For the TO -66 mounted on the side? MJE15030 & 31
Your not going to find a used working PC board for one. If you do I also need to replace one gutted from fire on board. There are far better amps out there than what JB designed. Try Briston SP?
Better output stage and far less problems.
Outputs use "ON" 21194 and compliment.
USE NO ECG OR NTE PARTS AT ALL!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Your not going to find a used working PC board for one. If you do I also need to replace one gutted from fire on board. There are far better amps out there than what JB designed. Try Briston SP?
Better output stage and far less problems.
Outputs use "ON" 21194 and compliment.
USE NO ECG OR NTE PARTS AT ALL!!!!!!!!!!!!!!!!!!!!!!!!!!!!
hello Burnedfinger
yes i am looking for the TO66 on the PCB like you can see on the picture. The GAS116/117 are already changed to MJE150028/29 in TO220
Did you already replace the 2N3584 and 2N6421 with the MJE15030/31 ?. Iam a little be worry because for 2N** the Uce =350V, for MJE Uce=150V and rail is +80V to -80V
Wolfgang
yes i am looking for the TO66 on the PCB like you can see on the picture. The GAS116/117 are already changed to MJE150028/29 in TO220
Did you already replace the 2N3584 and 2N6421 with the MJE15030/31 ?. Iam a little be worry because for 2N** the Uce =350V, for MJE Uce=150V and rail is +80V to -80V
Wolfgang
Attachments
As long as you are not bridging them there will be no problems. The SAE forum will also tell you that no one is capable of rebuilding the SAE or Ampzilla except for JB of course and several other hand picked boys of JB's.
I get most of my spending money from rebuilding the SAE's and Ampzilla's that are sent to me from people off the SAE forum because I will fix them for a decent reasonable price.
Pay particular attention to the large resistors on the board because they can and will change value and this will cause you some heart ache.
Good luck. Take your time and you won't have a problem. Also change the bias pot because age will cause a problem here also.
I get most of my spending money from rebuilding the SAE's and Ampzilla's that are sent to me from people off the SAE forum because I will fix them for a decent reasonable price.
Pay particular attention to the large resistors on the board because they can and will change value and this will cause you some heart ache.
Good luck. Take your time and you won't have a problem. Also change the bias pot because age will cause a problem here also.
"DJK, Dennis has corrected my numbers."
The MJE15030/31 are probably OK at ±80V, even though only rated at 150V.
The MJE15029/29/30/31/32/33 family are obtained on a selection basis. They start out the same, they make them, and then grade them. Ones that aren't good enough to be the 250V group become the 150V group, etc. This implies that the 120V group cannot do 150V, and the 150V group cannot do 250V, but may be a bit better than 150V (enough for ±80V)
The MJE15034/35 seem to be a bit different, probably not the same die group.
I don't have the data books anymore on the 2S numbered parts. If someone can give me the links to the data sheets, I may be able to recommend subs.
The MJE15030/31 are probably OK at ±80V, even though only rated at 150V.
The MJE15029/29/30/31/32/33 family are obtained on a selection basis. They start out the same, they make them, and then grade them. Ones that aren't good enough to be the 250V group become the 150V group, etc. This implies that the 120V group cannot do 150V, and the 150V group cannot do 250V, but may be a bit better than 150V (enough for ±80V)
The MJE15034/35 seem to be a bit different, probably not the same die group.
I don't have the data books anymore on the 2S numbered parts. If someone can give me the links to the data sheets, I may be able to recommend subs.
For datasheets take a look at http://www.datasheetcatalog.com/
You will find 2SA839 ( 2SC1669 is complementary)
In Ampzilla it`s 2SA839 Classification O (hFE 70-140)
You will find 2SA839 ( 2SC1669 is complementary)
In Ampzilla it`s 2SA839 Classification O (hFE 70-140)
Transistors on son of Ampzilla
I am repairing a Power amp GAS Son of Ampzilla and am missing the cross references to standard manufacturers for the transistors
Q 101 ( GAS 116)
Q 102 ( GAS 104A)
Q 103 ( GAS 108)
Q 104 ( GAS 107)
Q 105 ( GAS 117)
Q 106 ( GAS 103A)
Does anybody have got an advice on this for the case I have to replace one of the mentioned transistors.
I would be pretty happy to find a solution there since I really enjoy the great sount of this fantastic power amp.
Thanks in advance
I am repairing a Power amp GAS Son of Ampzilla and am missing the cross references to standard manufacturers for the transistors
Q 101 ( GAS 116)
Q 102 ( GAS 104A)
Q 103 ( GAS 108)
Q 104 ( GAS 107)
Q 105 ( GAS 117)
Q 106 ( GAS 103A)
Does anybody have got an advice on this for the case I have to replace one of the mentioned transistors.
I would be pretty happy to find a solution there since I really enjoy the great sount of this fantastic power amp.
Thanks in advance
WolfgangL said:
blmn said:
Hi Wolfgang,
thanks so much for the file you sent attached.
I finally have now thanks to you all the data I need to fix the Amp.
Thanks again.
Hi blnm,
thanks a very lot to you too for your very nice and friendly proposal.
I will use the transistors stated in the list Wolfgang was kind to send so that you do not need to check if you have got the transistors and in the worst case ( I do not wish it to you) if you have them to have them for your own repair needs.
Thanks again
Pile of busted Ampzillas
Hi. I'm bumping this old thread because I have an active project underway to repair several busted Ampzillas. I'm making slow progress based on a limited understanding of the circuit but I'm willing to put in the hours (and hours and hours...) to get the work done right.
Right now I have 2 working 'zillas, a working Son of that I just rehabbed, 2 more zilla chassis and 3 sets of zilla boards needing repair: board types 'F", 'G' and 'B'. The 'F' boards are pretty well smoked but I think they're rebuildable.
I have the information pack from Dave Riddle and I have read over many threads of discussion about these circuits. Some of it I understand, some is in technical shorthand that goes over my head, and there seems to be a lot of arguing on the Yahoo group, which is unhelpful.
Here's one question to start with: I'm looking for replacements for the 2n6421 and 2n3584. Earlier in this thread it appears to indicate that 15028/30 and 29/31 can be used as substitutes, with the only concern being the voltage rating. I have 30, 31, 32 and 33 on hand, maybe a dozen each.
My question is about how to select the devices by Hfe. According to the datasheet that I have for the 2N3584/2n6421, the Hfe is rated at 8 min and 80 max.
The datasheet for the 15030/31 states the Hfe as 40 min and no max. I have a pile of 1503x devices here, about 10 - 15 of each. I ran them all through the Hfe tester on my DMM (for what that's worth) just to see what ranges they turn up in.
The results:
15030: 100 - 150 (NPN)
15031: 190 - 225 (PNP)
15032: 20 - 50 (NPN)
15033: 75 - 130 (PNP)
That looks like a very large difference in Hfe ranges, and much higher than the 8/80 rating of the 2n devices being replaced. Won't inserting new devices with much higher current gain change the performance of the circuit?
Any guidance would be appreciated.
Background: Elecrtronics school in the '70s. IT Professional, audio hobbyist. Primarily tubes. I can do anything with tube audio & have a lot of experience. Solid state, not so much. Direct coupled SS power amps with 20 active devices in the circuit are difficult for me because I don't have an intuitive sense of the method of operation the way I do, say, a Williamson tube amp. I'm also active on AudioKarma, where I was the Speakers forum Mod back in the Jurassic when it was a few thousand people.
Hi. I'm bumping this old thread because I have an active project underway to repair several busted Ampzillas. I'm making slow progress based on a limited understanding of the circuit but I'm willing to put in the hours (and hours and hours...) to get the work done right.
Right now I have 2 working 'zillas, a working Son of that I just rehabbed, 2 more zilla chassis and 3 sets of zilla boards needing repair: board types 'F", 'G' and 'B'. The 'F' boards are pretty well smoked but I think they're rebuildable.
I have the information pack from Dave Riddle and I have read over many threads of discussion about these circuits. Some of it I understand, some is in technical shorthand that goes over my head, and there seems to be a lot of arguing on the Yahoo group, which is unhelpful.
Here's one question to start with: I'm looking for replacements for the 2n6421 and 2n3584. Earlier in this thread it appears to indicate that 15028/30 and 29/31 can be used as substitutes, with the only concern being the voltage rating. I have 30, 31, 32 and 33 on hand, maybe a dozen each.
My question is about how to select the devices by Hfe. According to the datasheet that I have for the 2N3584/2n6421, the Hfe is rated at 8 min and 80 max.
The datasheet for the 15030/31 states the Hfe as 40 min and no max. I have a pile of 1503x devices here, about 10 - 15 of each. I ran them all through the Hfe tester on my DMM (for what that's worth) just to see what ranges they turn up in.
The results:
15030: 100 - 150 (NPN)
15031: 190 - 225 (PNP)
15032: 20 - 50 (NPN)
15033: 75 - 130 (PNP)
That looks like a very large difference in Hfe ranges, and much higher than the 8/80 rating of the 2n devices being replaced. Won't inserting new devices with much higher current gain change the performance of the circuit?
Any guidance would be appreciated.
Background: Elecrtronics school in the '70s. IT Professional, audio hobbyist. Primarily tubes. I can do anything with tube audio & have a lot of experience. Solid state, not so much. Direct coupled SS power amps with 20 active devices in the circuit are difficult for me because I don't have an intuitive sense of the method of operation the way I do, say, a Williamson tube amp. I'm also active on AudioKarma, where I was the Speakers forum Mod back in the Jurassic when it was a few thousand people.
Those old amplifiers will work fine with a modern driver transistor. They don't really need one, however, because the outputs are in series and each only sees half the total rail voltage. Well, maybe a bit more if those large power resistors drifted over time/temp cycling. You could get away with 100 volt grade devices (TIP41/42C) as is used in the Dyna 400. MJE150xx is a better device, and even a 120V grade version is plenty good enough for the application.
As far as how much beta you can get away with, just about anything reasonable. It only has two stages of current gain and I doubt you could over-do it and make it oscillate unless you tried really hard.
As far as how much beta you can get away with, just about anything reasonable. It only has two stages of current gain and I doubt you could over-do it and make it oscillate unless you tried really hard.
Thanks for the reassurance. I had rebuilt one channel and it passed signal but had too much DC offset for the servo to deal with. I knew there had to be some drifty parts. I pulled all of the 2n5551 and 5401 xstrs, replacing them with matched pairs. For the 2n6421 and 2n3584, I pulled them all and replaced them with 15032/33. The channel fired right up (on the Variac!) and settled down smooth and quiet. IT now makes 220W at clip with both channels running.
The other board from this set had some parts fail catastrophically (flames). I pulled every semiconductor and every cap, and all out of spec R's. I'm rebuilding this board with teh same parts I used on the first one so they'll be the same.
When I'm done and both channels are biased up I'll run this for a day at least at 10W into 8 Ohm resistors. After that I'll recheck everything before connecting it to speakers.
Once I'm done with this I'll have only 4 more boards to rebuild! I have one more set of boards than chassis, but something tells me it wouldn't be a bad idea to have a spare set.
The other board from this set had some parts fail catastrophically (flames). I pulled every semiconductor and every cap, and all out of spec R's. I'm rebuilding this board with teh same parts I used on the first one so they'll be the same.
When I'm done and both channels are biased up I'll run this for a day at least at 10W into 8 Ohm resistors. After that I'll recheck everything before connecting it to speakers.
Once I'm done with this I'll have only 4 more boards to rebuild! I have one more set of boards than chassis, but something tells me it wouldn't be a bad idea to have a spare set.
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