Supro Spectator build

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Supro Spectator build

Postby Powdog on Fri Apr 24, 2015 1:03 pm

Hey guys. I'm gonna build a Supro Spectator clone. I have a set of voltage correct transformers from Classic Tone and the schematic that seems to cover a couple of the Valco 5 watt amps from the 50's. Just wondering if anyone else has built one of these, and if any tweaks or mods were necessary. It's pretty low B+ voltages, 5Y3 rectified and 3 x 10uF filter caps. I know Vintage47 was building these for a while but has since discontinued them. I'd like it to be as vintage correct as possible with modern parts and still avoid any stumbling blocks. I sure appreciate any suggestions, experience and build tips. Thanks.
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Re: Supro Spectator build

Postby PeterS on Sun Apr 26, 2015 1:10 am

Cool project. I have a Supro S6606, and looking at the Spectator schemo, they're pretty similar (of course). Main difference seems to be that S6606 has a 12ax7 instead of an octal preamp tube, and the first stage is grid-leak biased. If you're experimenting you may want to try grid leak. I don't think any of the component values or types are all that critical, the end result likely depends as much on what you use for a speaker as anything esle.
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Re: Supro Spectator build

Postby Powdog on Sun Apr 26, 2015 2:19 am

Yea, a couple years back I scored half a dozen '65 Jensen C10N's that had been pulled from Leslie cabinets. Alot bigger magnet than the original C8R's, but they're 4 ohm and in pristine condition. Smooth cones, so they should be warm and crunchy but still have some clean headroom due to the big magnets. Trying to decide weather to use ceramic disc or Jupiter Red Astron caps. With only 3 caps I guess it's pretty easy to try them both. Otherwise I'm gonna stick to the schematic.
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Re: Supro Spectator build

Postby PeterS on Sun Apr 26, 2015 12:19 pm

With only 3 caps I guess it's pretty easy to try them both.


Especially if you just tack them in so they're easy to swap...
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Re: Supro Spectator build

Postby LeonC on Wed May 06, 2015 2:43 pm

Sounds like fun! I love Supro/Valco amps and have built many amps based on Valco designs...but never a Spectator.

Are you trying to build it as a clone, that is laid out and looks like an actual Spectator, or just an amp that has essentially the same circuit design?
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Re: Supro Spectator build

Postby Powdog on Thu May 07, 2015 2:04 am

Yea, I did a layout pretty much like the original, all point to point. The only change was separate filter caps instead of a single cap can. After talking with Terry Dobbs, I resisted the temptation to beef up the filter values and B+ voltage and just went with the original schematic. I have an original Spectator which I drew up a schematic for, just to be sure that it was the same as the Valco 510-11 schematic. I gotta say, Terry was right! This amp sounds amazing. Nothing like the single ended Champs and Maggie's I have. I'm really loving my Double Jet thru the Mic input. The amp is in a Gretschy-style cabinet right now, but I guess I'll have to make a Spectator style cab for it. Those two- tone TV cabs with the big radius corners in the front and back look like such a pain to build and cover. The originals were covered in a book binding type of cloth and varnished. Don't think I'll go that authentic.
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Re: Supro Spectator build

Postby LeonC on Thu May 07, 2015 3:38 am

Ah Cool!! Terry is a good friend and really knows his shit about amps in general and certainly Valco-made amps; he's given me so much great advice over the years.

Yeah, I've got an early 50s National with a cab like what you're describing; it's one of the 5-tube models (all octal preamp tubes) where one of the tubes has the grid coming off a cap on the top of the tube; you've probably seen them.

Totally makes sense to separate the filter sections that way, if you ask me. That's one thing that I do differently from the original 1624Ts in ValClones that I've built.

What did you use for a speaker in your Spectator clone?
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Re: Supro Spectator build

Postby Powdog on Thu May 07, 2015 7:57 am

Right now I have '64 Jensen C10N smooth cone that was plucked from a Leslie cabinet. A little overkill I know, but it was the only 4 ohm 10" speaker I had on hand. I was gonna get a Weber 10F100 which is likely the closest thing to what Valco stuck into these Spectators, but Weber is undergoing some changes, one of which is discontinuing this speaker. Luckily, after pleading with CJ at Weber, he is making me two with the remaining parts they have left. One smooth and one ribbed cone. The original Spectator has an 8" speaker in it, but with the 10" speaker it's actually loud enough to jam with a quiet drummer. I'll post some pics as soon as I figure out how to do it. My brain is sorrowfully analog.
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Re: Supro Spectator build

Postby LeonC on Thu May 07, 2015 2:32 pm

Ah, yeah, I see where you mentioned that up above now.

C10N - love 'em!! Perhaps overkill, sure...but damn, what a great speaker. I have a '61 Supreme that I put one in and that little #^@ker is just crazy loud (pair of 6973s). I get asked to turn it down all the time, unfortunately, but man it sounds great.

In my National Studio 10, I do have one of those 8" Jensen Alnico speakers and those sound great too, in their only little boxy way. I plug that amp into a wet rig and it's loud enough for a drummer who's not a heavy hitter....but there's not much in the way of "clean" there, LOL.

Yeah, pics would be great. Sounds like you've got a great little amp there.
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Re: Supro Spectator build

Postby PeterS on Thu May 07, 2015 9:54 pm

one of those 8" Jensen Alnico speakers


Those seem to be durable too, you see lots of old amps that still have the original. My little Supro has one, and I don't abuse it now, but back when I was a spotty teenager I played it on 10 all the time with a fuzzbox to make it louder... :old:
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Re: Supro Spectator build

Postby Powdog on Fri May 08, 2015 3:06 am

I think my favorite "sleeper" 8" speaker is the Rola alnico Hammond used in their reverb circuits. A little beefier than the Jensen P8R, I use them in my 10 watt ECL86 PP amps. Really a great little speaker...and you can still grab them on eBay for under 20 bucks. I've only seen them in 8 ohm, so not a perfect match for the Spectator OT.
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