Fender Blues DeLuxe

[CJ]

nice sounding amp, two  6L6,  and a  12 inch  spk,  vol pot scratchy, plus other noises,

 

[CJ]

we hard wired an Alpha larger diameter pot in there, the Fender frame pots leave much to be desired, vol pot is most used, so why not put a better one in there,

also hard wired some Switchcraft 12B jacks instead of the old pc mount plastic stuff, and we bypassed the pwr amp in jack,

360 ohm 5 watt zener resistors are cooking the board, good thing we changed them to 390 7 watt, as they got so hot that the solder was loosened up, that was probably the other noise, vibration while playing cause the joint to freak out the mix,

we elevated the parts so the leads act as small heat sink and tried something new, a coil of magnet wire wrapped around each resistor and one end soldered to lead , between the increased R value and the heat sinking, we run cooler,  (blue arrow)

 

[CJ]

we popped the lid on the opt and used PRR method to bootleg turns without a tear down,

8 turns, inject 122 v, 8 T reads 0.437, 8 ohm wind reads 4.821,

4.821 / .437 = 11 exactly. nice to have a round number, means method is working,

11 x 8 = 88 turns for the 8 ohm wind,

4 ohm wind : 3.552 / .436 = 8.149, not a round number, what gives?

leakage ind. from the unused turns for the 8 ohm tap,

so we have 8 x 8 = 64 turns for the 4 ohm wind,

multiply these by the voltage ratio of pri to sec and get 2,172 turns full primary,

 

[CJ]

here iare the pwr amp voltages,

 

[abbey road d enfer]

we hard wired an Alpha larger diameter pot in there, the Fender frame pots leave much to be desired, vol pot is most used, so why not put a better one in there,

also hard wired some Switchcraft 12B jacks instead of the old pc mount plastic stuff, and we bypassed the pwr amp in jack,

360 ohm 5 watt zener resistors are cooking the board, good thing we changed them to 390 7 watt, as they got so hot that the solder was loosened up, that was probably the other noise, vibration while playing cause the joint to freak out the mix,

You pretty much summed up the recurrent problems of this otherwise rather good series of amps, although there are rants about each new version being less good than the previous.

 

[CJ]

it is a lot like a pro Reverb with overdrive and a solid state reverb circuit, it has a good cabinet and a good speaker, at least in this era

this output transformer from Shumacher is probably the same design they used in the pro reverb>

why do they shim the coil? finally figured that out, the hot spot on most transformers is the first layers, near the core, the shim lets a little air flow through there,

 

[CJ]

overdrive output to 8 ohm resistive load>

 

[CJ]

sq wave input to amp produces this at output>

 

[CJ]

output transformer shim>

 

[abbey road d enfer]

the shim lets a little air flow through there,

Does it ? Seems to me like the end bells block any airflow...

 

[CJ]

preamp voltages for normal and lead

 

[CJ]

preamp voltages,

colors kept self-erasing and turning to black while saving file, tried it again like 4 times, figured out it was the background excrypted with some sort of bit manipulation,

 

[Tubetec]

Ive had my fair share of Deluxe's and Deville's ,superb amps really ,like you rightly pointed out though ,the signal jacks are garbage .Later versions seem to have tougher jacks ,not the ones with the metal insert and a tiny nut with about three threads that fall to pieces.
Another thing I routinely check is the solder joints to the tube sockets, Ive had several with this particular fault .Most likely caused by someone fumbling round trying to switch out a pre amp tube and damaging it ,but vibrations seem to help this fault occur too . My buddies dads Deluxe holds my record for a pair of 5881 ,five or six years of several nights a week of gigs ,and that set still had plenty of life left in them when they got swapped out . One other odd ball fault that Ive seen on a deville was an issue with the switched speaker jacks where a dead short across the output terminals happened ,very low distorted output ,but everything measured spot on inside ,bit of a head scratcher but I sorted it in the end.

 

[Gus]

CJ

If you want to try a cap experiment change the first two caps in the PS (plate and screen)
If you have a cap checker measure all the parameters you can of the caps and note what happens

 

[abbey road d enfer]

If you want to try a cap experiment change the first two caps in the PS (plate and screen)
If you have a cap checker measure all the parameters you can of the caps and note what happens

What do you mean "change"? Change the value or brand, or something else? What can be expected by "changing" caps?