joehpj
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Posts posted by joehpj
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Is there any benefit to use DC supply for the front end 6922?
The original design was AC and I was thinking if I can further decrease the AC induced noise by using DC supply.
If I am going to use DC supply, should I reference LT1083 to GND or using the 47R on amp board will be just fine?
Thanks!
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KT77 has different internal configuration. Take JJ's spec sheet for example, 6CA7 pin1 was connected to g3 while KT77 has pin1 NC and g3 connected to cathode internally. It won't be a problem in some versions of the Kevin's layout which G3 and cathode was connected on the PCB. But in a certain version of GG's layout, which G3 was linked to anode. It will be a disaster if KT77 was plugged in. I didn't checked the BH's board layout. So if your BH/GG has former board layout, it should be perfectly fine.
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Edited by joehpj
On the 700s page.
●New semiconductor driver with J-FET in the amplification stage
All semiconductor driver unit that has adopted custom-made low-noise dual FET at the first stage, and for the first time in STAX driver unit history J-FET has been employed at the second stage.After so many years, Stax finally ran out of the long obsoleted Toshiba JFET. The 700t is more like a change that has to be done eventually. But still for some unknown reasons, they still refused to employ CCS in their tube amps. And the second of the 700s stage is quite interesting for me. It's so sad that it hasn't been a lot of innovations since the old Stax gone broke, so minor changes now become news.
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Edited by joehpj
It was a small batch made customized. The factory did everything for me.
ps. I have some spare.
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Done. I miscalculated the height needed for all the stuff on the amp boards, so the build is super tight. As the first one made as a prototype, I think it's good enough. I will increase the width and depth by a little bit next time. Now for some serious listening and comparison with Carbon and GG.
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Made some multi-coated front panel recently. This is a small project @ang728 and I ran together. This is our first attempt to try multi-coated for the front panels. I don't know if this kind of finishing will start to peel off in longterm. We'll see. We are thinking making more interesting colors, too. Maybe "Hulk" green or something like that...
The blue one has tapered feet while the red one has real spiked feet.
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1 hour ago, 2b青年爱发烧 said:
Thanks very much for your reply~
1) I checked out mouser and other sale sites, really there was no more high voltage P type devices, sad...but found a few 2sa1968 on taobao.com, maybe I can use them.
3) what if short the resistor? yeah...maybe it's dangerous.
5) sorry I remembered it wrong, is it better with a follower?
use modern SMD ones like STN9360 instead of 2sa1968 on taobao.
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Edited by joehpj
Not really. I think GG has better vocal while Carbon has better both ends extension and a little bit wider soundstage. BH sits between them.
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Edited by joehpj
It's finally done.
Negative GRHV output resistor changed to 3.3R. 170D was substituted with ROHM in GRHV.
As for sound. In Brief, the BH sits between Carbon and GG.
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Part Sourcing Assistance/Advice Thread
in Do It Yourself
I've discovered that the C2M1000170D is now obsolete and currently out of stock on Mouser as well as several other distributor sites.
Has anyone found a good alternative for output transistor for the Carbon?
Thanks in advance.