Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com

Sound City amp head help

Discussion in 'Glowing Bottle Tube Amp Forum' started by morgansofas, Sep 11, 2017.

  1. morgansofas

    morgansofas Tele-Meister

    281
    Feb 15, 2013
    Sherwood Forest, UK
    Hi all hoping for any info on a Sound City Regent 50 head. I've took a chance on an untested and it worked! It looks like the valves might be original and like it's never been opened. It needs a service and the controls are crackly, also there is some background noise. It 20170910_212704.jpg 20170910_212817.jpg still sounded good though!

    It has a 2xEL34 power section, with 3 preamp valves and a GZ34 rectifier. The valves I can see are made by Brimar. The transformers are beefy too! Aside general info, my questions are:
    Can the two channels be jumpered together like a Bassman? Reverb.com shows a video demo which looks like it is

    There is the option of changing the ohms to 3 or 15 on the back, by inserting pins. Am I right in thinking that without them, the amp needs around 8ohms?
    Thanks folks
     

  2. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    Don't turn it on again. An amp that old - especially if it's been sitting - has crystallized filter capacitors (and likely every other electrolytic capacitor). It might work, but one of those can blow wothout warning and fry the power transformer. This is the type of situation where that most commonly happens.

    You can find a schematic on the web and possibly in the "Tube Amp Book" schematics (I haven't searched the disc yet). They're fairly common amps, with the nickname "Sound Sh**y". NOT considered among the best of 70's/80's heads but sometimes good clean machines.

    But that thing needs service before being powered up again. DOn't take chances.
     
    Wally likes this.

  3. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    Here's a link to SS schematics. FWIW I simply googled "Sound City Regent 50 Schematic". It provided some specific results, but I didn't go through them - you'd likely have to match the electronics in that one itself guts up to one of the schematics for a 50-watter. Most SS schematics don't have "names" on them:

    http://el34world.com/charts/Schematics/files/soundcity/Soundcity_Schematics.htm

    operation won't matter a bit until it's in safe playing shape. If you don't know how to work on amps safely it'll need top go to a tech.

    Plan on about $200-$400 for necessary service if it needs tubes; maybe in the $200 range if not if it's never been touched. This is common with all vintage tube amps, and these are usually a little more involved to service.
     

  4. morgansofas

    morgansofas Tele-Meister

    281
    Feb 15, 2013
    Sherwood Forest, UK
    Thank you for the link and good advice. I have a good amp tech, although not sure if I'll keep it yet. If I do, I'll certainly make sure it is safe.
     

  5. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    Hate to tell you -


    But I seriously doubt that is a Sound City head. Now that I looked at the picture closely:

    1. Every Sound City amp I have ever seen has power *and* standby switches on the front panel

    2. the pasted-on label does not look like any Sound City label ever made. It looks like a cheap imitation and the letters are the wrong size inside the label itself.

    3. The "3" and " 25 are NEVER seen on a Sound City - not is any kind of connection to some kind of brown board showing through a rough hole.

    4. The controls are wrong. Labeling should be under the controls and "Volume: and "Brilliant Volume".

    5. No Sound City has the name on the far right. There's rarely any name at all - just a number.

    6. Grill cloth could have been removed - but why?

    Everything about it looks wrong, but the "3 & 15" (which make NO sense - 4, 8, and 16 would), the controls and lack of standby switch are absolute killers. My guess is it's some cheap Japanese amp with a fake label on it. This was very common in the 70's and 80's - there are tons of "Fenders" floating around that aren't. I find it pretty funny - considering the reputation of Sound Sh**y amps in the 70's/80's...that anyone would bother to fake one. Now they are "vintage" amps and sell for $700 or so.

    Not this one. And the only way it likely can be serviced is by a knowledgable tech that can work without a schematic - which means any qualified amp tech.

    I could be wrong. But I doubt it.
     

  6. morgansofas

    morgansofas Tele-Meister

    281
    Feb 15, 2013
    Sherwood Forest, UK
    I wondered about the label too. Not disputing any of your comments, but I had an old valve amp and a Fane speaker that had 15ohm ratings, maybe an old British value? The same amp as this on Reverb.com was listed as a Sound City, but had no label. Looking at the cab construction, it is very similar to Carlsboro cabs of the same age, and the transformers look like the Partridge ones I've seen in contemporary UK amps.
     

  7. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    I think you are mistaken and both had 16-ohm ratings. 15 ohm markings on even one of the two would be very odd. 16 ohm settings or taps are commonly found on Marshalls and others, but 15-ohm guitar amp cabinets are just not found - anywhere - on the commercial market. There are no speakers to make the math work out (unless you wired up a few dozen or something).

    :confused:

    PS - you might look closer at that "15" - see if it's actually "75". If so you have a hi fi amp and that's an antenna connection. The mystery would be - where's the tuner?

    I'm not sure those are speaker connections at all.
     

  8. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    I did a little digging, and the only Sound City amps with similar controls and switch (but not jacks) were cheap SS bass combos - no heads, no tube amps and the switch/pilot are different.

    There are similar Regent combos, but the only ones I can find are, again, solid state. And no "50's"...

    ...and all were made in East Germany. :eek:

    So I think I'll stand by my "not a Sound City" thought....
     

  9. Dacious

    Dacious Friend of Leo's

    Mar 16, 2003
    Godzone
    15 ohm was the old British/Commonwealth standard. Goodmans Audioms are 15 ohms. I've had 3 Aussie PA 100 volt line output heads with a 15 ohm test outlet. It's why Vox and Marshall and Celestion their major supplier mostly used 16 ohms, it being 'close enough' and I think they started remarking them in the 60s when Exports started to the US to align to audio standards there.

    Having said that, the output selection looks like a Bird Co UK voltage selector. I wouldn't mind getting it's a vintage UK or Euro amp.of some description someone's stuck the labels on. There were a lot of little oddball makers, cottage industries there.
     

  10. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    Yeah, seen that before as a test point and on "hifi" speakers like Goodmans (and on some Celestions) but didn't consider those thoughts relevant in this context as I don't recall any amplifiers with those two markings at all. "15" is simply not found as a speaker connection on any common guitar amplifier, nor that type of connection board (dual banana jacks normally plug into posts on bass amps)...nor with "3-ohm" anything.

    Not sure what you mean by "It's why Vox and Marshall and Celestion their major supplier...". That's 3 companies - supplying who? Goodman "Audiom" are speakers, so they wouldn't be supplying Celestion. And Vox and MArshall...err...

    I'm confused! :D
     
    Last edited: Sep 12, 2017

  11. VintageSG

    VintageSG Tele-Afflicted Ad Free Member

    Mar 31, 2016
    Huddersfield, UK
    Here's your amp.


    RSC kit amp?
     

  12. Dacious

    Dacious Friend of Leo's

    Mar 16, 2003
    Godzone
    Yup I was thinking that. Seen a lot of SS kit amps with those components.
     

  13. Dacious

    Dacious Friend of Leo's

    Mar 16, 2003
    Godzone
    I mean Goodmans (and Celestion and Whardale) supplied 15 ohm audio speakers 50s and 60s. Some vintage AC10s came with Goodmans. Early amp makers made to suit components on the market. Things like Selmers came with those little oval speakers. I'm only surmising this.

    I think it's an arcane standard that they arbitrarily changed probably to align with US, where amps and speakers came with 4,8,16. I do have a 62 red magnet Wharfdale marked 4ohms.

    I read in some brand's history could have been Mackintosh that for hi-fi 16 (15) was considered optimal because the length of the voicecoil ditto winds in the output secondary meant lower current and less heat; meaning greater fidelity at high khz. Of course for guitar, not so important.

    We had guitar amp kits here in Oz for ETI electronics magazine which used 6DQ5A and 6DQ5B Television sweep tubes. I think the OT was 4400 ohms/15. They also made stereo kits . Probably same components. Here one from their last 1980 magazine. 4 EL34s - 140 watts. This isn't a guitar amp, home theatre or cinema
    eti456physical.jpg
     
    Last edited: Sep 12, 2017

  14. radiocaster

    radiocaster Friend of Leo's

    Aug 18, 2015
    europe
    [​IMG]
    Not only that, but it's also listed on Celestion's site. As it seems to be a reissue, quite possibly there were other 15 ohm speakers during the original era.
     

  15. morgansofas

    morgansofas Tele-Meister

    281
    Feb 15, 2013
    Sherwood Forest, UK
    Thanks everybody, some great knowledge shared. I spotted the demo video too, thanks for that.
     

  16. fenderchamp

    fenderchamp Tele-Holic Ad Free + Supporter

    672
    Jun 17, 2008
    omaha
    they guy from the video, is selling the one in the video on reverb.
     

  17. morgansofas

    morgansofas Tele-Meister

    281
    Feb 15, 2013
    Sherwood Forest, UK
    I think it sold for around $450
     

  18. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    65
    Mar 2, 2003
    Lawndale CA

    Yeah, we were good at shipping you our unwanted junk...

    :lol:

    ...just kidding. I'm aware of odd things like that - but not on a Sound City amp, ever. Nor was that type of connection used, nor a "3 ohm" tap. That was my point. It's *way* out of "Sound City" context.

    Many Celestions are marked 15 ohms, and other speakers "15/16". But again (I hope I don't need to say it any more) Sound City amps are NOT marked that way, nor with a "3". Nor any other common guitar amp. And the entire back panel as shown looks wrong - the extra hole, the holes next to the "3/15" panel (does it actually read 15?), the bare fiberboard......

    It looks vaguely like a solid-state Sound City or East German box with a different chassis stuffed in it - again, the standby switch found on sound City tube amps is missing, the switch/pilot are in the wrong place, the jacks don't look right the single speaker connection seems wrong (there are usually 2), why is there a jack *and* the weird "3/15" banana plug jack, and why the odd "non Sound City" logo pasted on the front?

    Virtually everything except the tube complement and general "logo-top/controls-bottom" looks very wrong.

    Any chance we can see the circuit board and top of the amp (transformers and tubes)? Transformer codes would be interesting as well.
     
    telemnemonics likes this.

  19. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    I did searches that pull up sold items on reverb and saw Sound City 50 heads - but none with 4 controls and power-only switch.

    Are you sure it was the *same* amp? I went through all my old files and there's no Sound City "Regent 50" nor any tube head with that front panel arrangement.
     

  20. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    I'm still curious about the "15" (whether that's actually what it reads) and if we can see chassis/transformer pictures - but meanwhile, here's the Sound City information page link for you. Unfortunately your head just doesn't match anything in the Sound City line. There is no "Regent", and there's also this:

    "my Sound City amp has output transformer taps for 4, 8, and 16 ohms as well as a tap labeled "100V." Can I use the 100V output as a line output?"

    Pretty clear that "3/15" and one /14" jack with no impedance switch are flat wrong.

    http://soundcitysite.com/faqs.htm

    ...and this is a typical Sound City 50-watt head's back panel. Absolutely everything about it is different.

    [​IMG]

    Part of the reason for seeing the chassis pictures is to try to figure out roughly what it *really* is. It may be odd, but it might be a decent guitar amp! It'll take a tech visit to truly determine how useful it is (we can't check plate voltages and such over the 'net) but some of the gang here may have a general idea.
     

IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.