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SWR Fan Club
- Thread starter iriegnome
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The old SWR amps aren't too hard to figure out, schematics are available on line (for free). The first place to start is to isolate it to the power amp, or the pre amp. Plug your bass into the amp and run a line from the preamp out to your markbass head. If your preamp is working you will hear your bass. You can also run your bass into the markbass and out the preamp out of it to the power amp in on the 220. You will easily be able to determine if it's the preamp or power amp section. The older amps sometimes will have soldered wires break off of input/output jacks. I had a 220 once that the wire from the preamp out jack to the power amp in broke, simple fix. If you isolate to the preamp, have you tried a new tube? Another 220 I had the circuit board connection to the master volume pot broke, the circuit board didn't have good support and the pot worked free. I had to look a bit for the pot, but agaiin an easy fix. Let me know what you find, I love fixing SWR amps
I've fixed two redheads, two 220s, and an Electric Blue. Fun fun fun
Another 220 I had the circuit board connection to the master volume pot broke, the circuit board didn't have good support and the pot worked free. I had to look a bit for the pot, but agaiin an easy fix. Let me know what you find, I love fixing SWR amps
Thanks! I did your Pre Amp out test and got nothing. Even though the tube is lighting up the problem is there. When I move the Main Volume or pull out the Transparency knob I get noise, so I think the Power side is working. Removing the top I found that any movement of a 3 wire group of wires from the right side(Viewers side) of the main circuit board to the lower back of circuit board behind the heat sink attached to the 4 transistors causes loud crackling. The 3 wire set is White, Gray & Red and hooks up somewhere under the main circuit board on the right side(Viewer's right). My question is: The best way to get to the under side of this main circuit board is to remove the 4 screws attaching the front face(with all the knobs and input jacks) and titling it forward, instead of removing the bottom of the amp, right? I suspect the red wire is loose there, but all the screws on the bottom cover plate of the amp make removing it seem more difficult than freeing the front panel. Do you agree? Thanks!
BTW- I went to SWR site and did search for a service center near me(I live on HI island of Kauai and usually don't do such things as there is nothing like that around here - maybe on Oahu, but not here). Surprisingly an outfit called "Westside Amp Repair" comes up in Kekaha on the westside of Kauai. But no one is answering the phone there so it is DIY time.
You know, I take my electronic things to a stereo repair place. Just a guy with a very small shop. He is good. Been working with him now for about 15 years. He fixes anything electronic. AND He guarantee's his work. Check around your area to see if you can find someone who fixes stereo receivers and the like. I bet they would be willing to work on your SWR. Also, manuals are very helpful. I always bring the manual with when I bring my amp in for service. Just in case.
Another preamp experiment would be to plug into the Active Input, it bypasses the tube and goes right to the buffer transisters. If you get preamp out signal, then the tube is not working. Just because the lights are on, don't mean anybody's home. Yes the four front screws are the way to peek under the main board. The group of three wires are the high voltage rails (+55V -55V) for the power amp, if you resolder make sure the amp is off and unplugged. The power amp check (run an external signal into the power amp in) will determine if the +/- high volts are driving the output stage. Removing the bottom of the amp is a royal pain, the heatsinks, bridge, transformer are attached. Since your in Hawaii, I'd be willing to come fix it for free, just send me a round trip air fare and I'm on my way
Another preamp experiment would be to plug into the Active Input, it bypasses the tube and goes right to the buffer transisters. If you get preamp out signal, then the tube is not working. Just because the lights are on, don't mean anybody's home. Yes the four front screws are the way to peek under the main board. The group of three wires are the high voltage rails (+55V -55V) for the power amp, if you resolder make sure the amp is off and unplugged. The power amp check (run an external signal into the power amp in) will determine if the +/- high volts are driving the output stage. Removing the bottom of the amp is a royal pain, the heatsinks, bridge, transformer are attached. Since your in Hawaii, I'd be willing to come fix it for free, just send me a round trip air fare and I'm on my way
I did the Active Input test and still got nothing, but the Power Amp In works from an external signal, so the Power Amp is working well. Of those three wires, only the Red one seemed to be not fully soldered in on the main circuit board side. I'll try to solder it better tomorrow. All the other wire connections seem secure. I tried another tube and still no signal. The only other thing I wonder about is the two pairs of capacitors w/ the twisted ends on top located between the pair of large cylinder-type (4700uf, 63V) things on the right back end of the board. Their twisted together ends seem to be corroded. Do all these 220 amps have these pairs of capacitors(or they may be resistors) joined like this?
With airfares heading up into the clouds like the jets bringing in and taking away all the tourist here every day, I don't think I could afford your ticket. Much as I would appreciate the experienced help. We have one small music store here where I almost bought a Red Head SWR amp(it was just the head not the combo amp) a few months back. I might try taking it to them if/when all else fails. But really thanks for all your insights.
Yes all have the resisters mounted like that, the big cylinder things are the capacitors. The SM 400 has a separate power supply board, but has the same setup. Let me think on this today, I have pulled the top on my 220 to try and guide my thoughts. The preamp will be cheaper (as far as components) to fix than the power amp, so that's good.
Count me in. Anyone keeping track of numbers? I think I'm 144. I'm claiming it. If I'm wrong, let me know. I have got an SWR Workingman's tower that I love. I'm pushing it with a GK 1001 RB-II, yeah I know. I almost went with the 750X, but I've wanted a GK for a long time. This cab will rattle your bones!
Just got a Headlite with 2 Golight cabinets - 210 and 115. Plenty of power and easy to dial in a great sound. I really like this stuff.
I traded in a GK MB210 and MBE 115 which I got based on the raves here. The GK just did not perform - not enough volume and not my preferred tones, even after adding damping material like the GK threads suggest.
I traded in a GK MB210 and MBE 115 which I got based on the raves here. The GK just did not perform - not enough volume and not my preferred tones, even after adding damping material like the GK threads suggest.
Some pictures of my equipment.
I used to have a SWR 350 too...
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Could I get a number?
I used to have a SWR 350 too...
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Could I get a number?
I run an 08 Redhead and tried a triad under it for a gig once and was rather disappointed with it. I found that running just about any other 4x10 cab under it achieved much more satisfactory results and moved tons of air. Right now I'm using a brand new Ampeg (classic) svt410hlf cab under it that just freakin' slays em' at their tables!
\m/ \m/
Cool rig. I used to have a BagEnd 1x18 and 2x10 and it was a great setup. How are the effects in the Mo Bass? Been thinking about looking for a Mini Mo for studio use, I don't use effects live except drive, but playing in the studio is a different story. Is the overdrive good? Often wondered why SWR didn't make these available as stand alone pedals.
I like the build-in effects! They are very different from everything else I've used and they sound very warm and "analogue". The overdrive is using a tube (think also used for the pre-amp) so it sounds like a proper warm tube drive but it does cut down the low-end a bit which can be annoying. It's just a matter of taste I guess. Hoewever, you can "add" some dry signal to compansate...
Apparently the Mini Mo is a bit better than the MO, specially the EQ section.
I've got a Workingman's 15 combo. Sure it only has 160 watts without the extension cab, buy I still have gigged with it with my rock music bar band - without PA support at times - and she's kept up with my acoustic drummer and tube amp guitarist. Nice tone too!
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