OK.
So I've had another look. It's a 630d, fairly recent. No markings on the board though, just "A Brian Powell design".
On the back of the board is written (by hand) "0200".
Anything would be helpful. The amp is oscillating at RF. Any thoughts/experience?
Fantastic sounding amps. I really kicked myself when I shorted it. Crimson catalogue says something like "Output short protection circuit...virtually bombproof". Hmmm.
Cheers!
So I've had another look. It's a 630d, fairly recent. No markings on the board though, just "A Brian Powell design".
On the back of the board is written (by hand) "0200".
Anything would be helpful. The amp is oscillating at RF. Any thoughts/experience?
Fantastic sounding amps. I really kicked myself when I shorted it. Crimson catalogue says something like "Output short protection circuit...virtually bombproof". Hmmm.
Cheers!
A picture of the man and some history here:
http://www.aufi.co.il/amp/crimson.pdf
It appears to be complementary bipolar. Are you sure your replacement transistors are genuine parts?
http://www.aufi.co.il/amp/crimson.pdf
It appears to be complementary bipolar. Are you sure your replacement transistors are genuine parts?
The transistors used in attempted repair are off the shelf parts. But substituting transistors from the working monoblock doesn't cure the fault. When I first blew it up the output was completely dead. Output transistors completely toast. A couple of burned out resistors have also been replaced. Now it's working (ish), but after a couple of minutes (if that) it goes unstable.
The fault originally occurred when one of the speaker outputs was shorted against a signal earth on the preamp. The pre is fine.
Schematics to: tom.goldsmith@talk21.com
I'm not actually doing the repair myself, an engineer friend of mine is, but he's well and truly stuck... So if I sound like I don't know what I'm talking about... I'm passing the info on.
The fault originally occurred when one of the speaker outputs was shorted against a signal earth on the preamp. The pre is fine.
Schematics to: tom.goldsmith@talk21.com
I'm not actually doing the repair myself, an engineer friend of mine is, but he's well and truly stuck... So if I sound like I don't know what I'm talking about... I'm passing the info on.
Hi,
my series viii have Brian's name on them.
Can you see the type no. on the outputs 2sa1386/2sc3519?
The 1386 are much less robust than the older 3773 quasi even though their power at 130W cf. 150W suggests closer matching. SOAR is much poorer.
I fear the viii is no longer a true 4ohm amplifier. The 3773 could drive 4ohm easily (domestic not PA duty).
my series viii have Brian's name on them.
Can you see the type no. on the outputs 2sa1386/2sc3519?
The 1386 are much less robust than the older 3773 quasi even though their power at 130W cf. 150W suggests closer matching. SOAR is much poorer.
I fear the viii is no longer a true 4ohm amplifier. The 3773 could drive 4ohm easily (domestic not PA duty).
Crimson Elektrik
Just read the thread about Crimson. I've owned an 1100 for I guess 25 ish years. This is / was a truly awsome power amp.
If you guys have the circuit diagram please send me a copy. My amplifier has worked very hard over the years. But even today I dont think many solid state amps come close. (my brother also has one and he tried to replace in vain.) I dont know what kind of system you guys have. But believe me with some sikorel caps in the PSU and a little filtering near the main boards... well I think you need to spend telephone numbers to replace the amp. If your using the old crimson pre. Then go replace it with something nice. It makes a huge difference driving the amp with a good line amp.
Just read the thread about Crimson. I've owned an 1100 for I guess 25 ish years. This is / was a truly awsome power amp.
If you guys have the circuit diagram please send me a copy. My amplifier has worked very hard over the years. But even today I dont think many solid state amps come close. (my brother also has one and he tried to replace in vain.) I dont know what kind of system you guys have. But believe me with some sikorel caps in the PSU and a little filtering near the main boards... well I think you need to spend telephone numbers to replace the amp. If your using the old crimson pre. Then go replace it with something nice. It makes a huge difference driving the amp with a good line amp.
I have an old Crimson amp from the mid 70's and its starting to hum pretty good.
I took it to a local who claimed to be the guy who brought these to Canada, and an 'expert'. He didn't do anything, but luckily I was able to get my money back.
I'm no electronic tech, but would appreciate a little help in trying to fix this fantastic sounding amp.
It makes me look like a speaker building genius
I took it to a local who claimed to be the guy who brought these to Canada, and an 'expert'. He didn't do anything, but luckily I was able to get my money back.
I'm no electronic tech, but would appreciate a little help in trying to fix this fantastic sounding amp.
It makes me look like a speaker building genius
Hi,
my introduction to DIY was Crimson when it was Elektrik in the mid 70s.
I used the very precise directions given in the comprehensive literature issued at the time (the turquoise A5 booklet). It was wrong! and it was repeated in the later modules bought in the early 80s and late 80s (xeroxed A4 & computer schematic). It took 30years to find the right way.
I am in the process of rebuilding my Crimsons vii, vii imp, viii, the oldest is going to be upgraded to 3004 or maybe 4003 from the original 1704 while the grounding is getting sorted out.
Brian Powell is still around and still designing (as of 2000)
my introduction to DIY was Crimson when it was Elektrik in the mid 70s.
I used the very precise directions given in the comprehensive literature issued at the time (the turquoise A5 booklet). It was wrong! and it was repeated in the later modules bought in the early 80s and late 80s (xeroxed A4 & computer schematic). It took 30years to find the right way.
I am in the process of rebuilding my Crimsons vii, vii imp, viii, the oldest is going to be upgraded to 3004 or maybe 4003 from the original 1704 while the grounding is getting sorted out.
Brian Powell is still around and still designing (as of 2000)
Well if it followed the original instructions the audio ground and the safety earth are connected together.
If they are, they should be separated.
But, keep a permanent safety earth on the chassis.
Fit a disconneting network from safety earth to audio ground.
I think speaker returns go to the module PCB. Try moving returns to audio ground.
The module has power grounds and signal grounds sharing the same traces, I do not think there is anything you can do to significantly improve (separate) this.
The electrolytic caps may have gone high ESR with age and temperature and may need replacing.
Crimson's 1100 kit used just +-4700uF for each of the 1704 modules.
This is far too low.
For 8ohm speakers increase this to about +-10mF and for 4ohm speakers to +-20mF for each module.
If they are, they should be separated.
But, keep a permanent safety earth on the chassis.
Fit a disconneting network from safety earth to audio ground.
I think speaker returns go to the module PCB. Try moving returns to audio ground.
The module has power grounds and signal grounds sharing the same traces, I do not think there is anything you can do to significantly improve (separate) this.
The electrolytic caps may have gone high ESR with age and temperature and may need replacing.
Crimson's 1100 kit used just +-4700uF for each of the 1704 modules.
This is far too low.
For 8ohm speakers increase this to about +-10mF and for 4ohm speakers to +-20mF for each module.
Crimson Eltrik
Both the power amps are Crimson Electrik 35-01B and the pre amp is Crimson Electrik 35-15B. I also have a moving coil preamp 35-17B, but it's unlikely I will use it again. I still have the STD turntable and rega arm but wouldn't dare use the cartridge. To complete the antique line up I also have a goodmans turntable with a parallel tracking arm. Haven't tried either in years. The power transistors are 2N2773 in the amps.
Both the power amps are Crimson Electrik 35-01B and the pre amp is Crimson Electrik 35-15B. I also have a moving coil preamp 35-17B, but it's unlikely I will use it again. I still have the STD turntable and rega arm but wouldn't dare use the cartridge. To complete the antique line up I also have a goodmans turntable with a parallel tracking arm. Haven't tried either in years. The power transistors are 2N2773 in the amps.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.