My SSS 001 As Built, Corrected Schematics

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David Root
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My SSS 001 As Built, Corrected Schematics

Post by David Root »

I decided to put these out by themselves, if anyone is interested, earlier versions are at the end of Sergio's thread on his SSS, below, but they don't really belong there.

Thanx again to 10thTX for his .sch of my chicken scratch, I finally sat down and plodded thru the editing of his .sch to the best of my ability. I also append an as-built gutshot so you can see the layout, which is nothing like HAD's original. This was basically a prototype without rvb or trem, so I could get the DC coupled driver down and put in some filters.
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Last edited by David Root on Mon Nov 18, 2013 3:55 am, edited 1 time in total.
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mhartman
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Re: My SSS 001 As Built, Corrected Schematics

Post by mhartman »

Thanks David. I admired this build when you showed it way back. Great to see the schem.
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David Root
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Re: My SSS 001 As Built, Corrected Schematics

Post by David Root »

Thanx mh. I have a question. I have some nice RCA 12BH7s and I was thinking about sliding one in as a driver to replace the 12BZ7, to see if it might affect the tone favorably or not.

Since this is a CF, isn't it true that the type of triode is secondary, so just about anything should work electrically speaking? What about current draw in my circuit?
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martin manning
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Re: My SSS 001 As Built, Corrected Schematics

Post by martin manning »

Thanks! A schematic is worth a thousand words!
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dreric
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Re: My SSS 001 As Built, Corrected Schematics

Post by dreric »

Very impressive David.

How does it sound to you?

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Re: My SSS 001 As Built, Corrected Schematics

Post by PaisleyTube »

very cool David

One note: the treble-pot to bass-pot connection is not correct in the schematic
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Re: My SSS 001 As Built, Corrected Schematics

Post by Bob S »

Thanks for posting this great info David.
Sometime next year I'm gonna build an SSS.
The more info I digest, the easier it will be.
Thanks again - great build.
Bob
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Aaron
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Re: My SSS 001 As Built, Corrected Schematics

Post by Aaron »

Very nice. I might have to try a 12BZ7 in my SSS/Odyssey build.

I must say though, that is one hell of chassis! I don't think heavy trannies would be a problem :D

Aaron
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David Root
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Re: My SSS 001 As Built, Corrected Schematics

Post by David Root »

Thanx Aaron, I used the 12BZ7 because it can source more current than a 12AX7, if it ever has to. Not too likely, it is LOUD!

The chassis is a reworked one I did an SLO-60 type build in. It is Allyn's famous Gromet chassis, 1/8" thick. He should have called it The Tank. The OT I used I got from RJ, it's a custom Edcor 100W that weighs almost 10 lb.
The chassis resides in a tubes-up headbox so it's well supported.

Paisley, I just removed the treble defeat switch, otherwise it's as per Bill Dunham's schem. I did notice I am incorrectly showing a 1K8 on the bass stack to ground, that should be 100R. I'll correct that on the schem & repost.

dreric, it sounds very good, clean but with nice harmonic complexity, wide bandwidth, a great platform for a pedal board.

Anyone have anything to offer on my earlier question about changing out driver tubes, particularly 12BH7 instead of 12BZ7?
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Re: My SSS 001 As Built, Corrected Schematics

Post by kaj »

David Root wrote:I decided to put these out by themselves, if anyone is interested, earlier versions are at the end of Sergio's thread on his SSS, below, but they don't really belong there.

Thanx again to 10thTX for his .sch of my chicken scratch, I finally sat down and plodded thru the editing of his .sch to the best of my ability. I also append an as-built gutshot so you can see the layout, which is nothing like HAD's original. This was basically a prototype without rvb or trem, so I could get the DC coupled driver down and put in some filters.
First of all - I`m very impressed of all the good info and schematics I find on this site!! THANKS!
One Q: Can someone pleace explane to me the effect/purpose of the dobble PI-tube section used in the SSS-amps ?? :?:
CHIP
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Re: My SSS 001 As Built, Corrected Schematics

Post by CHIP »

Hi kaj, welcome. It's a cathode follower driver PI. It is an important element of the SSS sound.
Ampeg used this type of PI in their SVT amps.
Do a search on SSS and driver and read up on it.
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mhartman
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Re: My SSS 001 As Built, Corrected Schematics

Post by mhartman »

Thanks again for this David. Just to complete my notes, could you let us know the model and/or specs of the PT and OT that you used on your build?

Thanks, Mike
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crbowman
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Re: My SSS 001 As Built, Corrected Schematics

Post by crbowman »

David,
I'm using a 12AX7 PI with 12BH7 in the cathode driver section on my bastardized attempt at a 50 watt version of the pentode amp. It's got a little over 400v on the plates which scares me a little. However, I've been using it for a couple of months now and have had to crank it up pretty loud a few times for outdoor shows and it seems to be holding up just fine. Don't know how it would fare in a 100 watt build, but I have it from a reliable source that HAD used the 12BH7 in PI CF of the pentode amp.
I will say that the amp sounds really amazing with very tight, detailed, silky low end and absolutely no noise at all, even at high levels.
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David Root
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Re: My SSS 001 As Built, Corrected Schematics

Post by David Root »

Thanx guys.
The PT is a slightly customized BF Twin built by Heyboer. 330-0-330V, 500mA.
3.15-0-3.15V, 7.5A filaments. 6.3-0V 500mA for relays (this PT was designed for a ODS #183 build. Heyboer screwed up and built it as a standup, so I got to keep it free and they built it again as a lay down).

The laminations stack is 1/4" thicker than a standard BF Twin. The sticker has PT-780 and HTS-10568 on it. These same numbers are on BOTH builds, stand-up and laydown, so if anyone wants to get a duplicate made, make sure you tell them which way you want it built, because the scheduler's name seems to be Murphy!

A Marshall 100W JMP OT should do too, in a pinch, although they weigh less and more importantly the Zaa is a tad low for 6L6GCs. (But better for 6550s).

The OT is a big honkin' 100W Edcor, almost 10lbs. It's a special they did for Bob Houlton of RJ Guitars, model no. is EMO-734. Zaa is 2100 ohms, 4/8/16 sec. Bob may have some in stock, if not he can get it for you. This OT is MUCH bigger than a standard BF Twin OT. Edcor's 100W rating would be
-1dB from 20 to 20kHz, so in guitar amp terms it's good for 150W.

Pic of the upper chassis attached.

My 12BZ7 has 350V on the plate and cathode is at -51V. It has not yet been cranked because I don't want to destroy four '77 Celestion blackbacks. No signs of stress yet.

IIRC HAD used the screen node to supply the 12BH7 driver B+ in his 150W 6550 SSS, which had around 500V on the screens, as well as on the 6L6GC 100W, so I don't think he would have done that if there was any serious risk of failure. Driver current draw was likely very low most of the time, at least until pushed into AB2 and heavy grid current. Even then, larger gridstoppers can minimize grid current draw. I don't recall what HAD used on the 150W, but SSS 001 has 3K3 power tube gridstoppers..
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Last edited by David Root on Fri Nov 22, 2013 9:34 pm, edited 1 time in total.
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mhartman
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Re: My SSS 001 As Built, Corrected Schematics

Post by mhartman »

Thanks David. That looks awesome! I bet that it really shakes the walls when you crank it.
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