Schematic for AH600SMX

[ianrendall]

I’m soon purchasing a Trace AH600SMX off a friend for the princely sum of £150. 

As far as I know it’s in full working order, apart from the DI which is apparently doing ‘funny’ things. I rarely use DI, maybe once a year at the ‘big’ gig under Concorde 002, but I’d still like to have it 100% 

I won’t know the full extent of the problems for a few days until I get it, but until then, I’d like to study a schematic or technical manual to get familiar. Where to get? I can find lots of pdf files for various models but not the AH600.

I’m handy with a soldering iron and my father is a retired electronics engineer so it’s within my abilities to fix. 

[ikay]

This (old) TB thread mentions that British Audio Services (Nashville) sell a CD which includes the AH600SMX schematic for $15. May be worth contacting them if you can't find it elsewhere.

https://www.talkbass.com/threads/need-schematic-for-trace-elliot-ah600-smx.389111/

Or try a UK Trace repair centre such as https://www.proaudioservice.co.uk/bass-amplifier-repair/

[whizzzy]

This doesn't directly answer your request for a schematic for the AH600SMX but you can download schematics for other Trace amps here . I have looked at the DI stage in the GP12X pre-amp circuit and it looks a fairly standard configuration using two halves of a TL072 op amp. Then looking at a schematic from an Ashdown amp this configuration seems almost identical so I would hazard a guess there is a fairly strong chance that the AH600SMX isn't going to be too different to this.

That may help to give you some pointers in the absence of the actual circuit diagram.

[ianrendall]

Thanks for the answers chaps. I’m not sure a circuit diagram is actually necessary now I think about it. We have all the electrical testing equipment we need in my workshop, and any non-Trace specific duff components should have the part number stamped on in case I need to order from CPC. 

[ianrendall]

Is the valve in the pre a 12AX7 as per?

[Deedee]

Did the DI on this lovely SMX require a repair or was it ok?

 

[ianrendall]

On 29/04/2018 at 22:38, Deedee said:

Did the DI on this lovely SMX require a repair or was it ok?

 

I couldn’t see anything wrong visually. I don’t have the means to test the audio output at the moment, so all I’ve done for now is tested connections and cleaned the pins with contact cleaner. And they were filthy. I rarely DI, maybe once a year. If it doesn’t work I’ll just have to turn it up to 4. 

Edited April 30, 2018 by ianrendall

[Deedee]

Just now, ianrendall said:

I couldn’t see anything wrong visually. I don’t have the means to test, so all I’ve done for now is cleaned the pins with contact cleaner. I rarely DI, maybe once a year. If it doesn’t work I’ll just have to turn it up to 4. 

Haha.  Should do the trick!

I’m in the same boat at the moment i.e. no means of testing the DI in the gorgeous MkIV AH250 I recently picked up (until our next rehearsal).  A mate has a small mixer that I should be able to borrow to hook up to see if there’s a signal.