At the Burning Amp Festival yesterday, we gave away a batch of semi-built
DIY amplifiers which featured Chassis, connectors, transformers, caps,
and stuffed output stages. All had connections supporting stereo operation.
Most of them were Mosfets arranged either as complementary parallel
sets or as all N channel sets.
As we gave them away, it was clear that people were going to need some
help.
I mean you, Variac.
So I'm starting this thread to get a couple of designs together that
can be put together easily. I figure that some F4 type follower systems
will be the easiest, although there's no reason that we can't explore other
stuff.
If you got one of these honeys, or if you want to just follow along, watch
this space.
DIY amplifiers which featured Chassis, connectors, transformers, caps,
and stuffed output stages. All had connections supporting stereo operation.
Most of them were Mosfets arranged either as complementary parallel
sets or as all N channel sets.
As we gave them away, it was clear that people were going to need some
help.
I mean you, Variac.
So I'm starting this thread to get a couple of designs together that
can be put together easily. I figure that some F4 type follower systems
will be the easiest, although there's no reason that we can't explore other
stuff.
If you got one of these honeys, or if you want to just follow along, watch
this space.
Praising your unbelievable generosity for allowing us all at Burning Amp to carry off these bargains, I did have a question about swapping out the included transformer (25+25) in #26 on your list for one of higher voltage (50+50) and higher wattage. My purpose is to use your glamorous chassis for a dual channel, higher wattage line amp using an alternate supplier's amp modules. 
BTW to All: If possible find a way to attend next years Burning Amp Fest ... even if the goody pile is small, the presentations will be many and the crowds bigger and more feisty than ever.
(My BS is Physics as well, also from the UC system, but I haven't really found the time to teach .... too busy making money.)
BTW to All: If possible find a way to attend next years Burning Amp Fest ... even if the goody pile is small, the presentations will be many and the crowds bigger and more feisty than ever.
(My BS is Physics as well, also from the UC system, but I haven't really found the time to teach .... too busy making money.)
Awesome!
I took home one of these and I'll need lots of help for sure. The only amplifier I have ever built is a chipamp kit.
Mine came with complementary bipolar outputs. My first step was going to be to figure out the circuit that's already installed and diagram it, then go looking for a suitable input stage.
I don't need a lot of power, 10 watts would be enough. I definitely want to be biased into Class A and I would like to have balanced inputs.
I took home one of these and I'll need lots of help for sure. The only amplifier I have ever built is a chipamp kit.
Mine came with complementary bipolar outputs. My first step was going to be to figure out the circuit that's already installed and diagram it, then go looking for a suitable input stage.
I don't need a lot of power, 10 watts would be enough. I definitely want to be biased into Class A and I would like to have balanced inputs.
We should not impose on Nelson to too great an extent ... probably could use this link (diyAudio Forums > Top >Amplifiers >Pass Labs >Burning Amps) as our touch stone for tech support, parts swaps, glad handing, etc. etc ...
So, anyone want to swap transformers? I have a UPS account ... I will be sweetening any deal with the MOSFETs and boards from my box ...
So, anyone want to swap transformers? I have a UPS account ... I will be sweetening any deal with the MOSFETs and boards from my box ...
I ended up with #25. 4 complementary pairs per side, 2X40 and
about 330VA if the Avel number is valid. I'd be very happy to head
in the F4 direction, though it looks like the voltage needs to be lower
to be in line with the F4 schematics. Happy to obtain an appropriate
transformer. Your offer to shepherd is a huge bonus on top of the
material generosity.
Skip
about 330VA if the Avel number is valid. I'd be very happy to head
in the F4 direction, though it looks like the voltage needs to be lower
to be in line with the F4 schematics. Happy to obtain an appropriate
transformer. Your offer to shepherd is a huge bonus on top of the
material generosity.
Skip
OK Nelson....
Guys, the main reason Nelson is going on about this is that he gave me the extraordinary gift of two of the big chassis that were each of monoblock configuration! When my wife gets back from her latest business trip won't she be pleased!
My brother Jon won an auction for a chassis too, so I WILL need help.
One can't have to many F4's, though I think that my current F4's are pretty cool
but I now need to make a high output preamp- maybe with 4 channels now!
Mark
Guys, the main reason Nelson is going on about this is that he gave me the extraordinary gift of two of the big chassis that were each of monoblock configuration! When my wife gets back from her latest business trip won't she be pleased!
My brother Jon won an auction for a chassis too, so I WILL need help.
One can't have to many F4's, though I think that my current F4's are pretty cool
but I now need to make a high output preamp- maybe with 4 channels now!
Mark
Skip_Pack: I got one the "shorter" (but not much lighter) units = #26 = Two 100 VDC (working) 15K caps and the 25/0/25 xformer with the 'fets and boards ( http://www.diyaudio.com/forums/showthread.php?postid=1637142#post1637142 ) ... trade? ... variac ?
My "unknown" transformer is of a type I'm not familiar with. It has the usual dual primaries, but the secondary wires consists of 2 reds, 2 blues and a white wire.
voltage across the reds is about 80V, across the blues is 96, and from the white to either red is 40V and the white to either blue is 48V. That's with the primaries in parallel.
Even if I run the primaries in serial it's not a real good fit, but I do have a 330VA 25+25 toroid from an old project that I never finished.
voltage across the reds is about 80V, across the blues is 96, and from the white to either red is 40V and the white to either blue is 48V. That's with the primaries in parallel.
Even if I run the primaries in serial it's not a real good fit, but I do have a 330VA 25+25 toroid from an old project that I never finished.
I'm sad I couldn't make it this year. Then again, I'm sad every year I cant make it (which has been all of them so far since finding this forum lol). Should start saving for the trip now, i guess.
and yes, greedy me wishes for one of those "mostly built" amps too. I can't deny that in the least
-Jared
*edit* I'll pay shipping and a reasonable handling/packing charge if anyone doesnt want theirs
and yes, greedy me wishes for one of those "mostly built" amps too. I can't deny that in the least
-Jared
*edit* I'll pay shipping and a reasonable handling/packing charge if anyone doesnt want theirs
Six_Pack / Preiter -- " We're reasonably closeby. ... We might benefit by stumbling through this cooperatively ..."
If you guys swap out, let me know if there are any leftovers ... I can come down some weekend or trade via UPS at my expense ... My transformer is 25+25 (dual 120/240 primaries, 330 VA?) and I do want to "upgrade" to 50+50 for a rail voltage above +/- 75 or +/- 80 VDC. ... Preferring wattage around 500 to 600 Watts, although for my purposes, this is generous.
I know this may be a stretch, but if no joy, I'll just buy the proper one somewhere. (I don't think this is a waste of bandwidth at all, but if email is preferred, so be it.)
If you guys swap out, let me know if there are any leftovers ... I can come down some weekend or trade via UPS at my expense ... My transformer is 25+25 (dual 120/240 primaries, 330 VA?) and I do want to "upgrade" to 50+50 for a rail voltage above +/- 75 or +/- 80 VDC. ... Preferring wattage around 500 to 600 Watts, although for my purposes, this is generous.
I know this may be a stretch, but if no joy, I'll just buy the proper one somewhere. (I don't think this is a waste of bandwidth at all, but if email is preferred, so be it.)
I'm happy to conduct this on the forum -- I'll let Variac provide guidance
if we're too mired in minutia. Here's a clip from an email I just sent
to Prieter:
I got the various data sheets and the F4 manual with schematic. My
chassis has complementary IRF230's while the F4 uses IRF240's (N
and P channel pairs). While I'm not knowledgable enough to say for
sure, it looks like the 230's are more or less the same with a current
rating slightly below half that of the 240's. It's possible the front end
of the F4 could plug right in.
Skip
if we're too mired in minutia. Here's a clip from an email I just sent
to Prieter:
I got the various data sheets and the F4 manual with schematic. My
chassis has complementary IRF230's while the F4 uses IRF240's (N
and P channel pairs). While I'm not knowledgable enough to say for
sure, it looks like the 230's are more or less the same with a current
rating slightly below half that of the 240's. It's possible the front end
of the F4 could plug right in.
Skip
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