Search found 182 matches

by sixstringer
Mon Dec 18, 2023 10:14 pm
Forum: Garage Talk
Topic: Tone control for acoustasonic Tele
Replies: 1
Views: 986

Tone control for acoustasonic Tele

I'd like to add a tone control to a Fender Acoustasonic Tele. Stock it has a volume and "blend" control but no tone control. Adding a passive tone control (treble roll-off) does not seem like a daunting project. What do you think?
Thanks
by sixstringer
Fri Feb 10, 2023 1:40 am
Forum: Fender Discussion
Topic: AA764 Champ Farts Out, help!
Replies: 4
Views: 1317

Re: AA764 Champ Farts Out, help!

Turns out it was the Tubes after all. Replaced the old tubes with new and now it should like a Champ. And the TSB switch adds a nice crunch.
Thanks, everyone for your help and advice. I'm going to try the cap value adjustments too.
by sixstringer
Wed Feb 08, 2023 10:33 pm
Forum: Fender Discussion
Topic: AA764 Champ Farts Out, help!
Replies: 4
Views: 1317

AA764 Champ Farts Out, help!

1966 Fender black-face Champ (non-vibrato). All new electrolytic caps, new 8" MOD speaker. The only mod is a tone stack bypass switch. The circuit is stock with the TSB turned off. The amp farts out significantly at medium and above volume with/without the TBS engaged. Tubes are original by test goo...
by sixstringer
Fri Apr 17, 2020 7:55 pm
Forum: Technical Discussion
Topic: Rectifier help
Replies: 24
Views: 1798

Re: Rectifier help

With the 150r bias resistor, the plate dissipation is down to 9w, which seems very safe for a JJ 6v6 (14w max) in a class A application. Also, I changed the bypass cap on V1 to improve the highs and I like it better. The amp is working fine.
Thanks for all your help and advice.
by sixstringer
Tue Mar 31, 2020 12:56 am
Forum: Technical Discussion
Topic: Rectifier help
Replies: 24
Views: 1798

Re: Rectifier help

Power Tube (EL-84 ) voltages:
Plate (pin 7) 257vdc
Cathode (pin 3) 6.5vdc
Screen Grid (pin 9) 249vdc
Control Gri (pin 2) .137vdc

Voltage drop across the Cathode resistor: 6.5vdc
Cathode resistor value is 120 R

267 vdc (B+) from the rectifier
by sixstringer
Sat Mar 28, 2020 11:19 pm
Forum: Technical Discussion
Topic: Rectifier help
Replies: 24
Views: 1798

Re: Rectifier help

OK! with the rectifier circuit change per Martin's modded layout, the voltages are now within a couple of volts of those on the original schematic. Thanks for your help! Do you have any advice on how to get this circuit to be more "chimey" and no so mid-range heavy? I am hoping to get more that EL-8...
by sixstringer
Thu Mar 26, 2020 1:47 am
Forum: Technical Discussion
Topic: Rectifier help
Replies: 24
Views: 1798

Re: Rectifier help

Even if i have only one El-84 installed?
by sixstringer
Wed Mar 25, 2020 4:33 pm
Forum: Technical Discussion
Topic: Rectifier help
Replies: 24
Views: 1798

Re: Rectifier help

Martin, that's how I had it originally, which made more sense to me but I was only getting 245vdc B+ and the amp had no punch at all, after changing to it, the vdc went up over 100vdc and it sounds much better, but I'm thinking of adding a diode to lower the B+ a bit. I still like your circuit bette...
by sixstringer
Mon Mar 23, 2020 8:24 pm
Forum: Technical Discussion
Topic: Rectifier help
Replies: 24
Views: 1798

Re: Rectifier help

Here is the schematic
by sixstringer
Mon Mar 23, 2020 8:15 pm
Forum: Technical Discussion
Topic: Rectifier help
Replies: 24
Views: 1798

Re: Rectifier help

Posted in error
by sixstringer
Mon Mar 23, 2020 12:17 am
Forum: Technical Discussion
Topic: Rectifier help
Replies: 24
Views: 1798

Re: Rectifier help

this is how it's wired now. This is from Mat's 86 Special layout from a few years ago. I added an additional EL84 in series to make it dual single-ended.
by sixstringer
Sun Mar 22, 2020 10:25 pm
Forum: Technical Discussion
Topic: Rectifier help
Replies: 24
Views: 1798

Re: Rectifier help

Thanks, I don't understand why but moving the ground from the center tap of the transformer to the negative side of the rectifier fixed the issue. i now have 379 vdc out of the rectifier. I was mistaken about the diodes, they are N40007 rather than 40001. Ultimately, I'm trying to find out why this ...
by sixstringer
Sun Mar 22, 2020 8:19 pm
Forum: Technical Discussion
Topic: Rectifier help
Replies: 24
Views: 1798

Rectifier help

I have a Hammond 269EX going to two N4001 diodes to form a bridge rectifier. The center tap of the B+ is going to ground. I have 205vac per side into the diodes but only 245vdc coming out. I could change the rectifier to full bridge, adding two more diodes, lift the center tap ground from the transf...
by sixstringer
Mon Apr 10, 2017 6:41 pm
Forum: Fender Discussion
Topic: fender deluxe homemade too bright and clean
Replies: 9
Views: 1864

Re: fender deluxe homemade too bright and clean

If you have 170v or more on the plates of the pre-amp tubes you could try dropping the voltage off the power rail at “B” so you get closer to 100v on those plates, that will brown up the amp and give you earlier breakup. Also, you could try changing the rectifier tube to a NOS tube and see as much a...
by sixstringer
Thu Sep 15, 2016 5:13 pm
Forum: Technical Discussion
Topic: Gretsch 6150t Supro 16t amplifier build
Replies: 3
Views: 2010

Re: Gretsch 6150t Supro 16t amplifier build

Nice build, You could use a power resistor for impedance matching too. I use these for impedance matching when building attenuators. You could paint the inside of the apexjr clear pilot jewel and get that milky white glow similar to the valco amp. The white jewel from AES is close to the correct loo...