Rev.2 Trouble in Paradise... (PROJECT NEAR COMPLETION!!)

[Ventura]

Just a heads up to any Rev.2 lovers, mine's a circa 2000/2001 serial number 155

Been "trying" to re-tube this puppy for last couple of weeks - first up was the JJ EL34-II quad, which V7 popped and detroyed within 5min (also seems to have taken out my Bias-Rite socket, it's going in for repair too), and then secondly, fresh quad of JJ KT77s and within 20min the V7 tube popped and fizzled.

Seems it's a component - so she's going to see Ho in Vancouver
Likely a grid resistor or what not.
FAAAAAAAAAAAAAAAK!!!!

 

[maddnotez]

Damn, this is bad.

Makes me want to keep my stock tubes from 13 years ago in there :/

 

[Ventura]

Damn, this is bad.

Makes me want to keep my stock tubes from 13 years ago in there :/

Let me guess - you've got the rebranded EL34 Tesla's in there called ARS?? And straight up 12AX7 CHINESE tubes in there??

That's what I pulled from mine because, well, hey, they were 15 years old and pretty hissy and noisy overall. All new glass. Process commenced and whaddya know, a rabbit-hole has presented itself. Weber Bias-Rite popped cylinder - 2 new tubes from 2 new quads, shot - now a trip to the tech to see if it's the socket, and if it's the socket it'll likely be all 4 sockets.

Ya, looking back now in hindsight the amp sounded JUST F*CKING FINE with them ancient tubes

Gear...

And F*CK YOU Fractal Audio and all your ease-of-use simplicity and zero hassles holier than thou bullshit

 

[leib10]

Hope it works out!

 

[maddnotez]

Damn, this is bad.

Makes me want to keep my stock tubes from 13 years ago in there :/

Let me guess - you've got the rebranded EL34 Tesla's in there called ARS?? And straight up 12AX7 CHINESE tubes in there??

That's what I pulled from mine because, well, hey, they were 15 years old and pretty hissy and noisy overall. All new glass. Process commenced and whaddya know, a rabbit-hole has presented itself. Weber Bias-Rite popped cylinder - 2 new tubes from 2 new quads, shot - now a trip to the tech to see if it's the socket, and if it's the socket it'll likely be all 4 sockets.

Ya, looking back now in hindsight the amp sounded JUST F*CKING FINE with them ancient tubes

Gear...

And F*CK YOU Fractal Audio and all your ease-of-use simplicity and zero hassles holier than thou bullshit

Yep those are the ones.

Maybe I should start with pre amp tubes one at a time for now. Bad deal man sorry to hear.

 

[Ventura]

Yep those are the ones.

Maybe I should start with pre amp tubes one at a time for now. Bad deal man sorry to hear.

Well, I'd not be scared of it - really, I mean, it's gonna need doing one day and if that day is tomorrow and the problem presents itself, get it fixed in the now and you're back on track. I'm glad I found out sooner than later, woulda sucked to box this thing up to a jam or gig and have it go on me, or be in a place where tech service is non-existent.

Not to mention, you're in the States if my memory serves me correct... A ship direct to Bogner HQ could prove very very fruitful if something goes sideways. I am so tempted to send mine down there, but the shipping and customs costs are over-the-top prohibitive (what was this free-trade thing we signed, like, back in the 80s?!?!?!).

I'd give'er... Just see what happens. New glass - V1 to V10 and don't look back. Dive in!!

 

[maddnotez]

Yep those are the ones.

Maybe I should start with pre amp tubes one at a time for now. Bad deal man sorry to hear.

Well, I'd not be scared of it - really, I mean, it's gonna need doing one day and if that day is tomorrow and the problem presents itself, get it fixed in the now and you're back on track. I'm glad I found out sooner than later, woulda sucked to box this thing up to a jam or gig and have it go on me, or be in a place where tech service is non-existent.

Not to mention, you're in the States if my memory serves me correct... A ship direct to Bogner HQ could prove very very fruitful if something goes sideways. I am so tempted to send mine down there, but the shipping and customs costs are over-the-top prohibitive (what was this free-trade thing we signed, like, back in the 80s?!?!?!).

I'd give'er... Just see what happens. New glass - V1 to V10 and don't look back. Dive in!!

Good points. I've been watching eBay for the right deal on some old mullards, amperex, RCA or something like that for some pres.

Still debating on which power tubes. I keep going back and forth between JJE34L and EH6CA7.

 

[Ventura]

Hit ValveQueen Laura up, ask for high pV select tubes for the power section (a lot of cats dig the E34L but I'm keen to step outside and give EL34-IIs and 77s a shot - both by JJ due to their inherent power handling capabilities). As for preamp glass - seriously save your funds and keep it simple. This amp loves simple - maybe an LPS in the PI and your choice in V1 for quietness vs initial gain; but after that it's just a massacre at the signal level


Keep us posted!!

 

[Ventura]

...I liked my little "issue".

It had me off to see Grand Master Ho in Vancouver's east side. Aside from his usual wondrous character - he loved the amp (made definite mention of the high level of hand soldered work underneath the chassis, etc.) - chuckled away as he watched the Rev.2's "clean" channel deliver perfect sin waves on his oscilloscope; and watched the wave get utterly butchered as it was sent through the 2nd channel

Anyway - 540pV with a bias max of 40V just won't cut it. Said only 10% of tubes selected for this job will make the grade - crank it loud enough and they'll die. I've been cranking it - the tube's be dying - grid resistor was perfect.

So? He upped the bias voltage ceiling to 60V (still well within given range as there's just over 73V on tap with the current circuit), loaded some match EH6550s, and biased it to 32mA

Said to "rrawtch out - eet roll bee berry puckeen lowd"

Stay tuned for the post-pant-flappin update

 

[rottingcorpse]

Ok,now I am super interested. I want one of these pretty badly,and can't wait to know how it sounds now set up to these specs.

 

[leib10]

Hmmm... 6550s in a Rev 2. Interesting!

 

[Ventura]

Hmmm... 6550s in a Rev 2. Interesting!

Gonna find out how she sounds in the next hour and a bit

PEACE!!!!

 

[John4021]

....and???

 

[RockyStar]

I love 6550's and I love the Uberschall. Hmmm......

 

[xXDaveyJonesXx]

...I liked my little "issue".

It had me off to see Grand Master Ho in Vancouver's east side. Aside from his usual wondrous character - he loved the amp (made definite mention of the high level of hand soldered work underneath the chassis, etc.) - chuckled away as he watched the Rev.2's "clean" channel deliver perfect sin waves on his oscilloscope; and watched the wave get utterly butchered as it was sent through the 2nd channel

Anyway - 540pV with a bias max of 40V just won't cut it. Said only 10% of tubes selected for this job will make the grade - crank it loud enough and they'll die. I've been cranking it - the tube's be dying - grid resistor was perfect.

So? He upped the bias voltage ceiling to 60V (still well within given range as there's just over 73V on tap with the current circuit), loaded some match EH6550s, and biased it to 32mA

Said to "rrawtch out - eet roll bee berry puckeen lowd"

Stay tuned for the post-pant-flappin update

And this is before slamming it with your 48v MK. Jaaayzuz.

Staying tuned!

 

[Ventura]

Incredible.

Just going back for one minor adjustment to Master Ho's and I'll give y'all the full rundown.

I'm up to something here

Stay tuned.

 

[leib10]

Nice, keep up updated!

 

[Ventura]

By the way, the JJ preamps in the case 5751 are just fine for the application of reigning back the gain... Cheaper than the Jan-GE or Jan-Philips options. It's a functional tube - no need for high-brow glass.

And this coming from a guy who can't stand JJ's in general

Cheers,
Mo

 

[Ventura]

Home stretch - everything's been done. Just sorting through a few preamp bottle options and the mighty Rev.2 will rock like none other I've stood before pants a flappin

Pics, shitty iPhone clips, everything coming up... Ch.1 actually sounds incredibly good (ya, channel one - the "what's this channel for" channel). Warm, spanking, percussive, full. Loving it on my neck pups on the Lester, very clean and smoooooooooth

 

[leib10]

Cool, keep us updated!