Your Source for DIY Pedal PCBs and NostalgiTone! › GuitarPCB Forum › Show Off Your Build › Sunn Model T Preamp
- This topic has 6 replies, 3 voices, and was last updated 6 years, 5 months ago by
Anonymous.
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September 4, 2019 at 2:43 am #6796
Anonymous
InactiveWell, I finally finished the Sunn Model T Preamp pedal last week.

The only problem I’m facing at the moment is some volume issues. I run the OD/DS-section before the Sunn and need to turn the Sunn’s Volume to max in order to achieve unity volume…can’t be right, right? 🙂
September 4, 2019 at 12:00 pm #6799
BarryKeymasterWhat exactly are you running before the Sunn, more detail please.
What happens you just use the Sunn by itself with only two good cables straight into your amp.
The Sunn itself by circuit design has plenty of available Volume.
Where did you obtain the transistors?
September 5, 2019 at 9:07 am #6804Anonymous
InactiveHi Barry,
I switched my home-amp to 0.5W and get unity volume at around Sunn Master volume at 3:00.
Tried running the Sunn alone and get the same results as if I placed my other stuff before it…the other pedals before the Sunn are/were Bogner Burnley, Xotic EP, JHS Morning Glory V4, Analogman Prince of Tone and Maxon OD808.
Got the transistors as part of the whole bundle from Musikding.
September 5, 2019 at 1:32 pm #6807Anonymous
GuestYou are now reporting that you achieve unity volume level at about 3:00 o’clock on the Volume pot. Setting both Gain controls at max should produce unity level near 2:00 o’clock. So, you are not that far off from the expected results. I suggest you try adjusting all three trimmers to increase the output of the transistors. As long as you can achieve unity level, you are achieving the desired results. The SUNN T is primarily designed as a tonal modification device. It was not intended to be simply a volume boost. I think you are close to achieving the desired tones.
September 5, 2019 at 2:06 pm #6808Anonymous
InactiveYeah, I think I was too fast in my original when I stated that I achieve unity volume at max only.
To what degree can I adjust the trims? I (as far as I can remember) adjusted them to the values in the description. Just asking cause I don’t want to destroy anything…
btw, thanks for your fast responses!!!
September 5, 2019 at 3:44 pm #6809Anonymous
GuestI suggest you adjust each trimmer one at a time. Listen and measure the voltage. You can probably raise the voltage up to 6 or 7 volts without any damage. You should hear the results and select a tone that you like.
September 6, 2019 at 2:59 am #6810Anonymous
InactiveThanks, wilkie! Will try that on monday!
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