Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: SoundCity85 on February 11, 2021, 05:16:35 am

Title: 7591 - what to do with them
Post by: SoundCity85 on February 11, 2021, 05:16:35 am

Any good ideas? I just found a quad of NIB branded ITT 7591 in a large tube collection I bought for next to nothing. Can they be used as replacements for EL34 where plate voltage isn't too high? Cheers

Title: Re: 7591 - what to do with them
Post by: HotBluePlates on February 11, 2021, 07:36:27 am

Quote from: SoundCity85 on February 11, 2021, 05:16:35 am

... 7591 ... Can they be used as replacements for EL34 where plate voltage isn't too high? ...

Not really, as the 7591 is a 19w tube and the EL34 is a 25w tube.  You'd expect the power supply & loading of the EL34-circuit to attempt to pull more current than the 7591 can deliver without overheating.

It's kind of a very-early (19w) 6L6, that only needs about as much drive voltage as an EL34, in a 6V6-sized package.  It's a bit of its own animal.

Quote from: SoundCity85 on February 11, 2021, 05:16:35 am

Any good ideas? ...

Ampeg (and maybe others) made lots of 7591 amplifiers.

Title: Re: 7591 - what to do with them
Post by: J Fletcher on February 11, 2021, 11:18:06 am

 If it was me , I would sell the quad to a hifi buff who can use them . They go for big $$$ , and a quad would be very desirable for a tube stereo amp . Fishers I believe , amongst others .

Title: Re: 7591 - what to do with them
Post by: TitaniumValhalla on February 11, 2021, 11:20:36 am

Gibson used them in a couple of different amps in the mid-60's. I really like the way they sound when overdriven in the '64-'65 GA-25RVT, after a few circuit mods.

NOS 7591's seem to be relatively expensive, probably because of the hi-fi crowd who are its primary user these days, though JJ and New Sensor make new production tubes that sound fine.

Title: Re: 7591 - what to do with them
Post by: jordan86 on February 11, 2021, 11:25:55 am

I have a buddy on here who may be interested, @DBork. He just picked up an old univox amp that uses 7591's.

Title: Re: 7591 - what to do with them
Post by: mmrxcsr01 on February 11, 2021, 05:58:17 pm

How about a Premier Twin 8 build?

Title: Re: 7591 - what to do with them
Post by: SoundCity85 on February 12, 2021, 02:07:34 am

1 getter flash was white, so a leaky tube for the bin. So only 3 tubes instead of 4 :(

Title: Re: 7591 - what to do with them
Post by: DummyLoad on February 13, 2021, 02:30:24 am

Quote from: SoundCity85 on February 12, 2021, 02:07:34 am

1 getter flash was white, so a leaky tube for the bin. So only 3 tubes instead of 4 :(

reverbrocket clone and a SE of some sorts?  :icon_biggrin: 

consider sale to a Hi-Fi guy to keep an Eico chugging along.

--pete

Title: Re: 7591 - what to do with them
Post by: dude on February 13, 2021, 01:12:10 pm

I fixed an old oddball SE running a 7591, sounded great, maybe sell one pair, SE for the other  :icon_biggrin: .

Title: Re: 7591 - what to do with them
Post by: SoundCity85 on February 15, 2021, 02:06:29 am

yeah I agree, too many things on my plate to mess around with these