Searching everywhere for a schematic for my vintage SWR SS-180. Any help would be great... Fender is no help on this one. No records from this era
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SWR Schematic Help
- Thread starter iriegnome
- Start date
- Feb 12, 2006
- 61,086
- 5
- 221,200
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
This is one product that I can't find any documentation on in my archives. I would expect the power amp architecture to be similar to the other early amps (the architecture did evolve) but looking at the early versions of the SM-400 (2 of these modules in this alp) or Studio 220 might be beneficial.
You'd have to search to find all the details but here is how I remember it.
Steve Rabe was an engineer that worked for the original Acoustic Control Corp.
His friend Russ Allee also worked at Acoustic and then started Amplified Music Products in 1981.
Steve desigend the A.M.P 420 amp and this AMP pre-amp:
Groove Tubes SWR All Tube Bass Preamp | Wall Street Studios
Notice how similar the front panel look to SWR (which Steve Started in 1984).
As I recall, Groove Tubes was accross the street from SWR in the early days and they also had a pre-amp that was nearly the same (or the same) as the AMP version.
I have this vague recollection that either SWT or AMP also had an 180 watt amp.
I had a friend who was one of the first SWR dealers and I think my SM400 is from 1985.
I beleive that 400 came out first (it didn't originally have the transparency control) and I think the SM220 was announced slightly later.
I know for a fact that the 220 and 400 use the same preamp.
My suggestion is to get a copy of the SWR SM 220 or 400 schematics and compare to your amp.
Here is the AMP 420 schematic
Invalid Link Removed
Groove Tubes does not list any schematics that are like your amp but they are still in buisness and a guy named Aspen Pitman was in charge during that era.
Here is the SM 400 schematic
I know the bridge rectifier change slightly from the original design.
Hope this helps
Steve Rabe was an engineer that worked for the original Acoustic Control Corp.
His friend Russ Allee also worked at Acoustic and then started Amplified Music Products in 1981.
Steve desigend the A.M.P 420 amp and this AMP pre-amp:
Groove Tubes SWR All Tube Bass Preamp | Wall Street Studios
Notice how similar the front panel look to SWR (which Steve Started in 1984).
As I recall, Groove Tubes was accross the street from SWR in the early days and they also had a pre-amp that was nearly the same (or the same) as the AMP version.
I have this vague recollection that either SWT or AMP also had an 180 watt amp.
I had a friend who was one of the first SWR dealers and I think my SM400 is from 1985.
I beleive that 400 came out first (it didn't originally have the transparency control) and I think the SM220 was announced slightly later.
I know for a fact that the 220 and 400 use the same preamp.
My suggestion is to get a copy of the SWR SM 220 or 400 schematics and compare to your amp.
Here is the AMP 420 schematic
Invalid Link Removed
Groove Tubes does not list any schematics that are like your amp but they are still in buisness and a guy named Aspen Pitman was in charge during that era.
Here is the SM 400 schematic
I know the bridge rectifier change slightly from the original design.
Hope this helps
Your recount of the start of SWR is how I remember it as well. I bought my SS-180 in 1986. Switched to a SM-400 in 1988.. There was a lot about the 180 that was different. The 220 and 400 were very similar. Though the notes I have read state that the 180 became the 400, the 400 came out before the 180. Great information though all the way around. This older early stuff was fantastic gear.
- Feb 12, 2006
- 61,086
- 5
- 221,200
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
Something that might help understand why some of this information is so sketchy and contradictory at times.
When products evolve over a long period of time, and when a company has multiple owners, paperwork and institutional knowledge gets lost and frankly memories fade. I run into this with products I designed 25+ years ago, I just can't remember details unless I go back to the paperwork (which is one reason why I am careful with archiving product docs.) Expand this to 40+ years and multiple owners and the pieces start to fall apart.
When products evolve over a long period of time, and when a company has multiple owners, paperwork and institutional knowledge gets lost and frankly memories fade. I run into this with products I designed 25+ years ago, I just can't remember details unless I go back to the paperwork (which is one reason why I am careful with archiving product docs.) Expand this to 40+ years and multiple owners and the pieces start to fall apart.
Invaluable amount of resources and respect for many people keeping up the archives like yourself
Before SWR was sold to Fender it was sold by Mr. Rabe to his accountant
So, SWR started in 1984, sold to Daryl Paul Jamison in 1997.
Company moved to the Gauss factory in 1999, and sold to Fender in 2003.
Maybe for $8M??
Anyway, according to an original owner's manual for the 1985 SM400, this amps was not changed at all until 1993 and I am nearly 100% sure that was the introduction to the SM400S that had a fan.
You may have what you need with the SM400 pre amp schematic in the earlier thread.
A call to Groove Tubes couldn't hurt for a schematic.
Lastly, check the SWR modification thread (to flatten the frequency response) as there are some really sharp guys on that one and I wouldn't be surprised if Sheldon could shed some light on all of this.
A photograph of you amp guts couldnt hurt either.
"SWR released its first commercial product in 1984, the PB-200 hybrid tube/solid-state bass guitar amplifier. The first 5 units were manufactured by hand in a garage in the San Fernando Valley. This model soon became the SM-400. SWR then pursued development of a speaker cabinet to accompany its amps. In 1986, SWR released the Goliath, a 4 x 10" full-range speaker cabinet with a built-in horn tweeter, a first for bass cabinets.
The company's name was changed to SWR Sound Corporation on 1 December 1997 as part of a restructuring plan. Rabe sold the company to accountant Daryl Paul Jamison and soon created a new company, [Invalid or Expired Link Removed]. SWR was based in Sylmar, California until January 1999, when it moved to the former [Invalid or Expired Link Removed]speaker factory in nearby Sun Valley, California. On 2 June 2003, Jamison sold SWR to Fender Musical Instruments Corporation for a rumored $8 million[citation needed], after a previous year of lagging SWR sales and dwindling market share. Jamison reportedly tried to sell to Fender a year earlier for a larger sum, but this failed to materialize.[citation needed]"
So, SWR started in 1984, sold to Daryl Paul Jamison in 1997.
Company moved to the Gauss factory in 1999, and sold to Fender in 2003.
Maybe for $8M??
Anyway, according to an original owner's manual for the 1985 SM400, this amps was not changed at all until 1993 and I am nearly 100% sure that was the introduction to the SM400S that had a fan.
You may have what you need with the SM400 pre amp schematic in the earlier thread.
A call to Groove Tubes couldn't hurt for a schematic.
Lastly, check the SWR modification thread (to flatten the frequency response) as there are some really sharp guys on that one and I wouldn't be surprised if Sheldon could shed some light on all of this.
A photograph of you amp guts couldnt hurt either.
"SWR released its first commercial product in 1984, the PB-200 hybrid tube/solid-state bass guitar amplifier. The first 5 units were manufactured by hand in a garage in the San Fernando Valley. This model soon became the SM-400. SWR then pursued development of a speaker cabinet to accompany its amps. In 1986, SWR released the Goliath, a 4 x 10" full-range speaker cabinet with a built-in horn tweeter, a first for bass cabinets.
The company's name was changed to SWR Sound Corporation on 1 December 1997 as part of a restructuring plan. Rabe sold the company to accountant Daryl Paul Jamison and soon created a new company, [Invalid or Expired Link Removed]. SWR was based in Sylmar, California until January 1999, when it moved to the former [Invalid or Expired Link Removed]speaker factory in nearby Sun Valley, California. On 2 June 2003, Jamison sold SWR to Fender Musical Instruments Corporation for a rumored $8 million[citation needed], after a previous year of lagging SWR sales and dwindling market share. Jamison reportedly tried to sell to Fender a year earlier for a larger sum, but this failed to materialize.[citation needed]"
- Feb 12, 2006
- 61,086
- 5
- 221,200
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
Not sure how an original 1985 owner's manual could predict that there were no changes until 1993 without some serious time travel...
Confusion, ball busting, or comedy? So hard to tell the difference some days.
SWR printed the original manual and then published an internet version for those that bought the original model. Best I can tell, the difference is just the cooling fan.
- Feb 12, 2006
- 61,086
- 5
- 221,200
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
I would suggest fixing the original problem before modifying anything.
I don't do mod's. I loved the SWR as it was. Original it shall stay. But right on for those who modify their gear to fit their needs.
Look, we know you are a smart amp guy but you're not helping the OP by adding confusion.
What I said was:
SWR Aural Enhancer Bypass
duff2 is Sheldon and he has designed and buit some pretty inpressive pre amps.
Perhaps he has some info on your amp that could help.
He has helped me in the past.
- Feb 12, 2006
- 61,086
- 5
- 221,200
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
But that doesn't address his immediate problem which is operational/functional, so I stand my my recommendation on not modifying ANYTHING until it's operating properly so that you start from a known good condition.
[edit: I see he mentioned that he is not interested in modifying his amp, so that pretty much puts the thoughts of modifying his amp to bed anyway]
FWIW, the SWR history described above is mostly right. Daryl Jamison wasn't simply Steve Rabe's accountant who bought the company in 1997. When SWR Engineering started in the mid-1980s, the owners were Steve Rabe, Daryl Jamison, Ed Randolph, and Richard Robinson, with Steve Rabe owning a controlling percentage. Each had an active role with the business. Over time, Jamison bought out the shares of Randolph and Robinson and, finally, Rabe. When Jamison took over control, he pushed for expansion of SWR Sound Corporation with the goal of selling the business to an MI leader, like Fender or Gibson. As he was fond of saying, "Everything's for sale, even the pictures on the wall." I leave it to others to decide what this meant for SWR.
Last edited:
Thanks for this info.
It sounds like you might know a fair amount of the inner workings.
Did the business grow or become more profitable undr the leadership of Daryl Jamison?
And of course the biggest question:
Did Fender intend to grow the company when they bought them and then changed their minds
or,
Did they buy SWR for technology with the idea of closing it up from day one?
I have a Fender 800 Pro and it does share similarities with SWR including the quasi paramteric EQ, clean studio like tone, a 1 knob compressor that works very well, and a huge amount of power for it's time (1 kW at 4 Ohms). Ironically, the only mention from Fender is this owner's manual.
https://www.fmicassets.com/Damroot/Original/10001/OM_leg_bassamp_800_PRO.pdf
And how about the $8M sale price rumor....
If it were me, I'd call a local tech and see how comfortable he or she might be with the idea of an attempted repair without the manual. By the way, I forgot to mention that the SWR 180 was the 3rd model the produced with the 200 as the first and the 400 as the second.
And the 400 had a "final retail price" price of $1,299 in 1985!
Vintage SWR Products
If unit is completely dead. Usual suspects apply. Basic visual inspection for completely obvious cooked parts. Then if not definitely check fuses and make sure a previous owner didn't have a genius idea of bypassing fuses or putting in some ridiculous value lol. To " fix it" when and if fuses got blown in the first place
There is probably 20 guesses you could assume lol without actually having it in front of you
Power switch , fuse holders. Etc etc is basic stuff if your lucky.
Otherwise basic linear Supply stuff. Cooked rectifiers or high esr or leaky cabs.
There should be a main fuse and 2 amplifier supply fuses. See if there blown or have been replaced with ridiculous values.
Not good make assumptions but usually were talking a cooked output device. Or cooked rectifiers. Simple resistance and diode checks will find those pretty quick.
If output transistor is cooked then it's 50/50 chance the driver transistor went with it. And good idea to check resistor values in the Darlington, compound pair circuits. Likewise the caps can get cooked in the compound pair side. Meaning they look/test okish but values have drifted like crazy after a failure
I've never really seen " bad caps" in SWRs just usually a cooked output device. And possibly driver transistor. Just general run through of passive components on the side that blew.
Don't need schematic as mentioned. And other schematics will help. All very similar ish amps. Big fans of the big chunker 200 series Sanken transistors
SWR Amp Schematics
