The 6AQ5 is designed to work with 250V on the plates, and was operating at reduced efficiency in the
2-B.
By the time the 4 Series was designed, the 6EH5 was introduced, and was
designed for 150V plate supply.
A tube amplifier Class operated A sounds so much smoother than any solid state discrete or IC audio
amplifier. Combine that with the low distortion of the L/C IF filters, and you have a receiver that
you can listen to all day without fatigue. By comparison, a receiver with hard edged crystal
filters with their phase distortion and group delay, fed through a solid-state amp, and you're good
for a headache in an hour...
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
Neil M Califano wrote:
Why didn't Drake use the 6AQ5 in the R4A? I read the tube performs as well as
much larger ones. Also, could the 6AQ5 account for the pleasant tone of the 2-B?
--- On Thu, 8/25/11, Garey Barrell<[email protected]> wrote:
From: Garey Barrell<[email protected]>
Subject: Re: [Drakelist] AF output tube in R4A
To: "drakelist"<[email protected]>
Date: Thursday, August 25, 2011, 5:30 PM
No. The 2-B uses the 6AQ5 and
the R-4 Series all use the 6EH5.
The 6EH5 is not a Beam Power Pentode, the 6AQ5 is.
The third 'grid' in a Pentode can be either a spiral
wrapped grid like the other two, OR it can be
'plates' that 'focuses' the electron beam more fully on the
Plate. Primary result is greater power
capability as a result of 'all' Cathode current reaching
the Plate.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
Neil M Califano wrote:
Is the AF output tube in the R4A swappable with the
same tube in the 2-B? I Googled but it is not clear. Btw,
what is a beam pentode or tetrode? Is 6EH5 in V7 one of
these?
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