[Vintage-Audio] 7591 replacements

Tue Jun 4 14:30:01 2002

The 6L6gt/gc was mil spec, was it not? Much larger and I think the amplification
characteristics were somewhat different.	

Duane W8DBF	

----------
From: Helmut Usbeck <[email protected]>
To: [email protected]; Duane Fischer, W8DBF <[email protected]>
Subject: Re: [Vintage-Audio] 7591 replacements
Date: Tuesday, June 04, 2002 2:16 PM

Quite doable, if space is no problem, also check out an adapter plate which 
was made for a Mac 225.  Very professional looking.  Don't agree with the 
author using 6L6's and such.  Article in AudioExpress May, 2002.

> In this case, the Scott LK-72 is a rack mount. Doable?
>
> ----------
> From: JM/CO <[email protected]>
> To: [email protected]
> Subject: Re: [Vintage-Audio] 7591 replacements
> Date: Tuesday, June 04, 2002 1:37 PM
>
> I would agree on your speculation that the Russian 7591-A types are
> re-based 6L6 types. This would surely account for the larger envelope. AES
> sells an adapter that allows the direct plug in of the type 6GM5. This type
> IS electrically identical to the 7591-A, but the tube, together with the
> adapter, will not fit inside the case of Scott amps. If the case / general
> appearance is not an issue, this is a great solution. Also agree with your
> comments regarding voltages / currents of 6L6 / 5881 types. Requires more
> than simple mods. Not a project for the faint hearted.
> Chuck N1LNH
> -----Original Message-----
> From: Helmut Usbeck <[email protected]>
> To: [email protected] <[email protected]>
> Date: Tuesday, June 04, 2002 1:04 PM
> Subject: [Vintage-Audio] 7591 replacements
>
> >I'm surprised nobody offered up the 6GM5 in place of a 7591.  I've done
> >several conversions in Fisher 500 receivers, plus my Pilot amp.  It's
> >electronically exactly like a 7591 but uses a 9 pin "magnovar" socket.
>
> It's
>
> >about 2 tens of an inch taller, so what one does is drop the socket with
>
> 1/4
>
> >inch spacers lower in the chassis.  Wire it up and away you go, along with
> >fitting under the cover.
> >By the way using 5880's, 6L6's and other beam power pentodes is not a good
> >idea because they all draw more plate and filement current than does a
>
> 7591.
>
> >If you think 7591's are expensive try getting your hands on power and
>
> output
>
> >transformers for these older sets.  Also if one doesn't adjust the bias
> > for these other "replacement" tubes in question the fidelity can suffer
> > also. 6GM5's go from $5.00-25.00 new.  I have no experence using the
> > Sovtek
>
> tubes.
>
> >The electronic specs on them indicate they are not a 7591 equivilent.  On
> >paper looks like a rebased 6L6 or thereabouts.
> >
> >Regards,
> >Helm.  WB2ADT
> >_______________________________________________
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> >List Administrator: Duane Fischer, W8DBF
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>
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