Thanks Per Anders, I got the boards Yesterday. I hope all goes well. I will try to get back on track with these amps in a week or so. Ive got two big jobs back to back. Then free agian. I have'nt yet bought the transistors. I was wondering what some opinions are, do mje 15030/15031 for drivers and 2sa1943/2sc5200 for the output transistors.
It's coming together!
It's coming together and I could not have done it without you guys. It's been fun and scary for me. I will get the most electrifying (no pun intended--well really yes), scary invent when I turn on this thing. I have a VARIAC and will start out slowly. Still waiting for the MJE15032/3 heatsinks from Jim's Audio--Chinese shipping takes "Me do you long time," (Good Morning Vietnam or was it Hamburger Hill?). Will these 15032/33 have to be dielectric and heat sink greased too? What about the 2SK201/2SJ313s? I found a heat sink compound that is military grade, dielectric, non-silicon, non-creeping synthetic ester based compound , temp range -22 to 390 F degrees, thermal conductivity 1.8 x 10-3 and does not harden.
It's coming together and I could not have done it without you guys. It's been fun and scary for me. I will get the most electrifying (no pun intended--well really yes), scary invent when I turn on this thing. I have a VARIAC and will start out slowly. Still waiting for the MJE15032/3 heatsinks from Jim's Audio--Chinese shipping takes "Me do you long time," (Good Morning Vietnam or was it Hamburger Hill?). Will these 15032/33 have to be dielectric and heat sink greased too? What about the 2SK201/2SJ313s? I found a heat sink compound that is military grade, dielectric, non-silicon, non-creeping synthetic ester based compound , temp range -22 to 390 F degrees, thermal conductivity 1.8 x 10-3 and does not harden.
This compound is made by GC Electronics. "Type44 Heat Sink Compound-- Extra High-Efficiency Heat Transfer." I put very little on both sides of the TO-220 MICA insulators with soft brush. Just wanted to throw this out here in case anyone had a negative experience with this type of heat compound. Also, when I want to add a picture to my message of where I am with the main boards, it ask for "PLEASE ENTER THE URL OF YOUR IMAGE." I don't have a website but could put one together ASAP if that what it takes or is there another way?
Hi Stuart. Long time no see. I always wanted to ask. The can transistors seems to be hotter at idle and cooler when signal is applied. Is that correct and why. 40V @ 1kVA toroids, 40,000uF, with 8ohms speakers. Just beautiful sounds at just a few notches on the volume knob.
Hi,
Sorry if this reply is horribly delayed, the notification of the message being in my box was lost somehow.
I think the theory suggests that when the amp is putting power into the speaker, there is less in the transistors, assuming the output stage is not leaving Class A. Our observations seem to confirm this, though I never took the time to actually measure temperatures accurately. Just as the amp moves from ClassA into ClassB, the power dissipated in the output stage should be at it's minimum.
HTH
Stuart
Sorry if this reply is horribly delayed, the notification of the message being in my box was lost somehow.
I think the theory suggests that when the amp is putting power into the speaker, there is less in the transistors, assuming the output stage is not leaving Class A. Our observations seem to confirm this, though I never took the time to actually measure temperatures accurately. Just as the amp moves from ClassA into ClassB, the power dissipated in the output stage should be at it's minimum.
HTH
Stuart
Scusa per la goffaggine, sto usando google translate. Credo che i PCB che hai menzionato fossero per una versione successiva degli amplificatori Krell. Non ricordo nessuno che abbia segnalato problemi con loro, ma la maggior parte delle persone qui ha usato i PCB progettati dalle altre persone nel thread.