Seymore Duncan Twin Tube Classic pedal

[xvsop]

My TT Classic also started to crackle after a year or so. Called SD and they recommended to change the tubes. Actually I changed them to 6111's and for my use (bluesish) I like it better now (generally lower gain) Now it can go from a very warm clean to a pretty compressed tube-distortion. Does anyone of you guys have a suggestion of how to voice the thing more "fenderish"? It sounds quite "marshall" now, a bit dark...

Oivind

[Guitarist]

I wonder if the heater voltages are too high in the SD pedals. For their all rather cool designs in the past, sometimes they get voltage details wrong.
eg. 9 volts bias on cathode-bias el84s.

[skewik]

My TT Classic also started to crackle after a year or so. Called SD and they recommended to change the tubes. Actually I changed them to 6111's and for my use (bluesish) I like it better now (generally lower gain) Now it can go from a very warm clean to a pretty compressed tube-distortion. Does anyone of you guys have a suggestion of how to voice the thing more "fenderish"? It sounds quite "marshall" now, a bit dark...

Oivind

i am also looking to brighten the sound a bit, a bit more treble/bite perhaps.
any ideas if decreasing the 220 pfcap at input would help or perhaps changing the 4.7 uf bypass caps to 3.3 uf or even 2.2 uf would brighten the tone.

[George Jetson]

Anyone know what the "tonehunter" is doing to modify this pedal?

Tonehunter - Guitar Tone Customizing & Repair

Seymour Duncan Twin Tube - Mod 89,- €
More dynamics, better attack, finer gain, more tube tone!

[lowell]

I have one too, I LOVE it. it has gotten noisy with time as well. Most likely culprit in tube circuits? tubes. change 'em.

[dobrota]

Not to hijack, but i noticed the pedal has a 2.2M ground reference at the input where most amps have a 1M. is there a reason for this? I realize this is a tube pedal, but still. Why the 2.2M?

Why not ? 1M is typical and recomended for electric guitar, more is maybe a little better and 2.2M is just maximum for 12AX7 self bias mode.

[J M Fahey]

I hope it isn't the tubes, they should be lasting.

I neither believe in that.
For God's sake!! they are NOS Raytheon tubes, made for military equipment. Did you see the impact, vibration and G tests and ratings?
No civilian tube needs to specify that.
Yea, I know, Korean War vintage, probably.
What I *do* suspect is that those original connecting wires got somewhat
corroded in storage and they are not getting *really* soldered, but solder simply cools around them in the solder pad, and sort of crimps (poorly) the wire.
In a real soldered joint, there is no discontinuity , on one side you have solder (tin/lead), on the other side a different metal (copper, silver, gold, iron, whatever) and between them an alloy is formed, even if microns thick.
Those pins come "factory tinned" ...... 50 years ago.
Today I can't solder 1976 vintage MPSA10 transistors or 1986 tinned iron contacts jacks.
Tin plating doesn't hold well; yet vintage nickel plated jacks *can* be soldered without much trouble.
I think replacing tubes does simply "refresh" that poor connection .... which won't last long.
I would "polish" those tube wires with some steel wool or for the real daring, 600 grit wet/dry paper before soldering, and solder them at once.

[tjhamman]

twin tube pop

I too have a seymour duncan twin tube
it sounds great on the front end of my fender bandmaster
when i bought it new, it always bothered me that engaging the high gain channel resulted in a large pop
i opened it up and found one of the tubes had a lead that was connected
but had never been soldered, after soldering no more problem.

[DrKewel]

Hey Robert,

I am playing this with a Fender American Strat. On the Lead setting my Twin Tube buzzes to a very objectionable level when volume and gain are turned up past 5 which is unacceptably loud. I am asking Seymour Duncan for another power supply, but is there another possibility for this problem? Seems to be OK on Bypass and Rhythm settings.
Thanks in advance for your time,
Chris

[Patu]

My Twin Tube Classic started to do tricks. Both vol pots — on the Rhythm channel and on the Lead Channel — stopped working. The let the sound through foggy even when rolled to zero.

When I tweak the Rhythm vol pot to zero with a bit force, it lets all the noice thru. And when I knock the Lead vol pot's knob, it lets all the noice thru, too.

Obviously I have to change the pots (?). I opened the box and checked them and I surprised: they are not standard looking pots with three connectors but six!

I have read the schematics but did not figure out, what is the model and type of the mystery pots. Does anyone know it?

[J M Fahey]

Post the schematic and a couple pictures; also look at them with glasses (if necessary) and under a good light and post everything is written on them, even if it does not make sense.
"God helps those who help themselves" .... or something like that.

[lowell]

I'm very sad. My entire Pedalboard was stolen outta my car trunk... and my TTC was in there. I will surely be buying another one at some point. I never did fix the noise issue though. Soldering the tube pins did not help and the replacement tubes I bought ended up having short pins for sockets. Never did find where to get replacements... but didn't contact SD either.

[Patu]

Post the schematic and a couple pictures; also look at them with glasses (if necessary) and under a good light and post everything is written on them, even if it does not make sense.
"God helps those who help themselves" .... or something like that.

...and the repairman does the rest!

Next person asking the pots is my repairman — if he does not figure them out.

Thanks.

[Steve A.]

Thanks for posting the schematic here! I bought one of these several years ago at one of GC's "list events" with it going for about half of list price. When I tried it out in the store I thought that it was a little too aggressive for me but figured what the heck I will just change out the 12AX7's when I got it home. Only to discover that the tubes were subminiature suckers soldered in. Arghh!

When the TT Blue came out I saw that different tubes were used so I special ordered some from a tube shop in the UK and finally got around to putting them in (after dreading it for quite some time). It was easy as pi the way that SD had the leads splayed out. I liked that the gain was lower but was hoping to run across a schematic so that I might fine tune the circuit a little bit.

So thanks for posting it!

Steve Ahola

[NFXP]

I too would like to see a schematic for the twin tube blue, i wonder if they just changed the tubes or if the circuit has any differences.

Ive been useing an overdrive pedal to push my twin tube into over drive, i find with a the contour control on my marshall pedal i can dial in a better sound. Any issues to on tube life or circuit problems by not using the gain control of the pedal?