Rob Karloff Posted February 25, 2004 Report Share Posted February 25, 2004 E-bay, folks. It's a marvellous place Having got pissed with my DSL50 dieing yet again, a mere 11 months since Marshall fixed the last problem (blown output transformer), I decided that I either wanted a backup amp given that I am now somewhat distrustful of my DSL's reliability, or a replacement. Sid Karloff uses and REALLY abuses a 50W JCM800, so I figured that would do me. He's had 8 years of non-stop service from his, despite it being dropped, banged, crashed, and all the other things you aren't supposed to do to a valve amp. Not even a valve failure!So, now I have a 1989 model 2203, for a mere 300. Starting bid was 295, waited until 20 seconds before the end of the auction with no bids..... Whammo! Paid for it and the P&P using PayPal, got it two days yesterday in the mail. Exremely well packed, complete with power lead. The amp is exactly as described, near mint, and is LOUD. I think I'll keep my DSL50, and will decide during a soundcheck whether I want to use it or the 2203 as my main amp. Also going to pull out two of the 2203's power valves to bring it down to 50W, as the output is defening, even at about 0.75 (yes, less than 1!) master volume. Can't wait to try it cranked up though! I also have info on how to bias the sucker properly (want to check it over first pre-gig), and on a host of hotrodding mods involving a few capacitors and resistors soldered in the right places. Hoopla! Quote Link to comment Share on other sites More sharing options...
Tav Posted February 25, 2004 Report Share Posted February 25, 2004 That seems like a pretty fine deal! Hot Rodding amps...you couldn't stick to cars then? If you've got any of those hot rodding tips in PDF or any other form of document I would be very grateful if you could email them my way? I am currently amassing circuit diagrams with the aim of creating my first amp, should be interesting. Quote Link to comment Share on other sites More sharing options...
Rob Karloff Posted February 25, 2004 Author Report Share Posted February 25, 2004 Could do.But....I think you can give up on the idea of building one yourself. Amps have not been handwired since the early eighties mostly, and this is partly to do with the cost saving of using PCBs and computers, but also to do with the sheer amount of components and their connections necessary for any kind of amp that has modern gain amounts, big EQs and things like effects loops and reverb. Also, most diagrams seem to show the core components that aid in biasing and other servicing, but not the complete spec of every component used and their values. Coming up with some of the individual components at a reasonable price is also less than easy, e.g. transformers of the correct specs, valve sockets, large power capacitors. Maplin et al stock lots of components, but not some of those found in amps! The other thing you'll struggle with is making a good chassis to mount the stuff on, and planning and making a good chassis with a good layout of components can make or break an amp design.All that said, if you really think you can do it and come up with something worthwhile, go for it. I'd just hate to go to all that effort and end up with an amp that I couldn't get to work, or something that worked but was crappy and unsuitable. The knowledge on valve amps and circuitry you'll pick up will be good, but is that really enough? Making good valve amps as a business is hard to do, hence why there are so few manufacturers, and there certainly isn't much money in it!For all your amp schematics, biasing info, hotrodding, etc, go to the Marshall section on http://www.blamepro.com/ and look in the forums. Lots of good info, lots of extremely knowledgable and very helpful amp-headz! Quote Link to comment Share on other sites More sharing options...
*Craig_HexPen* Posted February 25, 2004 Report Share Posted February 25, 2004 sounds like a beast ....i dont even own a working guitar amp Quote Link to comment Share on other sites More sharing options...
Tav Posted February 25, 2004 Report Share Posted February 25, 2004 Cheers for the link Rob I'll take a look at it later. I see you have raised many good points there most of which I have thought about. PCB's won't pose a problem currently with the amps I am starting to build and hopefully once at uni I can get access to some PCB making facilities and if not I will have to look else where. I have got many full schematics of many different models/makes <vox, hi-watt, marshall, orange, mesa, ampeg amoung others> of amp. The amount of components doesn't worry me at all as amps still revolve around the same designs and components bar a few fancy inclusions. As for the chassi I can get the right size for what I am doing currently online and when the time comes I can get some made up for me in family if needed. I am starting small and working my way up. First project is a 5-7watt practice combo with a 12AX7A pre amp and a EL84 output section, I've heard another persons attempt at making this amp and it sounds very good for simple design. After that I will start working my way up the power and add various features. You raised a good point about there not being alot of money in it which would cause a problem if you were looking for that but currently this is just a hobby to expand on the knowledge I have gained in advanced higher tech and incorporate my interest in music and gear. Quote Link to comment Share on other sites More sharing options...
Rob Karloff Posted February 26, 2004 Author Report Share Posted February 26, 2004 Cool Start small and work up is definately the way to go. Even a basic amp will teach you the main things such as core components and sections, how they interact, and how to set them properly. I'll be very interested to see how you go! Take good heed of the warnings about lethal voltages in valve amps though, whether building one from scratch or just servicing an existing model. Some of those big power capacitors store around 450V, more than enough to launch you a good few feet across the room at least, or kill you at worst. Check out those forums, as there is some good, reliable info on how to discharge and monitor these babies when working on a valve amp. Quote Link to comment Share on other sites More sharing options...
Tav Posted February 26, 2004 Report Share Posted February 26, 2004 Originally posted by Rob Karloff:Cool Start small and work up is definately the way to go. Even a basic amp will teach you the main things such as core components and sections, how they interact, and how to set them properly. I'll be very interested to see how you go! Take good heed of the warnings about lethal voltages in valve amps though, whether building one from scratch or just servicing an existing model. Some of those big power capacitors store around 450V, more than enough to launch you a good few feet across the room at least, or kill you at worst. Check out those forums, as there is some good, reliable info on how to discharge and monitor these babies when working on a valve amp. Yeah the whole lethal voltage aspect is going to require some extreme care but I have managed to find articles on how to discharge components properly and aslong as you are sensible things shouldn't go wrong...can always wear a big set of silly rubber gloves! Once I have got my first one up and running I shall post up some pics and sound clips. Quote Link to comment Share on other sites More sharing options...
Jeid Posted March 1, 2004 Report Share Posted March 1, 2004 after 1986 or 1987, i can't remember, 2203's went downhill as they started using PCB's. the best ones were made before this time, and they have the "true" valve sound.well done though Rob. i'm sure your gonna love it regardless. i'm just picky when it comes to 800's. i'd have to get an original pre 86 one Quote Link to comment Share on other sites More sharing options...
Rob Karloff Posted March 1, 2004 Author Report Share Posted March 1, 2004 Originally posted by Eriatarka:after 1986 or 1987, i can't remember, 2203's went downhill as they started using PCB's. the best ones were made before this time, and they have the "true" valve sound.well done though Rob. i'm sure your gonna love it regardless. i'm just picky when it comes to 800's. i'd have to get an original pre 86 oneAs I understand it, only a very few of the first serie of JCM800 were made without PCB. Certainly, every 2203/2204 used PCB construction (still largely hand wired tho), and even though the later 800s used PCB they still used the exact same circuitry as the earlier models. When they changed to the master volume series, they changed a few things and introduced the 2203/2204 sub-classes. When I crank my 2203 (a painful, but not unpleasent, act) I get an AC/DC sound without distorto-pedal, and anything to Slayer with it. Sounds pretty "valve" to me I'm also told, that as long as you go for an original run 2203/2204 (not the current re-issues) and don't go for the dual-channel variant, you'll get the best of the Marshall pre-amp gain developments with none of the tone/reliability problems of the later and dual-channel variants.Mine sounds killer already, even on the current unbranded valves. I will re-valve with JJ/TESLA valves I think, based on current prices/reviews/etc.Marshall also tell me that output transformer #3 has decided to die in my DSL50, along with a couple of valves also on their way out. I've told them to fix it and test it as much as they can before sending it back. Either there is some inherent problem with it's innerds that is causing it to slowly chew through OTs, or Marshall need to use beefier units. If it goes again at any point, I will source a suitable aftermarket transformer and valves. But, I may decide to use the 2203 as my primary amp anyway. Quote Link to comment Share on other sites More sharing options...
Jeid Posted March 1, 2004 Report Share Posted March 1, 2004 use the 2203 as your primary amp!or be a rock star... buy another cab and use both Quote Link to comment Share on other sites More sharing options...
Rob Karloff Posted March 1, 2004 Author Report Share Posted March 1, 2004 I will only buy another cab once I've moved to a house of my own due to lack of space, but hopefully that won't be much longer! Never yet played anywhere that's been big enough to warrant more than 1 cab anyway, let alone more than one amp head. I will be spending a good bit of time comparing and contrasting the amps though. Quote Link to comment Share on other sites More sharing options...
Jeid Posted March 1, 2004 Report Share Posted March 1, 2004 i got kris to do it at drummonds once. it was awesome.Vox AC30, DSL50 into 2 4x12's.... Quote Link to comment Share on other sites More sharing options...
Ally Boss Koala Posted March 5, 2004 Report Share Posted March 5, 2004 shit, nice deal man. 800s are the shit. fuck the dsl, sell it for drug money, the 800 is a real mans amp. Quote Link to comment Share on other sites More sharing options...
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