Count Bassie Posted July 31, 2022 Share Posted July 31, 2022 (edited) I'm about to pick this old tank up locally, and want to see if I can find a user manual for it. British Audio Service here in the states has no listing for one, and I know this older stuff gets swallowed up in the mists of time and the quiet chaos of progress. Anybody know where I can find one? AH 250 GP11, Mk IV? Thanks for your time! Edited July 31, 2022 by Count Bassie Quote Link to comment Share on other sites More sharing options...
BassBod Posted August 1, 2022 Share Posted August 1, 2022 Never really seen one, but there aren’t huge differences between MIV, V or Series 6. Watch out for XLR speaker outputs and worn out fans. The ECI light shouldn’t flash in normal use, but will pulse when you power down. The XLR input isn’t balanced, it’s just a parallel option because they thought it was better than jacks. Plenty of experienced users here, so ask away if anything isn’t clear. 2 Quote Link to comment Share on other sites More sharing options...
Count Bassie Posted August 2, 2022 Author Share Posted August 2, 2022 (edited) Thanks BassBod I may be popping in with some. (Okay here's one!...) This one appears to have had the UV light jig removed, she's in a strange condition that I can't discern. Any thoughts here?... I have sent a message to the original owner about this, I'm awaiting reply. Edited August 2, 2022 by Count Bassie Quote Link to comment Share on other sites More sharing options...
BassBod Posted August 2, 2022 Share Posted August 2, 2022 Looks to me that the original case was removed, and the preamp unit and power amp unit were re-housed in a 19” rack box, but in an unusual way! Wouldn’t be hard to re-mount it all back into a 2u wooden sleeve, without the uv light box. The preamp has slightly odd hole spacing for the rack mount screws, but the rear power amp section would need holes drilled in the top to fit the existing bolt locations. From memory there is only one cable/connector between them, so no problem there. Probably worth taking it all out, getting it powered up and seeing how it’s all working before making any decisions. 1 Quote Link to comment Share on other sites More sharing options...
BassBod Posted August 2, 2022 Share Posted August 2, 2022 Quote Link to comment Share on other sites More sharing options...
BassBod Posted August 2, 2022 Share Posted August 2, 2022 From your photo, it could originally have been either the AH150 or AH250? If the power amp section is taller than 2u, then I guess it was the 250… Quote Link to comment Share on other sites More sharing options...
Count Bassie Posted August 2, 2022 Author Share Posted August 2, 2022 Sounding like a bit of work, but, as we say round here, I know a guy... Thank you for your help here! Quote Link to comment Share on other sites More sharing options...
Downunderwonder Posted August 3, 2022 Share Posted August 3, 2022 The amp bit might even be inverted. Quote Link to comment Share on other sites More sharing options...
Count Bassie Posted August 3, 2022 Author Share Posted August 3, 2022 3 hours ago, Downunderwonder said: The amp bit might even be inverted. That's kind of what I was thinking... And it looks like the UV light cover is upside down as well, mounted at the top of the rack. It just looks a bit weird, like someone did something to it. It would be kinda fun to rescue it. Quote Link to comment Share on other sites More sharing options...
Downunderwonder Posted August 3, 2022 Share Posted August 3, 2022 55 minutes ago, Count Bassie said: It would be kinda fun to rescue it I wouldn't risk it. Fixing what isn't broken can lead to heartbreak. You know it's going to pound your kidneys when you plug it in! Quote Link to comment Share on other sites More sharing options...
BassBod Posted August 3, 2022 Share Posted August 3, 2022 Pretty sure the power amp/back plate has been mounted into the top of the rack box, 90 degrees out of its normal position, behind the preamp and face plate. Why? Probably because the preamp is pretty much 19” 2u format, but the back is roughly 3u but not standard 19” format. The uv section sat underneath the preamp, and made up the extra 1u space..but I can’t see it in the photo. Makes you wonder what actually happened to the original wooden case 😳 1 Quote Link to comment Share on other sites More sharing options...
Count Bassie Posted August 3, 2022 Author Share Posted August 3, 2022 1 hour ago, BassBod said: Pretty sure the power amp/back plate has been mounted into the top of the rack box, 90 degrees out of its normal position, behind the preamp and face plate... ...Makes you wonder what actually happened to the original wooden case 😳 Ok, interesting, the seller hasn't addressed any of my questions about this at all. Quote Link to comment Share on other sites More sharing options...
Count Bassie Posted August 3, 2022 Author Share Posted August 3, 2022 5 hours ago, Downunderwonder said: I wouldn't risk it. Fixing what isn't broken can lead to heartbreak. You know it's going to pound your kidneys when you plug it in! Yeah, it's just kinda bizarre to look at... Quote Link to comment Share on other sites More sharing options...
Downunderwonder Posted August 3, 2022 Share Posted August 3, 2022 10 minutes ago, Count Bassie said: Yeah, it's just kinda bizarre to look at... Blank plate, job done. Quote Link to comment Share on other sites More sharing options...
BassmanPaul Posted August 3, 2022 Share Posted August 3, 2022 Personally I wouldn't risk it. Damage you can see has no bearing on what is unseen! Quote Link to comment Share on other sites More sharing options...
Count Bassie Posted August 3, 2022 Author Share Posted August 3, 2022 11 hours ago, Downunderwonder said: Blank plate, job done. Fair enough. Quote Link to comment Share on other sites More sharing options...
DGBass Posted August 4, 2022 Share Posted August 4, 2022 As far as schematics go, the old MkII and MKIV GP7/11 versions don't seem to be available anywhere I can find. The Power amp chassis though is pretty much the same as in the more readily downloadable (online) MKV AH250/350/500 schematic so that at least will make any maintenance on the power section possible. I rebuilt a MKV AH250 during lockdown and the amp section does hang "upside down' normally and there are three cables from it to worry about. The main power amp signal cable and power feed for the GP11 front panel pre-amp which is usually a square plastic multi plug that can only fit one-way and the two 110V blacklight connecting plugs. I messed about with trying to fit mine all in a 3U or 4U flight case but it was easier fixing up the original 3U wooden sleeve despite it being damaged. The power sections are heavy beasts and the 4U case I intended to use wasn't structurally heavy duty enough to cope with having the power amp chassis bolted in upside-down like it is as standard. I tried and it rattled in the case a lot. 3U cases seem much harder to source these days except if you are willing to pay a bit more for one or to have your AH250 GP11 professionally installed in a custom made rack case. They are killer amps and nothing much goes wrong with them apart from worn graphic sliders especially if they are the earlier white plastic ones. The blacklight doesn't usually give much problem either as long as the 110v tube starter is replaced periodically and of course the blacklight tube does wear out eventually after 30 or so odd years of service 🙂 I suppose cosmetics don't matter too much as long as you are happy with the performance aspect. It's always good though to see one of these on stage with that blacklight glowing away and illuminating the green goodness of the pre-amp. You know you've arrived when you feel one of these AH units behind you on stage. 3 Quote Link to comment Share on other sites More sharing options...
Count Bassie Posted October 7, 2022 Author Share Posted October 7, 2022 Well the thing was still available, so I'm arranging to get it shipped, and I'm bringing it to an electronics engineer/amp tech friend. I'm going to go for it, get it back to it's original orientation. I know, it may not be the favored rec among some, but I'm sure it's possible. This guy's very good... I'll post as it goes. Quote Link to comment Share on other sites More sharing options...
BassBod Posted October 7, 2022 Share Posted October 7, 2022 Best of luck….it’s solid old tech, so there’s a very good chance it can be restored to a good standard. Don’t forget Ashdown have a very good service team and know a lot about old TE. Worth an email if there are any mysteries 😜 1 Quote Link to comment Share on other sites More sharing options...
Count Bassie Posted October 7, 2022 Author Share Posted October 7, 2022 1 hour ago, BassBod said: Best of luck….it’s solid old tech, so there’s a very good chance it can be restored to a good standard. Don’t forget Ashdown have a very good service team and know a lot about old TE. Worth an email if there are any mysteries 😜 Great idea, thanks! Quote Link to comment Share on other sites More sharing options...
TheGreek Posted October 7, 2022 Share Posted October 7, 2022 4 hours ago, BassBod said: Don’t forget Ashdown have a very good service team and know a lot about old TE. Worth an email if there are any mysteries 😜 Exactly what I was going to suggest. 1 Quote Link to comment Share on other sites More sharing options...
Count Bassie Posted October 8, 2022 Author Share Posted October 8, 2022 One last thing, do any of you happen to have one of these old MK IV or MK V heads on hand? If it were convenient, would you mind running a measuring tape too the inside dimensions of the plywood sleeve? I'm going to have to build a new one for this poor old thing. And I realize you'll probably have metric numbers, I'll just convert them to English- I mean American- numbers. Thanks! 🤪 1 Quote Link to comment Share on other sites More sharing options...
Count Bassie Posted October 14, 2022 Author Share Posted October 14, 2022 The amp arrived yesterday. It's a little more of a pile than I was expecting, not mounted in a case like I was expecting- but there price was right. I've got communication back from Dave at Ashdown and he's been friendly and forward about offering help and knowledge. My local guy got an email with the photos here, I'm waiting to hear back from him. His response may be interesting, lol. Here's the pile... Woot! 😂 Quote Link to comment Share on other sites More sharing options...
BassBod Posted October 14, 2022 Share Posted October 14, 2022 The bigger AH250 in this photo is probably what you've got there...should all fit in 3u wooden rack case, but the power amp on the back plate is heavy and will need to be mounted carefully to be secure. Best of luck - they are great amps, so its worth a bit of a gamble! 1 Quote Link to comment Share on other sites More sharing options...
Matt P Posted October 14, 2022 Share Posted October 14, 2022 hello, I've just come across this, I have an identical Trace GP11 AH250 head sitting here, happy to help with measurements/ photo's etc to get your amp back into usable condition. Just let me know what information you need. they are a bit of a beast of an amp, the 250W rating is nothing like how they respond on stage, i don't think i've had mine above 2.5 on the master volume (and that was wearing earplugs.) Matt 2 Quote Link to comment Share on other sites More sharing options...
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