Thanks - I was confused by the drawing on the Mouser site - the way they show the outline is misleading (sort of an exploded view):
Attachments
44-0-44vac ct 700va trafo..any chance here or way too high voltage? Spare donut sitting on the shelf, would love to use it for something good and simple.
That a bit too high a voltage for the output Darlingtons. 44 X 1.4 = 61V rails, or 120V together, while the TIP series Darlingtons only go to 100V, and you need some margin, say 80%. I was going to suggest a bucking transformer, but you'd need to buck the 44V all the way down to 28V. Maybe just sub higher voltage devices all the way around. You'd need 150V capability to get 80% margin for 61V rails.
Another crazy thought would be a choke input filter, but that adds another piece of monster iron, with the danger of the rail voltages going too high if you stray below the critical current for the filter. That may mean setting the amplifier bias so that it runs in Class AAAAB - big heat sinks, too...
Another crazy thought would be a choke input filter, but that adds another piece of monster iron, with the danger of the rail voltages going too high if you stray below the critical current for the filter. That may mean setting the amplifier bias so that it runs in Class AAAAB - big heat sinks, too...
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Okay, let’s forget that! I have another trafo from Pioneer 757 mk II with 26-0-26 and 36-0-36 secondaries, have no clue about it’s VA rating though.
I would suspect that the 26V windings are the power windings for the output stage, and the 36V windings get regulated and run the input and VAS - that's how I'd do it anyway. What's the power rating of the 757?
I looked at the A616 service manual - the power amplifier is powered by + -48V (2x36VAC) - so its fine for AB100.
2x26VAC is a low power winding.
2x26VAC is a low power winding.
And well if you want to build a monster with 2x44VAC - you can use these:
https://www.onsemi.com/pub/Collateral/MJH11017-D.PDF
and maybe ztx swap to 451/551
https://www.onsemi.com/pub/Collateral/MJH11017-D.PDF
and maybe ztx swap to 451/551
Pass BOM by jwjarch
Hi All,
Not sure if I posted this previously but I was PM'ed about it so here is the BOM I created for the NP pass boards for those interested.
Thanks!
Hi All,
Not sure if I posted this previously but I was PM'ed about it so here is the BOM I created for the NP pass boards for those interested.
Thanks!
Evening all, sorry for not reading the whole thread yet, I will do so when I decide to build the amp !😉 Is this a good sounding amp to build ? Does it have a warmer type of sound, eg more 2nd higher harmonics ? My transformer is a bit high, 65 Vdc after rectification, I don't want to turn in down, but I will if necessary. Maybe there are other transistors that can be used that are not toooo expensive🙂.Something just tells me to do it. Almost all my previous builds were lateral mosfets or hexfets, except for a P3A.I mean, it is a NP amp after all ! All help and info will be appreciated.
hello
yes - everything has been discussed here before. with + - 65 V all transistors need to be replaced, of course it is not easy and will be more expensive.
As for the sound: I wouldn't call it too warm - rather it reminds me of F5, but with clearer and more powerful bass and not so sparkling top note.Anyway, I like it.🙂
yes - everything has been discussed here before. with + - 65 V all transistors need to be replaced, of course it is not easy and will be more expensive.
As for the sound: I wouldn't call it too warm - rather it reminds me of F5, but with clearer and more powerful bass and not so sparkling top note.Anyway, I like it.🙂
osscar, thank you for the reply. Yes you are correct, If I decide to build the amp then I will rather look for another transformer. I don't want to turn down the windings of the toroidal transformer that I wanted to use. Info appreciated !🙂
Prasi, do you perhaps know if your layout has been built by someone and is working 100% . I know your layouts are always good, so why not now !!😀 Thanks, it looks superbb, I'm going to order components.
Regards
Jan
Regards
Jan
Hi Jan, i am not aware of anyone actually building this particular layout, but its quite straight forward and so there shouldnt be any problems.
regards
prasi
regards
prasi
Evening all,
What is the Max voltage for the caps, C5,C6,C7,C8 and C12 ? I cannot open the BOM file.If I want to use KSC3503/KSA1381 then I can only get them in 100's from RS, so can I use MJE340/340. I think BD139/140 will be to low voltage. As I see oscar has used TIP150xx transistors.
Help appreciated.🙂
Regards
Jan
What is the Max voltage for the caps, C5,C6,C7,C8 and C12 ? I cannot open the BOM file.If I want to use KSC3503/KSA1381 then I can only get them in 100's from RS, so can I use MJE340/340. I think BD139/140 will be to low voltage. As I see oscar has used TIP150xx transistors.
Help appreciated.🙂
Regards
Jan
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