time for more Joule Electra

WagnerRC

no red plates at all. The volume just became uncontrollable. I am betting one of the other tubes have an issue. Thanks

tonyb

Dang, I want to see more pics of that sucker. Just to be clear too....

WagnerRC

meanwhile back at the ranch. I am still waiting to get the tubes tested but I did solve a large piece of the puzzle.

This may be hard to follow. I was using the squeezebox routed through the dac of the 306 via xlr cables and I also had the rca cables from the 306 to the slp-05 too.

I mistakenly plugged the rca cable into the cinema plugs instead of the number 1 rca connections .... . DOH!

so when I had the hum/buzz and tied to turn the sound off on the slp-05 it automatically went into cinema mode when powered of as designed.

That created the squeezbox volume at max level..... there was no music playing at that time due to ca commercial break on the internet radio. But it increaded the hum which is when I had you yank the power to the vzn.

This really clears up what happen so the amp should be an easy fix once I get the tube tester from Snow.

I hope this is clear as mud to understand. It all makes sense to me now.

Double check your cabling dumbazz .......


Cheers

george daniel

Been there,done that,, good news indeed,,when are you gonna pop that puppy back in?

WagnerRC

I will be testing it today on a smaller scale until I can get the tube tester here.

WagnerRC

Hooked it up and still getting the buzz out of the left speaker. This is hooked up to a small set of era speakers to limit damage if something failed. As soon as the voltage reached the 60 volts the buzz was present. I will try swapping in 2 new ec66 tubes to the left channel to see if I can isolate the suspect tube, if that what it is. It has to be in my mind.

george daniel

Hmmmmm,, hopefully it is a bad tube,,, if not,, you think it might be a bad cap?

WagnerRC

Power tubes are fine, no change swapping them out. I believe this is the key to what might be going on.

Set the variac to 40. check the dc offset of both channels Right is 68.5 and the left (which is the problem channel) is 113.1

why would there is such a difference in DC offset ? hmmm

WagnerRC

I guess that I could swap the right tubes into the left tube location to see if the voltage change follows the tubes.

Those 4 tubes do run higher. left is 70 vs. right is 117 now

george daniel

If the problem is following the tubes when you swapped them,, I think you have a bad tube or tubes,,good luck and keep us posted

tonyb

Sorry to hear that Bob, perfect example though of why I gave up on tube amps, especially ones with boat loads of tubes. Pain in the butt trying to figure out which is bad, having to have so many on hand just in case. Gets aggravating.....you just have to weigh the sound advantages to the aggravation aspect and see where your at. Hopefully you get it sorted out soon, as I'd like to hear more about some comparisons.

WagnerRC

Gig Harbor Audio can test the 6c33 tubes for me. Dropping them off today.

george daniel

Attaboy

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WagnerRC

Good call Yep2 these sockets are surprising clean and well kept. That is why I don't think this amp has a heck of a lot of wear and tear. We shall see I guess.

Snow shipped the sencore tester today so I will have that next week to test the other tubes.

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WagnerRC

Just got a call..... we cant test russian tubes..... back to the drawing board

george daniel

Damn,, I have been following your thread,, still think you are right about a bad tube or more. Good luck

WagnerRC

I am going to try replacing the tubes in order in a new sequence. stay tuned.

edit, she is singing again. woo hoo

tonyb

Dang she's a beaut.....so you found the bad tube I take it ?

george daniel

Attaboy!

WagnerRC

Yes it was a bad power tube. Once I went by Jud's tube layout it was easy to figure out. It is even quieter now too. Super happy for sure. Bugle boys going in next week too.

WagnerRC

george daniel wrote: »

Attaboy!

Thank you George. I appreciate it.

kharp1

Ummm, can I put my name on the list for when this goes for sale??

george daniel

kharp1 wrote: »

Ummm, can I put my name on the list for when this goes for sale??

I would be surprised if this amp has not found a good home for some time

tonyb

kharp1 wrote: »

Ummm, can I put my name on the list for when this goes for sale??

This might be one of those "You'll have to pry it out of my cold dead hands first" things. OTL's have an addictive sound to them, once you hear them you start comparing everything else to them. I think Bob found a new friend.

Still like to hear some comparisons Bob....inquiring minds and all that.

JuanR

Has anyone ever substituted an 5751 tube for 12AX7 in a Joule phono stage? I talked to Rich Brkich and he said he never done so and probably wouldn't try it, but I said the only difference was the gain in each tube 5751 = 70 and 12aX7 = 100
I was kind of getting the hint that he wasn't sure himself but errored on the side of caution...

I read that Mr. Barber used the 5751 because it was low in microphonics, lower noise floor etc. and used the Power Supply to be the workhorse, but that doesn't mean I couldn't substitute a 12AX7 tube right? I do not know what the circuit was designed for...

I have to look at what each tube draws..etc...

anyone know if it can be done or have done it?

OPS-1 phono stage

heiney9

There are only a handful of 12AX7's that are better in the phono section than the 5751, especially the early GE, Sylvania, Raytheon black plates. Generally the 5751 is quieter and more robust, less microphonic....which really benefits the delicate phono section.

As a general rule 5751's are interchangeable with the 12AX7/ECC83, but not sure the other way around. Given the quality of parts and build of the Joule, it probably would be alright......................but.............

H9

tonyb

I've read just about every Joule review or questions asked, some answered by Judd himself. I can't speak for the phono stage but as pre amp tubes he wasn't keen on the switch and some who have tried the 12ax7 swap didn't care too much for it either.

Judd was very specific in the tubes he used. He claimed to have tried many variations with different tubes to see what sounded best with his circuit designs. He obviously loved the NOS 5751 and 6350's blackplates in his pre's.

Does that mean you can't try it ? No....but given the gain difference you may experience some negative effects. Is there something about the sound your getting that makes you think a different tube should be sought after ?

WagnerRC

Snow shipped me a sleeve of bugle boys along with the tube tester. Thanks again Dan.

This amp has not sounded better and it is really good. Just got done listening to "the wall" damn that was fun. The base was so damn impressive.

Loving this amp more every day.