[Vintage-Audio] 7591 replacements

Tue Jun 4 14:10:00 2002

In this case, the Scott LK-72 is a rack mount. Doable?

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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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