Need 6973 or substitute for Magnatone Amp
Paul Cassone
Yes, it's true. I have a Magnatone Custom 450 amp with weak 6973's.
I've seen them in catalogues, but they're ridiculously expensive.
The amp's kinda beat. Any suggestions for substitutes welcome, or leads
on reasonable 6973's.
Thanks and regards,
Paul
Peter Russell
I use 6CM6(9 pin 6V6) as a sub in a Bogen reciever. It is a bit less
power output but sounds OK. I think that the 6CZ6 is the same as 6973,
better double check me though.
--
Peter Russell pe...@goldaero.com
Fidelis Audio Company
http://www.goldaero.com/audio/fidelis/fidelis.html
wboyd...@aol.com
I believe the 6973 socket can be rewired to accept 7591's which are very
soon to be released by Svetlana. That would be my choice. I have a
Sherwood s5500 amp I love with those tubes and that is my plan.
Let me know how it turns out - those Magnatones were wonderful sounding
things!
I'm kinda lookin for one if you decide to sell or run across another.
Bill Boyd
Adam Stouffer
The 6973 is just a higher voltage 6BQ5/EL84. you can use low cost
6BQ5's but just make sure the plate voltage is below about 350 volts.
Adam.
Mr. Steven Bender
Someone wrote:
The 6973 is just a higher voltage 6BQ5/EL84. you can use low cost
6BQ5's but just make sure the plate voltage is below about 350 volts.
Adam.
That is W-R-O-N-G. Sometimes the 7189 is usable as a sub for the 6BQ5,
and vica-versa, but the above tubes have very different pinouts, only
the heaters pins 4/5 are the same. Plug in a 6BQ5 ( 9CV ) for the 6973
( 9EU pinout ) and you'll destroy the amp and the tubes...
I do have one NOS pair of 6973's available, for the right offer,
BTW.
Steven L. Bender
Davin Carter
Kenneth A. MacKay, P. Eng. wrote:
>
> Yeah the 6873 has no direct sub....
I have about 24 slightly used 6973s
Davub Carter at rus...@ix.netcom.com
Kenneth A. MacKay, P. Eng.
Kevin Kennedy
In article <328EAC...@mail.sgi.net>, te...@mail.sgi.net says...
> wboyd...@aol.com wrote:
> >
> > I believe the 6973 socket can be rewired to accept 7591's which are very
> > soon to be released by Svetlana. That would be my choice. I have a
> > Sherwood s5500 amp I love with those tubes and that is my plan.
> >
> > Let me know how it turns out - those Magnatones were wonderful sounding
> > things!
> >
> > I'm kinda lookin for one if you decide to sell or run across another.
> >
> > Bill Boyd
>
> 6BQ5's but just make sure the plate voltage is below about 350 volts.
>
> Adam.
>
completely non-interchangeable. Actually the 6973 is not all similar to
the 6BQ5, the filament current, plate ratings, Rp, and pinout are all
different. See the following:
Pin# 6973 6BQ5
1 G2 NC
2 NC G1
3 G1 G3/Cathode
4 F F
5 F F
6 G1 NC
7 G3/C PLATE
8 G2 NC
9 PLATE G2
Filament current for a 6BQ5 is 760mA vs. 450mA for the 6973
Rp is 38K for a 6BQ5, and twice this for a 6973, not coincidentally the
6973 requires twice the bias voltage and drive for a given operating
condition. Plate dissipations are similar, plate voltage ratings are not
with the 6973 rated at 440V pentode connected. Plate loads can be
similar.
It would be possible to make the requisite changes to use 6BQ5 only if
plate voltage is below 330V, and the filament transformer can handle the
additional current.
Regards, Kevin K.
--
Check out my website at http://www.ultranet.com/~kennedyk
or projects, articles, useful links, and information on
tube hifi.
Stephen G. Matzuk
cyc...@interlog.com (Kenneth A. MacKay, P. Eng.) wrote:
>Yeah the 6873 has no direct sub....
>
>
>EXQ...@prodigy.com (Mr. Steven Bender) wrote:
>
>>Someone wrote:
>
>>6BQ5's but just make sure the plate voltage is below about 350 volts.
>
>>Adam.
>
>
Roger that.
The 6973 is most similar to 6AQ5/6V6/7408 family, but higher plate voltage.
Figure out plate dissipation limitations, and pick one.
You're probably not running too far above max plate voltage (350V).
BTW, they are 7-pin, octal and octal socketed, respectively.
Lots of luck
-Steve
wboyd...@aol.com
I wrote a correction some days ago to my first post when I realized what I
had done - was thinking of the 7868's in my sherwood & somehow got them
mixed up - SORRY FOR MY CONFUSION. My correction does not seem to show
up on the NG for some reason. What I did point out was that the Magnatone
6973 amps show plate voltages of 400V orhigher and 10,000 ohms on the OPT
primary. The impedance should be OK but dont think any 6BQ5 would work
without burning up.
Maybe a 7189 (or possibly the Sovtek EL84M?)
Also, I think the sockets would need rewiring & bias checked.