The emitter resisters are .1 ohm, 30 mv across each one. I had them as high as 75mv but I could not touch the amp after about an hour. The amp sounds better than expected. Not as nice as the Aleph in the midrange, but much more punch in the low end.
Fred thanks for the heatsinks.
Fred thanks for the heatsinks.
75mV is 81 watts class-A with 160 watts idle dissipation.
30mV is only 13 watts pure class-A but with 60 watt dissipation.
for 50 watts pure Class-A, 59mV is needed. But as you say, we dont know if your heatsinks can take it. Also these calcs were done assuming you have 3 output pairs, I see 2 in your pics...
I am curious, how did the mids sound with the 75mV setting?
30mV is only 13 watts pure class-A but with 60 watt dissipation.
for 50 watts pure Class-A, 59mV is needed. But as you say, we dont know if your heatsinks can take it. Also these calcs were done assuming you have 3 output pairs, I see 2 in your pics...
I am curious, how did the mids sound with the 75mV setting?
MikeW said:Jan and Troy thanks for the board. K-amps thanks for the transformer. Bias 600ma, rails 35 volts
Your very welcome. Thank YOU for the pictures.
So how is it setup? Source, cables and speakers? You mention midrange but what is the associated equipment? I thought I advised people NOT to use it with the Bozo AM-5 speakers.
I AM JOKING.....
Thank you again for the pictures and reinvigorated enthusiasm..
Good Job!
Mike,
Looks great. Hope to find time to build mine some day soon. Plan on only one pair of outputs per channel.
Hope the mids get better with more use on yours.
George
MikeW said:I am only using 2 sets of outputs (mjl 4381,4302). I have a few different pre-amp that I have tried. Some Magnepan and home made speakers.
Mike,
Looks great. Hope to find time to build mine some day soon. Plan on only one pair of outputs per channel.
Hope the mids get better with more use on yours.
George
MikeW said:I am only using 2 sets of outputs (mjl 4381,4302). I have a few different pre-amp that I have tried. Some Magnepan and home made speakers.
2 pairs of outputs and you are running 5.8 watts pure class-A.... perhaps the mids would get better with a higher bias level?
Re: ... still not as good as the Aleph ...
I was talking about the midrange of the Aleph. I said this is a very nice sounding amp. I like it very much.
Miracles do happen. The imagination designs the amp. I work with what I can find. Thanks for the reply.
Looks like a bunch of Spaghetti .......in a box...........
Jam, always thinking about food.
Upupa Epops said:Have you only basic imagination about internal wiring of an amp ? With this " wire salat " you can't wait miracles - miracle is fact, that this connection is able to work.
I was talking about the midrange of the Aleph. I said this is a very nice sounding amp. I like it very much.
Miracles do happen. The imagination designs the amp. I work with what I can find. Thanks for the reply.
Looks like a bunch of Spaghetti .......in a box...........
Jam, always thinking about food.
"They do get better with more bias. For short times I had the bias up as high as 2 amps, but still not as good as the Aleph."
Actually My feeling is that the Aleph presents a rolled off leading edge presentation of things while the Krell HAS the leading edge as part of the presentation. Transients attack with the Krell seems much faster.... wheather it really is or not is another thing but thats the impression I get from listening to mine. A quick comparison of a 10 khz square wave might reveal this. Both are great amps and each has iots strengths and weaknesses.
I noticed a big difference in sound between 350 mv and 420 mv on mine. Also, letting the thing warm up for 3 to 4 hours makes a BIG difference. You can bake cookies while your waiting for the amp to stabilize.... so the electric is not wasted!
Mike, You need to get some fans on that and get the bias back up!
Mark
Actually My feeling is that the Aleph presents a rolled off leading edge presentation of things while the Krell HAS the leading edge as part of the presentation. Transients attack with the Krell seems much faster.... wheather it really is or not is another thing but thats the impression I get from listening to mine. A quick comparison of a 10 khz square wave might reveal this. Both are great amps and each has iots strengths and weaknesses.
I noticed a big difference in sound between 350 mv and 420 mv on mine. Also, letting the thing warm up for 3 to 4 hours makes a BIG difference. You can bake cookies while your waiting for the amp to stabilize.... so the electric is not wasted!
Mike, You need to get some fans on that and get the bias back up!
Mark
Mark A. Gulbrandsen said:"They do get better with more bias. For short times I had the bias up as high as 2 amps, but still not as good as the Aleph."
Actually My feeling is that the Aleph presents a rolled off leading edge presentation of things while the Krell HAS the leading edge as part of the presentation. Transients attack with the Krell seems much faster.... wheather it really is or not is another thing but thats the impression I get from listening to mine. A quick comparison of a 10 khz square wave might reveal this. Both are great amps and each has iots strengths and weaknesses.
I noticed a big difference in sound between 350 mv and 420 mv on mine. Also, letting the thing warm up for 3 to 4 hours makes a BIG difference. You can bake cookies while your waiting for the amp to stabilize.... so the electric is not wasted!
Mike, You need to get some fans on that and get the bias back up!
Mark
Ya that's what I was trying to say.
No fans
Looks fine to me. Any amp that works is a good amp in my book.
Or to put it another way--short doesn't bother me a bit, they're all the same height laying down.
I haven't got a K-anything here to play with, so I don't know how it looks on a scope. For that matter, it's been years since I've heard Krell commercial product, with the exception of that big 600W critter I ran across out in Santa Fe a couple of years ago (the rest of the system was unmitigated crap, so I don't really count that as a valid listening session).
However, Aleph variants I do have. The 10kHz square on an Aleph looks pretty good. If you feel that it's not up to snuff, play with the value of the cap around the feedback resistor. Or with the feedback resistor itself, for that matter. The circuit's pretty forgiving.
Grey
Or to put it another way--short doesn't bother me a bit, they're all the same height laying down.
I haven't got a K-anything here to play with, so I don't know how it looks on a scope. For that matter, it's been years since I've heard Krell commercial product, with the exception of that big 600W critter I ran across out in Santa Fe a couple of years ago (the rest of the system was unmitigated crap, so I don't really count that as a valid listening session).
However, Aleph variants I do have. The 10kHz square on an Aleph looks pretty good. If you feel that it's not up to snuff, play with the value of the cap around the feedback resistor. Or with the feedback resistor itself, for that matter. The circuit's pretty forgiving.
Grey
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