Recent Posts

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Tube Amp Building - Tweaks - Repairs / Re: After cap update there's a loss of attack/sensitivity

« Last post by pbman1953 on September 14, 2026, 11:17:26 am »

Thanks I'll start with the easy stuff first the pin 3

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Tube Amp Building - Tweaks - Repairs / Re: After cap update there's a loss of attack/sensitivity

« Last post by tubenit on September 14, 2026, 11:11:18 am »

An output transformer change can make a significant difference tonally.  Usually an improvement in my experience but not always. I upgraded a Dano Centurian 275 with a Deluxe Reverb OT .......... and after about an hr of playing, I put the original back in.


Of what you mentioned ............ I would guess the OT change and the cathode pin 3 resistor change would be the more dramatic differences.


with respect, Tubenit

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Tube Amp Building - Tweaks - Repairs / After cap update there's a loss of attack/sensitivity

« Last post by pbman1953 on September 14, 2026, 09:29:50 am »

Back to the  Fender Super Twin for a sec. Even though I'm done with these the amps they had more attack/sensitivity before changing anything. Cap changes were made because it was humming badly and the new caps solved that. The cap kit I bought were very close values to the schematic. With conversation in the forum here's the changes that were suggested:


1- V1A- pin 6-100k resistor to a 68k
2- V1B -pin 3 -1500 resistor to a 680 ohm
3- V4B pin 1 from a 220k resistor to a 180k




Other real changes- new OT's so I could have outputs for 4 & 8 ohm. The first amp has a Mercury Magnetics OT and the second one has Heyboer. If you feel the OT's are the reason for the difference , enough said, otherwise I'm wondering if the preapp should go back to stock values.


I have 2 versions of this amp so I'll send both schematics . One is an older version and one is a version in between a non-reverb and a reverb version. Both are non-reverb

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Tube Amp Building - Tweaks - Repairs / Re: Combining Stout TMB + Stout Reverb

« Last post by martinman on September 14, 2026, 06:20:02 am »

Thanks everyone.  I *knew* someone was as interested in this as I am! 

Any chance you can point me to a layout?  I can read schematics, but doing the translation to a board...  eh. gonna get it wrong for sure. 

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Tube Amp Building - Tweaks - Repairs / Re: First amp build

« Last post by AlNewman on September 13, 2026, 11:54:11 pm »

Those voltages don't make much sense.

If it's motorboating or squealing, you can try switching primary leads of the output transformer between the 2 plates of the output tubes...

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Tube Amp Building - Tweaks - Repairs / Re: THE HOWLER

« Last post by dogburn on September 13, 2026, 09:27:22 pm »

Wow - very professional, and they have their own distinct look (which is somewhat rare these days).

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Tube Amp Building - Tweaks - Repairs / Re: First amp build

« Last post by Mongrel714 on September 13, 2026, 07:41:00 pm »

On the pre amp:
Pin 1- +143vdc
     2- +0
     3- +6v
   4&5- 3.4vac
     6- +235vdc
     7- +0
     8- +13v
     9- +3.4vac
EL84
Pin 1- 0
     2- -15vdc
     3- 0
   4&5- 3.4vac
     6-0
     7- +370vdc
     8-0
    9- +365vdc
I didnt get the phase inverter numbers as it was Motorboating, pulled the PI tube and it stopped, so either pre amp or PI section?

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Other Topics / Re: Meme of the day

« Last post by shooter on September 13, 2026, 06:00:34 pm »

....

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Tube Amp Building - Tweaks - Repairs / Re: First amp build (5F1) would anyone mind double checking my turret board layout?

« Last post by Platefire on September 13, 2026, 02:58:28 pm »

Some of us hike up the value of those power rail filter caps to get rid of the original Fender F51 humm. Think I went to 22/10/8 and it still remains a little humm

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Tube Amp Building - Tweaks - Repairs / Re: THE HOWLER

« Last post by Platefire on September 13, 2026, 02:47:05 pm »

Wow! I Like!!!