Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Papa Jim on February 11, 2019, 02:29:38 pm

Title: New 5F2 Build with 2 deviations. Would like a cleaner sound.
Post by: Papa Jim on February 11, 2019, 02:29:38 pm: Okay so I built the 5F2. All I had was a 6V6S so chose to try it for output tube. Also used diode full wave bridge PS. It sounds great but has more overdrive and I would like to be cleaner. Can that be achieved by resistor/bias changes? Or will the correct tube help. Following is the voltage readings I took at the places shown on the schematic at the tube pins.
SCHEMATIC https://el34world.com/charts/Schematics/files/Fender/Fender_princeton_5f2_schem.pdf

12AX7
Pin-1 183.7
Pin-6 186
Pin-3 1.319
Pin-8 1.368

6V6S
Pin-8 19.82
Title: Re: New 5F2 Build with 2 deviations. Would like a cleaner sound.
Post by: EL34 on February 11, 2019, 02:34:34 pm: Moved, posted in wrong board
Title: Re: New 5F2 Build with 2 deviations. Would like a cleaner sound.
Post by: sith on February 11, 2019, 05:05:38 pm: When it start to break? if it's at about 11 o'clock it's pretty normal… maybe try to swap preamp tube to 12AT7 or AY (what are the other voltages at 6V6?)
Title: Re: New 5F2 Build with 2 deviations. Would like a cleaner sound.
Post by: sluckey on February 11, 2019, 05:15:40 pm: What is the voltage on the three filter caps?
Title: Re: New 5F2 Build with 2 deviations. Would like a cleaner sound.
Post by: Papa Jim on February 11, 2019, 08:40:50 pm: The B+ Voltages are 326 before the choke, 321 after the choke for the 6v6, and 281 for the 12ax7 preamp tubes.
Title: Re: New 5F2 Build with 2 deviations. Would like a cleaner sound.
Post by: sith on February 12, 2019, 03:20:28 pm: wait you said Hammond 125C, not 125SEC, someone correct me if I'm wrong but thats PP tranny not SE, it might work, but afaik not best match, one of possible side effects might be more pronounced distortion due to core saturation… :dontknow:
Title: Re: New 5F2 Build with 2 deviations. Would like a cleaner sound.
Post by: Papa Jim on February 12, 2019, 06:07:56 pm: Yes thanks for pointing that out about the wrong tranny. Wow, Funny I was just reading after stumbling upon a post about how that would not be best thing to do, unknowingly doing that exact thing. Hard telling how long I may have went not realizing it even though I read the article. Gonna definitely purchase the correct SE Tranny. I feel kinda stupid about this but bet I won't do it again. Lol

Guess I better check the classified section here for something suitable.
Title: Re: New 5F2 Build with 2 deviations. Would like a cleaner sound.
Post by: Slimtim on February 12, 2019, 08:38:45 pm: i have something that might work.you can have it for the shipping price.it's from a old silvertone s.e. organ pushing a 6aq5.it's been in the closet for years waiting for me build it up but i dont need or want anymore amps.an 18 and 50 is enough for me.sluckey or silvergun or someone here built one just like it and put a thread here for their build with p?ics.he used all 6 pin tubes.4 6au6 and a 6aq5.now what was the name of that thread?

silverstoned organ amp hack.is the name of the thread.it was dummyload who built it.his first post in that thread has a photos and layout link and below the link is a schem.check and see if it's close to what you need if you're interested.
Title: Re: New 5F2 Build with 2 deviations. Would like a cleaner sound.
Post by: sith on February 13, 2019, 01:31:25 pm: well, not all bad things... with that OPT you can bulid something like BF era Princeton amp, think it would suit your needs even better… u only need one more ax7 (even more 12AT7 or AY7, for more cleaner sound) one 6V6 and handfull of resistors and caps…
from what I've read over the internet they are the tone machines (sadly so far I built only SE amps, so no 1st hand expirience with them) :wink:
Title: Re: New 5F2 Build with 2 deviations. Would like a cleaner sound.
Post by: Papa Jim on March 15, 2019, 06:31:55 am: Thanks for the suggestion Sith. I am pretty sure I am gonna convert my amp like you mentioned.

Thanks to you also Slimtim. I have a couple of fender ot's that may work now.