Dennis - did you tried those 2N1099 from Serbia ?
( YU had formidable electronic industry in Yore, but they never made Ge transistor of that size)
( YU had formidable electronic industry in Yore, but they never made Ge transistor of that size)
I replaced the dead Delco transistor with one of ZM's, and I also changed out the two mosfets. Anyway, it's running now with the bias just a smidgen below 1A.
Cheers,
Dennis
Cheers,
Dennis
Ah, Dennis, it seems you're there! very cool!
(But what’s those white wires from rectifier to the front(-led?)?
I'm closing in too! Biased the beast to 85mV / 20mV, offsets are in the range of 0.001...
The germanium went no further than 40°C this time (16°C ambient).
ZM, should I go up to 110mV bias?
Closing the chassis is imminent 🙂
(But what’s those white wires from rectifier to the front(-led?)?
I'm closing in too! Biased the beast to 85mV / 20mV, offsets are in the range of 0.001...
The germanium went no further than 40°C this time (16°C ambient).
ZM, should I go up to 110mV bias?
Closing the chassis is imminent 🙂
@Dennis Hui - nice ...... any tunes heard?
@myleftear - if you swapped for bigger L bracket, I didn't saw picture
40C isn't much, but think about summer - hardly you'll have 16C ambient
@myleftear - if you swapped for bigger L bracket, I didn't saw picture
40C isn't much, but think about summer - hardly you'll have 16C ambient
don't mess with this Geezer too much ....... I did install Backdoor in all my amps - I can pop da fuse in your, whenever I wish
One to rule them all…
https://static.posters.cz/image/750/poster/lord-of-the-rings-the-one-ring-i143.jpg
I was rather speculating that your supreme powers would enable you to see beside the picture (, oh great mighty zm)…
(Oh, and, I popped like some sweet 57 yrs ago and bugged my dad about audio eversince…)
https://static.posters.cz/image/750/poster/lord-of-the-rings-the-one-ring-i143.jpg
I was rather speculating that your supreme powers would enable you to see beside the picture (, oh great mighty zm)…
(Oh, and, I popped like some sweet 57 yrs ago and bugged my dad about audio eversince…)
don't mess with this Geezer too much ....... I did install Backdoor in all my amps - I can pop da fuse in your, whenever I wish
Now I know why the code for all the new tricks on the pumpkin was such a process. Crazy hacking skills.@Dennis Hui - Great news!
A setback. Fuse blew again and I can see burn mark on some of the 0.22R resistors on the Delco channel.
The amp had played for a couple hours last night and for about 4 hours this morning when it happened.
Up until then it was sounding rather nice with the test speakers, so I feel it's worth the effort to get it working.
Anyway, I will go through the rebuild procedure for this channel, but probably won't be able to before next weekend.
Cheers,
Dennis
The amp had played for a couple hours last night and for about 4 hours this morning when it happened.
Up until then it was sounding rather nice with the test speakers, so I feel it's worth the effort to get it working.
Anyway, I will go through the rebuild procedure for this channel, but probably won't be able to before next weekend.
Cheers,
Dennis
Hehehe....with me, you don't need a backdoor installed for fuses to blow. 🙂
The Delco is definitely dodo with the collector and emitter basically shorted.
Hopefully I'll get that channel working next weekend.
The Delco is definitely dodo with the collector and emitter basically shorted.
Hopefully I'll get that channel working next weekend.
Stephen
Did you ever have a chance to test the 2N277?
Given the experience Dennis has had and that I only have 5 1099s an alternative Ge would be nice - obviously the big Si would also but there is something about Ge
Best
Bob
I actually had a 2N277 biased up and running for about an hour to check initial stability but when I went to run an FFT on it, it wouldn't amplify very much at all with several volts of juice being fed to it so I decided that the transconductance must be dismally low and that this was unusable and proceeded to remove it from the amp. Only after putting in a 2N1099 did I realize that I never reinstalled the FE to OS jumper 😉 but by then I was already tired of swapping parts.
I don't have another set of Old Soul boards to play with and I was never successful in trying to curve trace these so I'm at a bit of a loss on how to verify if parts are good or not. Even if you can get a specimen to bias and play successfully, you can't really say anything about longer term survival until several hours later based on some of the failures reported so far.
The pair of Delco 2N1099 in my Old Soul came from global online auction website in a quad along with the 2 that Dennis has and another batch of 2N1099 with unknown markings were the ones I was partially successful with initially (one failed) so I wouldn't say that it's specifically a problem with a specific brand (sorry Dennis).
I got distracted with other things recently but plan to come back to some form of parts testing when time permits as I have some 1T813 now as well.
The amp sounds very very nice! Easily among the quietest of all the amps I've built and absolutely no harsh edges anywhere but not missing detail or feeling closed in at all. I don't drink alcohol but I guess this is what you would compare to a very expensive and well aged bottle of your favourite indulgence in terms of smoothness and pleasure of consumption.
After hours of playing, I can still put my finger directly on the case of the Ge. It's quite hot but not scorching hot. I think it measured 56C last time I checked it. Unfortunately it looks like it will probably be living in the test mule for a few months but that also means it sits on the top of the pile and gets used by default. Nobody would play a class A amp buried under a stack of other amps no matter how much of a FAB you might be 🙂
I don't have another set of Old Soul boards to play with and I was never successful in trying to curve trace these so I'm at a bit of a loss on how to verify if parts are good or not. Even if you can get a specimen to bias and play successfully, you can't really say anything about longer term survival until several hours later based on some of the failures reported so far.
The pair of Delco 2N1099 in my Old Soul came from global online auction website in a quad along with the 2 that Dennis has and another batch of 2N1099 with unknown markings were the ones I was partially successful with initially (one failed) so I wouldn't say that it's specifically a problem with a specific brand (sorry Dennis).
I got distracted with other things recently but plan to come back to some form of parts testing when time permits as I have some 1T813 now as well.
The amp sounds very very nice! Easily among the quietest of all the amps I've built and absolutely no harsh edges anywhere but not missing detail or feeling closed in at all. I don't drink alcohol but I guess this is what you would compare to a very expensive and well aged bottle of your favourite indulgence in terms of smoothness and pleasure of consumption.
After hours of playing, I can still put my finger directly on the case of the Ge. It's quite hot but not scorching hot. I think it measured 56C last time I checked it. Unfortunately it looks like it will probably be living in the test mule for a few months but that also means it sits on the top of the pile and gets used by default. Nobody would play a class A amp buried under a stack of other amps no matter how much of a FAB you might be 🙂
I was already happy with bigun Si Old Soul, now I'm just happier and greedier 😵👽🤓.
I was just thinking - dual inline rail fuses - isn't it not such a good idea to put separate +/- fuses because if you lose one but not the other, you'll have a not so happy channel no? I know I accidentally had this in a few cases in the past but only SissySIT made out of vibranium came out of it with no problems. In other cases, I lost a few active parts and had such great fun swapping and testing.
Dennis has Area-51 PSU. Fugly! Is that a TO-220 heatsink on top of the Ge on the channel at the bottom of the picture?
Cheers,
Stephen
I was just thinking - dual inline rail fuses - isn't it not such a good idea to put separate +/- fuses because if you lose one but not the other, you'll have a not so happy channel no? I know I accidentally had this in a few cases in the past but only SissySIT made out of vibranium came out of it with no problems. In other cases, I lost a few active parts and had such great fun swapping and testing.
Dennis has Area-51 PSU. Fugly! Is that a TO-220 heatsink on top of the Ge on the channel at the bottom of the picture?
Cheers,
Stephen