Cuduno Mig-60
- Thread starter CJ
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pucho812
Well-known member
In Soviet Russia amp distort you
schemo,
note stacked pwr xfmr secondaries so as to tap off lower voltage for screens thus avoiding tube meltdown since plates at 639 v, a first for this also:
note stacked pwr xfmr secondaries so as to tap off lower voltage for screens thus avoiding tube meltdown since plates at 639 v, a first for this also:
capacitorless
Well-known member
Cool!
I had one of the 50s, which was modded by Danny Russell and sounded great. Brrrr!
I had one of the 50s, which was modded by Danny Russell and sounded great. Brrrr!
Cool, I have not seen those russian tag strips for a while.
Does the clear russian goop stay non-conductive over time?
Does the clear russian goop stay non-conductive over time?
So far so good,
This guy had a blown B+ fuse, tubes mismatched and biased hot so one tube got away.
This guy had a blown B+ fuse, tubes mismatched and biased hot so one tube got away.
Vertical boards are a pain in the Fender DeVille series as they are inline with the sound waves generated by the speaker which results in self destruction.
AnalogPackrat
Well-known member
This is the kind of amp that really makes you appreciate what Leo did.
Jesus AP ,
Do you feel the need to inject your political bias into every thread you take part in ?
Im familiar with the modern Deluxe/Deville ,
I found mostly damaged sockets because of players trying to change out preamp tubes during a gig and either creating a dry joint where the socket pins meet the board or mangling up the point where the tube pins make contact .
As I said Ive come across a lot of this era fender amps and there very reliable apart from problems with the preamp tube sockets ,caused ,as far as I can see , by user error .
If you know what your looking for its an easy fix , thats good for the amp guy .
Do you feel the need to inject your political bias into every thread you take part in ?
Im familiar with the modern Deluxe/Deville ,
I found mostly damaged sockets because of players trying to change out preamp tubes during a gig and either creating a dry joint where the socket pins meet the board or mangling up the point where the tube pins make contact .
As I said Ive come across a lot of this era fender amps and there very reliable apart from problems with the preamp tube sockets ,caused ,as far as I can see , by user error .
If you know what your looking for its an easy fix , thats good for the amp guy .
AnalogPackrat
Well-known member
Eh? What does Leo Fender's amp design style (making service and repair easy) have to do with politics? For the record I also find American Ampeg amps of the 60s-70s a right PITA to work on. Nothing political was intended.
Not a Leo Fender design. He was gone by then.
PCB mounted tube sockets are not a good idea.
the speaker cabinets from the deville series suffer from extreme resonance at frequencies which just happen to be the same as the resonant frequency of the circuit board. so you fix the zeners, you fix the power resistors, you fix a few more things and the amp comes back, so you fix the tube sockets, then you fix the switches and the amp comes back, wash, rinse, repeat. so those amps are on the no fix list just like the marshall chip amps,
later on fender used more hold down screws on the board which kept the board from flopping around but unfortunately this improved the coupling to the chassis which also vibrates at the speaker resonance and so the chassis vibration ends up ripping the board apart.
this is why you see the foam tape on the chassis which does little good.
i used to just loosen the speaker hardware to lower the vibration but this was a bad way to fix a design problem.
not unlike the problems we had with the ultrasonic bonder, welding plastic cases around pc boards, if the board was coupled too well to the case, the parts would get ripped off the board in a matter of a few seconds. the solution was to have the board float on a foam washer during welding. even then, if a part was in the wrong location, it would break loose. solution here was to go to 1/8 watt resistors which had less mass and therefore did not rip itself off the board due to it's own inertia,
later on fender used more hold down screws on the board which kept the board from flopping around but unfortunately this improved the coupling to the chassis which also vibrates at the speaker resonance and so the chassis vibration ends up ripping the board apart.
this is why you see the foam tape on the chassis which does little good.
i used to just loosen the speaker hardware to lower the vibration but this was a bad way to fix a design problem.
not unlike the problems we had with the ultrasonic bonder, welding plastic cases around pc boards, if the board was coupled too well to the case, the parts would get ripped off the board in a matter of a few seconds. the solution was to have the board float on a foam washer during welding. even then, if a part was in the wrong location, it would break loose. solution here was to go to 1/8 watt resistors which had less mass and therefore did not rip itself off the board due to it's own inertia,
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It was a simple question AP , only required a yes or no answer ,
as usual you go off on a big roundabout loop trying to pick holes in anything people say and avoid the actual question .
Im well aware Leo left Fender sometime in the late 60's ,
Again I dont need to you tell me hardwired tube sockets are better , but your probably talking 4 times the price of a Custom Shop amp to get that .
Ive repaired many other tube amps with PCB mounted tubes on large single horizontal boards , aside from difficulty working on them , larger boards can be prone to lower frequency modes of vibration as well a scorching from power tubes because of poor air flow .
So Deluxes and Devilles are crossed off your repair list CJ ?
as usual you go off on a big roundabout loop trying to pick holes in anything people say and avoid the actual question .
Im well aware Leo left Fender sometime in the late 60's ,
Again I dont need to you tell me hardwired tube sockets are better , but your probably talking 4 times the price of a Custom Shop amp to get that .
Ive repaired many other tube amps with PCB mounted tubes on large single horizontal boards , aside from difficulty working on them , larger boards can be prone to lower frequency modes of vibration as well a scorching from power tubes because of poor air flow .
So Deluxes and Devilles are crossed off your repair list CJ ?
AnalogPackrat
Well-known member
No. I made no political comment here. Chill. The Siberian beast looks interesting, but more difficult to service than old Fenders due to the combo of PTP and vertical PCBs. I know CJ likes working on old Leo stuff because it was designed to be repairable.
I'll continue to comment when and where I please, thank you.
How does the amp sound, CJ?
