Al
I have 5 pair that I can match real close, the last and only pair I need would work out to about 85 hfe-42/131hfe-92
That's the closest I can come without buying and finding a higher hfe 42 to match the other's
Is that to much of a spread on this last pair?
David
I have 5 pair that I can match real close, the last and only pair I need would work out to about 85 hfe-42/131hfe-92
That's the closest I can come without buying and finding a higher hfe 42 to match the other's
Is that to much of a spread on this last pair?
David
Thanks Al
I almost forgot, But I have quite a few of the 2sc2240/970 that I might try in the front end. That would solve the matching issue.
Have you had a chance to try these on your boards? The bce/ebc pins are different of course.
I use these on my 150 watt mono's, since these were the preferred trannies of Krell's former production manager (Synder) personal circuit at one time (1991)
David
I almost forgot, But I have quite a few of the 2sc2240/970 that I might try in the front end. That would solve the matching issue.
Have you had a chance to try these on your boards? The bce/ebc pins are different of course.
I use these on my 150 watt mono's, since these were the preferred trannies of Krell's former production manager (Synder) personal circuit at one time (1991)
David
I did try them in a prototype, and any differences were very small, so much so that I am quite willing to write them off as psychoaccoustic. That's why I went for MPSAs in the production item - cheaper and more easily available for most people.
Geez.... almost page 500!
I've built them with both the Japaneese and the US made semis and heard no differences at all between them. I don't think this circuit is really critical there as long as you use low noise devices.
Mark
I've built them with both the Japaneese and the US made semis and heard no differences at all between them. I don't think this circuit is really critical there as long as you use low noise devices.
Mark
On the use of the fans for cooling vs. passive heat sinks...I would suggest the passive. I may be able to set my fans at a lower speed, but for now, I can clearly hear the fans during quiet periods in chamber music, and classical. I think I can reduce the fans further because the temps on my heat sinks are so cool to the touch.
I think Mark plans to reconfigure his Krell into monoblocks at a later date as well.
Other than that, no complaints! Sound is very good.
Now the big question is does my post begin the mighty 500 page, or am I just a lowly servant, to support lgreen's ascension to the page throne?
😉
I think Mark plans to reconfigure his Krell into monoblocks at a later date as well.
Other than that, no complaints! Sound is very good.
Now the big question is does my post begin the mighty 500 page, or am I just a lowly servant, to support lgreen's ascension to the page throne?
😉
Hi,
Lgreen has already gone into hibernation, just as Pink is about to follow. They'll both miss it.
Lgreen has already gone into hibernation, just as Pink is about to follow. They'll both miss it.
Hi Mark,
KSA50 & the Klone use slow BJTs for all stages except the Vbe multiplier.
I would expect the amp to show little if any difference if only a few of the slow BJTs were replaced with faster types.
However, if ALL were replaced with medium speed types, right through to the output stage, the sound may well be different.
The stability compensation would probably need adjusting. This may also change the sound. The 47pF is a safe value, for the sake of DIY reliability, for stability compensation and this may be dominating the sound.
Would it still be a Klone?
KSA50 & the Klone use slow BJTs for all stages except the Vbe multiplier.
I would expect the amp to show little if any difference if only a few of the slow BJTs were replaced with faster types.
However, if ALL were replaced with medium speed types, right through to the output stage, the sound may well be different.
The stability compensation would probably need adjusting. This may also change the sound. The 47pF is a safe value, for the sake of DIY reliability, for stability compensation and this may be dominating the sound.
Would it still be a Klone?
Hi UK buyers,
I am still finding trouble sourcing Polypropylenes for C105/6(22pF 0.4/0.6), C101(680pF 0.4/0.6), C104(100nF 0.3).
Rapid and RS don't supply to these pin pitch.
Digikey do C104 but want £25 extra for post and handling to UK.
I can solve 22pF & 680pF by using polystyrene.
For RF attenuation can a polystyrene be bypassed with a small ceramic(47pF) without detriment to sound quality?
Or does the RF attenuation need to be PP or PSty when the effect is all above 100s kHz? Could ceramic alone do for this duty?
I am still finding trouble sourcing Polypropylenes for C105/6(22pF 0.4/0.6), C101(680pF 0.4/0.6), C104(100nF 0.3).
Rapid and RS don't supply to these pin pitch.
Digikey do C104 but want £25 extra for post and handling to UK.
I can solve 22pF & 680pF by using polystyrene.
For RF attenuation can a polystyrene be bypassed with a small ceramic(47pF) without detriment to sound quality?
Or does the RF attenuation need to be PP or PSty when the effect is all above 100s kHz? Could ceramic alone do for this duty?
Hi Upupa,
I used to buy carbonates because they appeared to offer best performance below PP at an affordable price and in a smallish package.
Polycarbonates are almost unobtainable now.
I believe that carbonate film has stopped production. Certainly one of the really big producers announced some while ago they had stopped manufacture of the film.
I used to buy carbonates because they appeared to offer best performance below PP at an affordable price and in a smallish package.
Polycarbonates are almost unobtainable now.
I believe that carbonate film has stopped production. Certainly one of the really big producers announced some while ago they had stopped manufacture of the film.
Hi,
22pF NPO solves the temp variation. But this is not the audio issue with ceramic. NPO still has a voltage dependent variation.
C105/6 is the feedback cap around the VAS and I would have thought that NPO here would have a bad effect on the sound due to voltage modulation of the capacitance.
22pF NPO solves the temp variation. But this is not the audio issue with ceramic. NPO still has a voltage dependent variation.
C105/6 is the feedback cap around the VAS and I would have thought that NPO here would have a bad effect on the sound due to voltage modulation of the capacitance.
Andew, it is mania... Many others factors in this connection have much bigger inpact to sound... Try to change some different type of caps at this position ( for example mica, which is very stabil ) and I guarantee to you, that you will hear any difference... 😉
Oh, God! 500 pages! It's unbelievable! So many Krell fanatics exist all over the world.
Dear Krell owners, try to remember that this great job was promoted by bra, a member of the diyaudio.
Dear Krell owners, try to remember that this great job was promoted by bra, a member of the diyaudio.
Hi Upupa,
I have used three micas in the Leach clone, but I want to assess the sound before I go the same route with the K Klone.
I'll keep that option, for 22pF, open except the legs need to splayed somewhat (5.7mm to 10mm).
I have used three micas in the Leach clone, but I want to assess the sound before I go the same route with the K Klone.
I'll keep that option, for 22pF, open except the legs need to splayed somewhat (5.7mm to 10mm).
