Yet Another SSS - Variation on a Theme

[jam-mill]

This is my take on the SSS based on various information learned here at the Amp Garage - thank-you to those that have shared information for the hobbyist.

Information gleaned from MHartman (his take on an SSS) and big thanks to Martin Manning for the revised step filters.

Purchased the chassis and head cabinet from Taylor (Amplified Nation) and the transformer set from Colossal (Dave).

So, after a year in the making the amp is finally complete and it has been worth the wait.

Note that this particular variation does not employ the cathode follower after the PI; however, based on comparisons with recordings found here and on YouTube, sacrifices nothing as a result.

The reverb section needs to be tweaked a bit for my taste and could just be an adjustment to the mixer resistor to tame it a bit. However, it does sound incredibly rich and even holds up while being driven by a high-gain distortion pedal (Dave Barber Direct Drive).

Some technical details:
The B+ value (no load) is 462VDC, but drops to 445VDC when the stand-by switch is thrown.

The output stage is biased for 70% of 25W per tube - about 39mA or so.

The reverb B+ is dropped down with a 56K resistor such that there is only about 310VDC on the plates (I won't be burning up the reverb driver as a result). Not sure why so many amps
dump 400+ volts on the plate of a 12AT7, significantly exceeding its rated voltage.

Am now intrigued by how the cathode follower after the PI would affect the tone and playability of this amp. So, as time, money, and, most importantly, my wife permits, I'd like to build another SSS variation with that configuration.

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[jam-mill]

One more picture.

IMG_1625.JPG

EDIT: Added layout.

SSS_Amp-AG.png

[Abe5150]

Looks good!

[xtian]

Bril, mate! Congratulations, and thanks for the details.

[norburybrook]

wonderful


so is this basically a JM Wonderland with step filters?


My Jm has a 500v Dc plate voltage ansd a different voltage divider fro more gain but with the cot control out of the loop and the NFB switches off ot sounds to me like a SSS


congrats on a great build.


M

[jam-mill]

Bril, mate! Congratulations, and thanks for the details.

Thank-You, Aaron.

[jam-mill]

wonderful


so is this basically a JM Wonderland with step filters?


My Jm has a 500v Dc plate voltage ansd a different voltage divider fro more gain but with the cot control out of the loop and the NFB switches off ot sounds to me like a SSS


congrats on a great build.


M

Marcus,

I suppose that, basically, it is similar to a JM Wonderland with the addition of step filters; however, there is more local feedback applied in various places in the 'SSS' variation.
Also, the global feedback is fixed as there is no presence control.

Wow - 500 VDC on the plates - seems to me that if operated with the master turned up significantly that the output tubes would be periodically driven to a red-plate condition.
What kind of tubes are you using? What is the bias current? What is the OT primary impedance?

Thank-you for the kind compliment.

-jack

[pompeiisneaks]

Wow, just wow! Looks amazing!

~Phil

[rootz]

Wow what a nice build! And those transformers, jeez that OT is colossal.

[norburybrook]

wonderful


so is this basically a JM Wonderland with step filters?


My Jm has a 500v Dc plate voltage ansd a different voltage divider fro more gain but with the cot control out of the loop and the NFB switches off ot sounds to me like a SSS


congrats on a great build.


M

Marcus,

I suppose that, basically, it is similar to a JM Wonderland with the addition of step filters; however, there is more local feedback applied in various places in the 'SSS' variation.
Also, the global feedback is fixed as there is no presence control.

Wow - 500 VDC on the plates - seems to me that if operated with the master turned up significantly that the output tubes would be periodically driven to a red-plate condition.
What kind of tubes are you using? What is the bias current? What is the OT primary impedance?

Thank-you for the kind compliment.

-jack

JAck,

the PT and OT are from an old early 80's Peavey Triumph . Dumble used these transformers so I grabbed this amp when I saw it. Got a nice set of black plate 6L6's too that are now in my tweedle dee.

I used a FWBR like the original Peavey schematic (I think the B+ was 511 vDC on the schematic ) but I had to use a voltage doubler to get enough -ve bias voltage as the peavey must have been on the edge.

I'm using JJ6L6's and the amp is generally played loud it's a lovely thing, really is I don't use it often enough as you need to use pedals for OD and I'm so used to the ODS amps or my Tweedle Dee that OD naturally.

I see you've called it the same as I did 'Steel String Special '

Marcus SSS.jpg

Great build and a lovely looking amp, you must be very happy with it.

There's a part of me would like to do a full on #004 SSS but finding a Chassis is the hard part here in the UK. That's probably the main thing stopping me.

enjoy your amp


M

[Synchu]

You can always get a Tube Town blank and punch it, as I did.
You need a SSS. It’s a great amp.
Niki

[jam-mill]

Wow, just wow! Looks amazing!

~Phil

Thank-You Phil, I appreciate the compliment very much.

BTW, thank-you for all the work you do in maintaining and contributing to this site.

-jack

[jam-mill]

wonderful


so is this basically a JM Wonderland with step filters?


My Jm has a 500v Dc plate voltage ansd a different voltage divider fro more gain but with the cot control out of the loop and the NFB switches off ot sounds to me like a SSS


congrats on a great build.


M

Marcus,

I suppose that, basically, it is similar to a JM Wonderland with the addition of step filters; however, there is more local feedback applied in various places in the 'SSS' variation.
Also, the global feedback is fixed as there is no presence control.

Wow - 500 VDC on the plates - seems to me that if operated with the master turned up significantly that the output tubes would be periodically driven to a red-plate condition.
What kind of tubes are you using? What is the bias current? What is the OT primary impedance?

Thank-you for the kind compliment.

-jack

JAck,

the PT and OT are from an old early 80's Peavey Triumph . Dumble used these transformers so I grabbed this amp when I saw it. Got a nice set of black plate 6L6's too that are now in my tweedle dee.

I used a FWBR like the original Peavey schematic (I think the B+ was 511 vDC on the schematic ) but I had to use a voltage doubler to get enough -ve bias voltage as the peavey must have been on the edge.

I'm using JJ6L6's and the amp is generally played loud it's a lovely thing, really is I don't use it often enough as you need to use pedals for OD and I'm so used to the ODS amps or my Tweedle Dee that OD naturally.

I see you've called it the same as I did 'Steel String Special '

Marcus SSS.jpg




Great build and a lovely looking amp, you must be very happy with it.

There's a part of me would like to do a full on #004 SSS but finding a Chassis is the hard part here in the UK. That's probably the main thing stopping me.

enjoy your amp


M

Marcus,

I'd for gotten that you had called your amp a 'Steel String Special' - so, now there are two of them in the world; one on each side of 'the pond'.

I am amazed at the head cabinets you have produced with minimal wood-working tools; will have to endeavor that aspect of an amp build sometime.

I appreciate your kind remarks and also the work that you contribute here regarding your builds. You have produced some nice amps.

-jack

[jam-mill]

Added layout to second post.