take on it for the real reason, though.

This one verified the circuit and final layout for the DB's. We're hoping we have a configuration for the MOSFET's, too - NeilR is working on those with Bperboy as another test case (he was first, actually). The structure, thickness, and perhaps the final length may change some to put it jam up against the endplates, but nothing will alter enough to change from this case.

The good news is that I used the DB option - the 2SC3422/2SA1359 pairs, and everything worked - the first time out!! I've never had that happen. Everything biases like a charm:

Walwart: 24VAC, 35VA ($6 surplus Basler Electric)
PS: 27.1VDC
Tube Bias: 13.5 (12AE6A GE)
DB Bias (2SC3422/2SA1359): 109.5mV!!, +or- 0.2mV all four ~50ma ea.


EDIT: Prior to firing it up:
post #82 of 6599
Quote:
Originally Posted by The Monkey View Post
Well, count me in and looking forward to the group buy. In the meantime, I'll build my "regular" MH to get back into the swing of DIY, then move on to the Max.
Make that two of us. My job has been an absolute bear lately. Gah!!!!! I miss working on this stuff.

"But focus, you must."

Bite me, Yoda.

So anway, these protos look gorgeous and I'll keep my eye out for YAGB (yet another group buy!).

Thanks, all!
post #83 of 6599
what are the measurement results for this amp?
post #84 of 6599
Quote:
Originally Posted by cotdt View Post
what are the measurement results for this amp?
Gee, I don't know. You could take a STEPS PS circuit, add it to a fully vetted Pete Millett Hybrid circuit, and then top it off with PPA Diamond Buffer, except it biases at twice that, if desired. Then stick an e12 delay on it for good measure, what do you think?

I'm hoping NeilR will RMAA and scope his, but it will be the MOSFET version. Historically, Amb did extensive testing on the original Millett. I've built four of those - all with DB's - and cetoole's is a major improvement.

'Course it's tubes, so distortion measurements don't portray the real picture. I'm sure that didn't answer your question, but it's the best I can do for the moment.
post #85 of 6599
how about the output impedance and the TIM?
post #86 of 6599
I'm not sending you one to review.
post #87 of 6599
Quote:
Originally Posted by tomb View Post
I'm not sending you one to review.
lol =(
post #88 of 6599
Built mine this afternoon. Great little amp and an easy build!
post #89 of 6599
Did you use the BJTs for the output devices on the buffer?
post #90 of 6599
I used the MJE243G and 253.
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