Twisted Snowflake

[martin manning]

One of the SSS has 470k to ground from each of the four output tube grids, so 235 per side. The potential problem is that the bipolar supply's negative voltage comes on with main power (like conventional bias), and until the driver tubes start conducting there is ~170V Vh-k. Some 12AX7's are only related to 100V. With the SSS's HT derived negative voltage it would be worse.

[bepone]

in tone stack 100nF bass cap connection is taken after 10nF middle cap?

[dorrisant]

bepone- good eye, I will correct that.

Martin - i remember that with the JM Sig, thanks for the explanation. I will add those. Should they be connected at the driver tube cathodes, or the power tube grids?

[martin manning]

... i remember that with the JM Sig, thanks for the explanation. I will add those. Should they be connected at the driver tube cathodes, or the power tube grids?

The SSS had them at the power tube grids, going to the cathode ground. I don't think it would make any difference, though.

[dorrisant]

Only the 3k3 per side difference. I didn't think it made much of a difference. It will give me two ways to proceed next time I open it up. Vacation for a week for now. Another fantastic player has it and will make some clips.
.

[dorrisant]

I edited my schematic on page 1 to reflect the errors pointed out above.

[dorrisant]

Oh yeah... another great local player. I loaned it to him while on vacation. Now he wants to buy one.

https://youtu.be/3PKPct7MyRA

Edit 6/20: Lindsey commissioned one of these, parts ordered. He said "I hate you, now I must have one."

[dorrisant]

Installed 270k resistors from cathode to ground of the cathode driver to avoid excessive Vh-k voltage at startup. Edited the schematic on page 1 as well.

IMG_20220623_153857835_HDR.jpg

[Guy77]

Hi Dorrisant, looks great! Did you notice any change in sound after installing those 270K resistors on pins 3 and 8?

Guy

[dorrisant]

No change at all. I did cull out a precisely matched set of 270ks in the hope that I didn't disturb the PI balance. Still sings very strong. Didn't have to adjust anything.

[Synchu]

Sounds great, looks great and it’s certainly built great.
What more can you ask for? ( and I have few spare transformer sets and chassis )

Niki

[dorrisant]

Sounds great, looks great and it’s certainly built great.
What more can you ask for? ( and I have few spare transformer sets and chassis )

Niki

Maybe a board set???

I have to make one set already... Why not two or three?

I just ordered a custom aluminum chassis from Seaside... Waiting on Dave at Mercury to finalize a quote for the TX set.

[Synchu]

I wish that was easy, but with shipping and customs, the cost will be prohibitive (plus that lately customs are taking it even easier than before).
I have a Tele body stuck for 6-7 weeks with them - with no explanation whatsoever - it is ridiculous. The most irritating part is that I ordered it via etsy from Ukraine - literally a few days before the war started, then the guys from the shop had to obviously get into fight and despite I told the owner - Victor, take care of yourself and family, stay alive, screw the money - use it however you like - he managed to make it and ship it a month or two later - then it took few weeks to get here and then for 6 weeks it is stuck with the posts and customs. How the guys managed over there, and the customs and posts here not - is beyond comprehension to me.
Rant and divert over, but in short - customs here suck big time lately :/

I have few other projects going over (an EF86 based pedal boost/drive among others ), but I will get to this at some point - can't resist cathode followers - since I did the SSS, I am a big fanboy And the sounds you posted prove why.

Niki

[dorrisant]

No worries Nikki, sorry you are dealing with that frustration. I would be livid.

I too have been working on some PCBs for tube based pedals and have recently rebuilt a Mesa V Twin into a Rocket based circuit for a customer. I am using my own version of the 555 SMPS to get the B+. The sickness continues.

[dorrisant]

After another build I have corrected the schematic on the first page. Also, here is a layout. Check for errors.

Last edit: 10-5-22