Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ratlordfx on May 24, 2021, 11:20:22 pm

Title: Danelectro Centurian Series D Model 72 - No Schematics, Noisy Output
Post by: ratlordfx on May 24, 2021, 11:20:22 pm
Ive had this amp sitting around for a few years and the last time I fired it up, I was just getting noise out of the speaker.  I chalked this up to bad capacitors and went about changing all the wax and electrolytics, but i could still never get it to work right.  without a schematic, at this point I am a bit lost due to its funky design.  it looks like a better design than the layouts i am finding, but the closest thing so far has been the model 89. 

could anybody shed some light on this?  i think i once read that this was a clone of the Brownface era vibrochamp..  no reverb tank.

any help is much appreciated

regards,
RL
Title: Re: Danelectro Centurian Series D Model 72 - No Schematics, Noisy Output
Post by: ratlordfx on May 24, 2021, 11:26:46 pm
heres some pics
Title: Re: Danelectro Centurian Series D Model 72 - No Schematics, Noisy Output
Post by: PRR on May 25, 2021, 04:10:49 pm
> i think i once read that this was a clone of the Brownface era vibrochamp..

Which VibroChamp had two 6V6es?

But anyway, it's just an amp. What is this "noise"? Hiss? Hum? Cicadas? Cackles? Montenegrin disco music? Did you find any mouse-pee? voltages? in there?
Title: Re: Danelectro Centurian Series D Model 72 - No Schematics, Noisy Output
Post by: ratlordfx on May 25, 2021, 04:51:45 pm
Quote from: PRR on May 25, 2021, 04:10:49 pm
> i think i once read that this was a clone of the Brownface era vibrochamp..

Which VibroChamp had two 6V6es?

But anyway, it's just an amp. What is this "noise"? Hiss? Hum? Cicadas? Cackles? Montenegrin disco music? Did you find any mouse-pee? voltages? in there?

Yeah I just read that, never really took it into consideration.

I haven't powered it on in a while,  but last time I fired it up with a speaker attached, there were heavy oscillating thumps and some whistling (only when adjusting the tone control).  After recapping with no luck and no sign of schematics, I put it in the closet.

Title: Re: Danelectro Centurian Series D Model 72 - No Schematics, Noisy Output
Post by: acheld on May 25, 2021, 04:52:54 pm
Some hi-rez gunshots would be helpful.     EDIT:  gut shot.   Don't want to hurt the amp in any way!
Title: Re: Danelectro Centurian Series D Model 72 - No Schematics, Noisy Output
Post by: tubenit on May 25, 2021, 07:46:16 pm
Look at the Dano Centurian 275 schematic.  AND the Silvertone 1482 schematic.


Danelectro_centurian_275.pdf (el34world.com) (https://el34world.com/charts/Schematics/files/Danelectro/Danelectro_centurian_275.pdf)


The Dano Centurian  275  I had is the ONLY manufactured amp I regret selling.



I'll bet a nickel your amp is pretty close to one of those.  Dano didn't change a whole lot from one to the other of those push/pull 6V6 amps.


with respect, Tubenit
Title: Re: Danelectro Centurian Series D Model 72 - No Schematics, Noisy Output
Post by: PRR on May 25, 2021, 09:54:09 pm
It is a CHEAP amp. And now OLD. I would just *carefully* replace all the electrolytic capacitors. And meter all the "pair" resistors, cuz my first motoboat was a pair of 47k CC resistors drifted to 52k on one side and 98k on the other side. (Probably combined with decayed caps, but I didn't get that far.)

And with 2 6V6 it kinda has to be a lot like those amps Tubenit linked. Or if not, comparison will show what is different.
Title: Re: Danelectro Centurian Series D Model 72 - No Schematics, Noisy Output
Post by: ratlordfx on May 27, 2021, 01:07:29 pm
Quote from: tubenit on May 25, 2021, 07:46:16 pm
Look at the Dano Centurian 275 schematic.  AND the Silvertone 1482 schematic.


Danelectro_centurian_275.pdf (el34world.com) (https://el34world.com/charts/Schematics/files/Danelectro/Danelectro_centurian_275.pdf)


The Dano Centurian  275  I had is the ONLY manufactured amp I regret selling.



I'll bet a nickel your amp is pretty close to one of those.  Dano didn't change a whole lot from one to the other of those push/pull 6V6 amps.


with respect, Tubenit

I've been digging around and found a weird "Epiphone Dano century" schematic that is almost identical.  Everything is the same except there is no bass control.
All the caps have been changed and I did have a few resistors that were off a bit, but still motorboating after I changed them. 

I noticed that there are no coupling caps from the 68k resistors to the grid of V1... It's the same way in the centurion too

I'll keep you guys updated, and get back with some gutshots ;)

Title: Re: Danelectro Centurian Series D Model 72 - No Schematics, Noisy Output
Post by: sluckey on May 27, 2021, 01:21:04 pm
Quote from: ratlordfx on May 27, 2021, 01:07:29 pm
and get back with some gutshots ;)
Hope they're bigger than that postage stamp schematic. Wonder how anyone could even draw that small.    :icon_biggrin:

     https://el34world.com/charts/Schematics/files/Epiphone/Epiphone_dano_century30_1961.pdf
Title: Re: Danelectro Centurian Series D Model 72 - No Schematics, Noisy Output
Post by: ratlordfx on May 27, 2021, 01:25:29 pm
Quote from: sluckey on May 27, 2021, 01:21:04 pm
Quote from: ratlordfx on May 27, 2021, 01:07:29 pm
and get back with some gutshots ;)
Hope they're bigger than that postage stamp schematic. Wonder how anyone could even draw that small.    :icon_biggrin:

     https://el34world.com/charts/Schematics/files/Epiphone/Epiphone_dano_century30_1961.pdf

Lol my bad, I had to screenshot it.  Here's the pdf
Title: Re: Danelectro Centurian Series D Model 72 - No Schematics, Noisy Output
Post by: PRR on May 27, 2021, 02:04:20 pm
Quote from: sluckey on May 27, 2021, 01:21:04 pm
....Wonder how anyone could even draw that small.  ...

Apparently with a very small pencil and a non-bending colonoscopy scope.
video (https://youtu.be/WstmqAuqRvA?t=123)

And a chit-likkin' grin.