Member
Joined 2002
The bias setting you have suggested is OK. As for the hiss that can be expected.
The small hum, I would increase your supply filtering I currently use 40,000uf per supply rail. But use as much as you can afford.
Cheers
Anthony
The small hum, I would increase your supply filtering I currently use 40,000uf per supply rail. But use as much as you can afford.
Cheers
Anthony
Member
Joined 2002
well for my av800's ill be using 200k per block. Do you recon that the av800's get hot. ? i think i might have to use fans with my av800's
JasonL said:
Heat, buzz, hiss etc without signal and without load are often signs of oscillations. Scope the output and look for it, not just in the audio band but up to 10 or more Mhz.
Jan Didden
PSU
Hi! Trafo on picture were 800VA, later changed to 500VA.
Now running +/- 60V.
Caps are 22 000uF RIFA (100V), 8pcs of them...and 4 x 1000V/35A briges. Also have 4 x 1uF film-caps in parallell w. each bank, and a 10K-10W bleed-resistor.
Arne K
Hi! Trafo on picture were 800VA, later changed to 500VA.
Now running +/- 60V.
Caps are 22 000uF RIFA (100V), 8pcs of them...and 4 x 1000V/35A briges. Also have 4 x 1uF film-caps in parallell w. each bank, and a 10K-10W bleed-resistor.
Arne K
replacement parts
One big problem with building this amp is that the semiconductors are showing there age. The 2SA970 are no longer available from Digi-key or mouser. Can someone recommend a replacement, maybe something from Zetex. It’s always scary using replacement parts, you don’t know how it’s going to change the sound.
This seems like a nice amp and this one is high on my list of candidates. The heat dissipation on the pass labs alpha amps is very high
. I calculate the idol dissipation of this amp to be 3*(.033v/.33ohm)*(70v*2) = 42watts. Does anybody know how many of dose watts are in class-A?
Also some have commented that the highs in this amp are not on pare with the rest of the amp. What exactly is wrong with it ? Is it harsh and ss sounding. Does this amp sound like a tube amp? I am especially interested on comparisons with the pass labs alpha amps.
One big problem with building this amp is that the semiconductors are showing there age. The 2SA970 are no longer available from Digi-key or mouser. Can someone recommend a replacement, maybe something from Zetex. It’s always scary using replacement parts, you don’t know how it’s going to change the sound.
This seems like a nice amp and this one is high on my list of candidates. The heat dissipation on the pass labs alpha amps is very high
. I calculate the idol dissipation of this amp to be 3*(.033v/.33ohm)*(70v*2) = 42watts. Does anybody know how many of dose watts are in class-A? Also some have commented that the highs in this amp are not on pare with the rest of the amp. What exactly is wrong with it ? Is it harsh and ss sounding. Does this amp sound like a tube amp? I am especially interested on comparisons with the pass labs alpha amps.
My N-channel is still my prefferred (primary) amp, for full-range use.
Guess careful matching of ALL components paid off...
And if anyone can make more PCB's, I want a pair (or two...).
Arne K
Guess careful matching of ALL components paid off...
And if anyone can make more PCB's, I want a pair (or two...).
Arne K
Member
Joined 2002
I blew up my n-channel buy mistake. : O ( BUT i too would like a pair also. They are great and strong little amps..
I would also like to buy PCB-s for N channel Amp. Maybe someone has drawn his one pcb and would like to share his work ???
Mouser has a replacement for the 2SA970 the part number is NTE290A. I don’t know how close it comes to the 2SA970, so I’m still going to keep looking for the 2SA970.
As for the PCB, I’ll also need one. I will draft up my own board. Because I only have limited time to concentrate on this task, I estimate it will take me one week to drop in all the components and three or four weeks to optimize the board in the way I want. Because I don’t truly know when I’ll be done and my board may and up using unusual components, I don’t recommend that anyone should whate up. I don’t know if I’ll make the board myself or send away for it. If I send away for it they will come out a lot nicer looking then my own work, plus I can use two layers.
However if anyone wants I will post updates of my work. I do all my work in ExpressPCB. It’s a free program and it’s the only one I truly know how to use well. Unfortunately they try to stop you from making the boards your self by not making the background white.
As for the PCB, I’ll also need one. I will draft up my own board. Because I only have limited time to concentrate on this task, I estimate it will take me one week to drop in all the components and three or four weeks to optimize the board in the way I want. Because I don’t truly know when I’ll be done and my board may and up using unusual components, I don’t recommend that anyone should whate up. I don’t know if I’ll make the board myself or send away for it. If I send away for it they will come out a lot nicer looking then my own work, plus I can use two layers.
However if anyone wants I will post updates of my work. I do all my work in ExpressPCB. It’s a free program and it’s the only one I truly know how to use well. Unfortunately they try to stop you from making the boards your self by not making the background white.
One of you can make a computer aided PCB with the help of this track layout as a guide: http://www.diyaudio.com/forums/showthread.php?s=&threadid=2469&highlight=
And here is a rather poor quality picture of the assembled board.
And here is a rather poor quality picture of the assembled board.
Attachments
I was just taking a look at Anthony Holton’s site http://www.aussieamplifiers.com to see if anything has changed. It looks like he has a new n-channel amp coming out. It uses 8 output devises and an extra buffer stage. No schematics are available yet.🙁
Attachments
hi
sam , if you have made the pcb with track maker (circuit maker sf) could you please mail it to me _ tubu_cruise (at) yahoo.co.in EDIT: removed the @ char, P-A, Spam protection
by the way i am making , 6 - 2226 , 6 - 2242 , 12 nos - 18 peavey low riders , 12 peavey 500 mid bass pls mail me if you would like more info
thanks
suranjan
sam , if you have made the pcb with track maker (circuit maker sf) could you please mail it to me _ tubu_cruise (at) yahoo.co.in EDIT: removed the @ char, P-A, Spam protection
by the way i am making , 6 - 2226 , 6 - 2242 , 12 nos - 18 peavey low riders , 12 peavey 500 mid bass pls mail me if you would like more info
thanks
suranjan
oh by the way , for pro audio u should be here
http://www.audioasylum.com/scripts/etv.pl?forum=pro
i dont know if you have checked it out already - lots of proper info
suranjan
http://www.audioasylum.com/scripts/etv.pl?forum=pro
i dont know if you have checked it out already - lots of proper info
suranjan
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