Does an UBERSCHALL need to be biased?

[Dark Aardvark]

Hello all . . . I will soon be the proud owner of an Uberschall and apparently it had just been re-tubed. My question has already been asked in the "subject" line but I'll repeat it . . . "Does a Bogner Uberschall need to be biased??"

The Ecstasy 101B that I just bought from Chuck has been biased and sounds awesome and I must confess that it's all very new to me, as I'd never had amps that required being "biased" before. So!! What do you think?

As always, thank you. -J

 

[zewango]

Yes it does Newer Uber's make it real easy with external bias points.

 

[Dark Aardvark]

Allright . . . so be it then.

This one is "Revison Blue" so I'm not exactly sure how old it is. Based upon when the guy bought it originally, I am going to guess that's probably a 2007 but I'm not sure until we see the serial number on it. The guy that owned it bought it new and he's only about 19 . . . it can only be so old!! ha ha

 

[steve_k]

Allright . . . so be it then.

This one is "Revison Blue" so I'm not exactly sure how old it is. Based upon when the guy bought it originally, I am going to guess that's probably a 2007 but I'm not sure until we see the serial number on it. The guy that owned it bought it new and he's only about 19 . . . it can only be so old!! ha ha

Yep, just snatch the back grill off and use a digital MM and probes. Only thing is there is only one bias adjustment for all 4 tubes. If the guy put in a well matched quad, then they will bias pretty close with the one adjustment. Otherwise, expect a few mA difference from all 4 after your first tube is biased.

Steve

 

[Dark Aardvark]

I think Chuck is going to help me with that once it arrives . . . which it might have . . . I'm in session and haven't "came up to the surface" to see what's arrived today. Thanks though!!! I'm EXCITED!!!

Nothing like MORE GAIN THAN SHOULD BE LEGAL!!! WHOOOOOOOOOOOOOOOOO

 

[Ventura]

What model year did Bogner start placing external, accessible bias trims on the chassis for the Uberschall?? I'm awaiting this new-in-box 2007 Uberschall, so I'm wondering if it too has the external trim pot to bias the tubes.

And while we're on the topic - I take it the Ubeer runs EL34's and I've heard it's very finicky as to brands of tubes for both the power section as well as its preamp section. What's the reading one should strive for when biasing new EL34's on an Uber??

Namaste,
V.

 

[steve_k]

What model year did Bogner start placing external, accessible bias trims on the chassis for the Uberschall?? I'm awaiting this new-in-box 2007 Uberschall, so I'm wondering if it too has the external trim pot to bias the tubes.

And while we're on the topic - I take it the Ubeer runs EL34's and I've heard it's very finicky as to brands of tubes for both the power section as well as its preamp section. What's the reading one should strive for when biasing new EL34's on an Uber??

Namaste,
V.

I think the external bias came with the blue rev. in 2006. Not sure though.

Stay with 34's in the Uber. I use SED Winged C's in mine, and every other amp I own. The Uber is very gainy and the V1 preamp tube needs something a little special. I use a Tung Sol 12AX7 Reissue in V1 cause it has good microphonics and not much noise. I found that running typical Sino or Russian standards in V1 that it can get a little noisy. The TS takes care of that. For the other preamp tubes, the cheapest thing on the market (Chinese, Sovteks, etc) will do.

I read where the new Ruby EL34 BHT's are geared up nice for the Bogners. They handle about 600V.

Steve