see if I can improve it. Anyone got a schematic or a circuit diagram, mine have long gone 
Hi,
I have the schematic for VII and VIII (the 2002 version).
For tweaking the series VII just update it to series VIII, but you will need to saw off the end of the pcb that is currently under the heatsink angle and hardwire the new output transistors into the old board. You also need to review the RC time constants around the feedback loop and input hipass. The circuit responds well to plastic decoupling caps everywhere and a beefy PSU. I use +-20,000uF per rail (total 80,000) and 625VA transformer.
The old 2n3773 had excellent SOA upto 100v most new transistors cannot match them so you may want to consider doubling up the outputs. Series 8 pcb is already drilled for 4 outputs with emitter and collector resistor positions.
Finally, output of VIII is fully complementary using darlington shiklai (CFP) after the predrivers.
Email me, I might be able to digitise the schematics (photo) or else post them.
regards Andrew T.
I have the schematic for VII and VIII (the 2002 version).
For tweaking the series VII just update it to series VIII, but you will need to saw off the end of the pcb that is currently under the heatsink angle and hardwire the new output transistors into the old board. You also need to review the RC time constants around the feedback loop and input hipass. The circuit responds well to plastic decoupling caps everywhere and a beefy PSU. I use +-20,000uF per rail (total 80,000) and 625VA transformer.
The old 2n3773 had excellent SOA upto 100v most new transistors cannot match them so you may want to consider doubling up the outputs. Series 8 pcb is already drilled for 4 outputs with emitter and collector resistor positions.
Finally, output of VIII is fully complementary using darlington shiklai (CFP) after the predrivers.
Email me, I might be able to digitise the schematics (photo) or else post them.
regards Andrew T.
Hi Andy, Any chance you could send a copy of the crimson info to me as well. I'd be interested to have a look see. I still use my CK1100 still going strong despite the use it gets. I guess I must have bought my kit about the same time you did. I used to work near to the Crimson workshops. They were a friendly lot, always had time to talk...
Hi,Simon Ward said:
the CK1100 was the first Crimson I bought. I got an A5 turquoise booklet with it. Didn't you?
It and the later schematics had bad advice on grounding and I always had a little residual hum & buzz with it. It wasn't until about 20years later that I discovered where they went wrong.
All my later versions came with photocopied assemply and schematic. Except series Viii which I had to reverse engineer, to see the similarities over twenty five years of development.
Email me with your requirement.
Thanks Andrew I cant mail you because I'm still under moderation.. I didnt get a nice booklet I got 5 sheets of A4 with step by step assembly instructions and a drawing showing the wiring runs. I've never had a problem with the thing from the day I built it up until last summer. One of the input transistors got a little noisy. Never had problems with mains hum / noise as a stand alone Amp. But had on rare occaisions had to disconnect Earths..
My problem at the moment is that I worry how long this thing will live for before it gives up. I have replaced the 4700uf Capacitors with low ESR Sikorel's. Also put filter next to each pcb supply connection. That made a simply massive difference to the mid range clarity and stiffend up the bottom end a little. I tried driving the amp with a good op amp line amp and a EAR valve line amp (the later giving nice warm midrange). but not being altogether happy I built the air guitarest (naim clone but nicer parts and better earthing). They really go well together very musical etc... My problem is what do I build to replace it without breaking the bank ?
I thought it would be nice to get hold of a copy of the circuit. I could always try building a new one and try tweaking it. My boards do have the 2N3773 output transistors. Certainly stood up well over the years. Even survived the heatsink thermal trip on occaisions.
I thought it would be nice to get hold of a copy of the circuit. I could always try building a new one and try tweaking it. My boards do have the 2N3773 output transistors. Certainly stood up well over the years. Even survived the heatsink thermal trip on occaisions.
Hi,
the CK1100 used the 1704 vii. They did not have the full protection fitted to the series 7.
I don't think the vii had a thermal trip.
fitted with IV protection and a transient slow down and an HF trip as far as I can tell.
I will not post here since the circuit belongs to Crimson or Brian Powell.
the CK1100 used the 1704 vii. They did not have the full protection fitted to the series 7.
I don't think the vii had a thermal trip.
fitted with IV protection and a transient slow down and an HF trip as far as I can tell.
I will not post here since the circuit belongs to Crimson or Brian Powell.
The biggest improvement in sound quality I made with many mods to my Crimson Elektrik 100 watt CK1010/CK1100 kit was replacing one of the signal electrolytics with a large film. The main problem was that there was no DC across this coupling cap. It's a long time ago and I've replaced many caps, so the old memory plays a few tricks, but I think it was the cap coupling the pre-amp outputs to the power amp inputs. A few DVM measurements should find the culprit. Improvements were to HF clarity and 3D spaciousness/image depth.
Second biggest improvement was decoupling and regulating (LM317/337) the +-15v supplies to the pre-amp. Bass and midrange improvements here.
It's still going strong and sounds great with my ancient Castle Conway 2's.
Second biggest improvement was decoupling and regulating (LM317/337) the +-15v supplies to the pre-amp. Bass and midrange improvements here.
It's still going strong and sounds great with my ancient Castle Conway 2's.
Hi,
I've recently picked-up some Crimson Elektrik kit - a pair of 1704s and a CPR(?) pre-amp. Some basic info came with these but what would be really helpful would be the circuit schematics and an explanation why Crimson state "Under no circumstances place a fuse in the positive supply line" (of the 1704s).
Dennis
I've recently picked-up some Crimson Elektrik kit - a pair of 1704s and a CPR(?) pre-amp. Some basic info came with these but what would be really helpful would be the circuit schematics and an explanation why Crimson state "Under no circumstances place a fuse in the positive supply line" (of the 1704s).
Dennis
Here is the VII schematic:-
http://homepage.ntlworld.com/bepowell/schematics/VII.pdf
We do occasionally supply newer PCBs.
Regards
Brian Powell
Designer for Crimson
http://homepage.ntlworld.com/bepowell/schematics/VII.pdf
We do occasionally supply newer PCBs.
Regards
Brian Powell
Designer for Crimson
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