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Ty Unes Ty Unes is offline
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Default 6v6 Amp Mystery Pot Question

I have been fixing up this 6v6 amplifier

http://2xl.homelinux.com/riverty/

There are 2 pots located on the top of the amp. One is for balance, the
other is not marked. I'm thinking it's the bias setting? If so, could
someone enlighten me on how to set this properly? If not, could someone
enlighten me as to what the heck it is? I plan on replacing all tubes and
would like to know beforehand. Might save me a tube?

The amp works great and sounds great BTW.

Thank you all for reading.
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Phil Allison Phil Allison is offline
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Default 6v6 Amp Mystery Pot Question


"Ty Unes"
I have been fixing up this 6v6 amplifier

http://2xl.homelinux.com/riverty/

There are 2 pots located on the top of the amp. One is for balance, the
other is not marked. I'm thinking it's the bias setting? If so, could
someone enlighten me on how to set this properly? If not, could someone
enlighten me as to what the heck it is?




** Looks like it is wired in the heater circuit with the wiper going to
chassis.

Makes it a " hum balance" pot.

When the amp is all working, turn up the volume to max a set the pot for
least audible hum.




......... Phil


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David[_4_] David[_4_] is offline
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Default 6v6 Amp Mystery Pot Question

I have a similar amp to this that a friend gave to me. It uses 6EU7's
and 6x4, but I think it is very similar in design. It has a
suprisingly good sound for what it is. I believe mine was from a 1960
console.

My questions for you are. Have you used this "wonderful thing called
Google" to find the schematics of this amp? They are out there... It
will save some head scratching and maybe allow you to do some
diagnosis other than twiddling a tube in a socket.

Have you tested the tubes? Why are you going to spend the $$$ on caps
assuming that will fix the problem? Have you cleaned the sockets?
measured some voltages?

I have toyed with the idea of changing the caps in mine but might only
consider putting orange drops in to see if that helps the sound. This
was a cheap amp that is a wonder of simplicity. You should try to use
the most efficient speakers you can find with it.

David



On 07 Aug 2007 04:35:58 GMT, Ty Unes wrote:

I have been fixing up this 6v6 amplifier

http://2xl.homelinux.com/riverty/

There are 2 pots located on the top of the amp. One is for balance, the
other is not marked. I'm thinking it's the bias setting? If so, could
someone enlighten me on how to set this properly? If not, could someone
enlighten me as to what the heck it is? I plan on replacing all tubes and
would like to know beforehand. Might save me a tube?

The amp works great and sounds great BTW.

Thank you all for reading.


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David[_4_] David[_4_] is offline
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Default 6v6 Amp Mystery Pot Question

I forgot to add that this amp was a good "learning" amp for me and
that I probably only know a fraction of what many on this newsgroup
have already forgotten. This is just to qualify what I said in the
previous post.

David

On Tue, 07 Aug 2007 07:23:41 GMT, David wrote:

I have a similar amp to this that a friend gave to me. It uses 6EU7's
and 6x4, but I think it is very similar in design. It has a
suprisingly good sound for what it is. I believe mine was from a 1960
console.

My questions for you are. Have you used this "wonderful thing called
Google" to find the schematics of this amp? They are out there... It
will save some head scratching and maybe allow you to do some
diagnosis other than twiddling a tube in a socket.

Have you tested the tubes? Why are you going to spend the $$$ on caps
assuming that will fix the problem? Have you cleaned the sockets?
measured some voltages?

I have toyed with the idea of changing the caps in mine but might only
consider putting orange drops in to see if that helps the sound. This
was a cheap amp that is a wonder of simplicity. You should try to use
the most efficient speakers you can find with it.

David



On 07 Aug 2007 04:35:58 GMT, Ty Unes wrote:

I have been fixing up this 6v6 amplifier

http://2xl.homelinux.com/riverty/

There are 2 pots located on the top of the amp. One is for balance, the
other is not marked. I'm thinking it's the bias setting? If so, could
someone enlighten me on how to set this properly? If not, could someone
enlighten me as to what the heck it is? I plan on replacing all tubes and
would like to know beforehand. Might save me a tube?

The amp works great and sounds great BTW.

Thank you all for reading.


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Gerry[_2_] Gerry[_2_] is offline
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Default 6v6 Amp Mystery Pot Question

On Aug 7, 12:35 am, Ty Unes wrote:
I have been fixing up this 6v6 amplifier

http://2xl.homelinux.com/riverty/

There are 2 pots located on the top of the amp. One is for balance, the
other is not marked. I'm thinking it's the bias setting? If so, could
someone enlighten me on how to set this properly? If not, could someone
enlighten me as to what the heck it is? I plan on replacing all tubes and
would like to know beforehand. Might save me a tube?

The amp works great and sounds great BTW.

Thank you all for reading.


If it works great and sounds great, why replace the tubes at all? I
only fiddle with tubes when there is a problem, and then I only swap
them out with spares. If that fixes the problem, fine. If not, then
likely a recap will fix it if that hasn't already been done. However,
lately I've had a few amps that don't sound quite right after a recap,
and so I replace the resistors also. Usually they sound better than
ever afterward.

These are just my experiences and observations, as I am still fairly
new at this myself.

Gerry




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David[_4_] David[_4_] is offline
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Default 6v6 Amp Mystery Pot Question

The Magnavox I was given was in a console until my friend got his
grubbies on it as a kid. Then he abused it as a guitar amp. He told me
he really liked it... Then he said it was in the backyard for a while
before he gave it to me!!! I cleaned it up, tested the tubes and
fired it up. As I mentioned it sounded suprisingly good! The low end
is not really there, but the mids were kinda magic.

My references are Dynaco MkIII's , ST70, Fisher 500C (a favorite) ARC
D76A (another favorite).

I thought that changing the caps might interfere with the "signature"
of this amp. (audiophool talk...) This is taking into consideration
what it is a cheap abused little amp with the 6V6's testing a little
weak here and there. Also, I have better things to throw money at...
Find the real problem with the one channel, fix the component, then
decide if it is worth throwing money at it. Do you have a pair or
really efficient speakers and a subwoofer to match this to for a small
room?

My two cents and then some....

David

On Tue, 07 Aug 2007 05:57:04 -0700, Gerry
wrote:

On Aug 7, 12:35 am, Ty Unes wrote:
I have been fixing up this 6v6 amplifier

http://2xl.homelinux.com/riverty/

There are 2 pots located on the top of the amp. One is for balance, the
other is not marked. I'm thinking it's the bias setting? If so, could
someone enlighten me on how to set this properly? If not, could someone
enlighten me as to what the heck it is? I plan on replacing all tubes and
would like to know beforehand. Might save me a tube?

The amp works great and sounds great BTW.

Thank you all for reading.


If it works great and sounds great, why replace the tubes at all? I
only fiddle with tubes when there is a problem, and then I only swap
them out with spares. If that fixes the problem, fine. If not, then
likely a recap will fix it if that hasn't already been done. However,
lately I've had a few amps that don't sound quite right after a recap,
and so I replace the resistors also. Usually they sound better than
ever afterward.

These are just my experiences and observations, as I am still fairly
new at this myself.

Gerry


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Ty Unes Ty Unes is offline
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Default 6v6 Amp Mystery Pot Question

On Tue, 07 Aug 2007 05:57:04 -0700, Gerry wrote:

On Aug 7, 12:35 am, Ty Unes wrote:
I have been fixing up this 6v6 amplifier

http://2xl.homelinux.com/riverty/

There are 2 pots located on the top of the amp. One is for balance, the
other is not marked. I'm thinking it's the bias setting? If so, could
someone enlighten me on how to set this properly? If not, could someone
enlighten me as to what the heck it is? I plan on replacing all tubes
and would like to know beforehand. Might save me a tube?

The amp works great and sounds great BTW.

Thank you all for reading.


If it works great and sounds great, why replace the tubes at all? I
only fiddle with tubes when there is a problem, and then I only swap
them out with spares. If that fixes the problem, fine. If not, then
likely a recap will fix it if that hasn't already been done. However,
lately I've had a few amps that don't sound quite right after a recap,
and so I replace the resistors also. Usually they sound better than
ever afterward.

These are just my experiences and observations, as I am still fairly new
at this myself.

Gerry


Gerry,

I don't have any spare tubes for this amp as is. I'm not replacing the
tubes because I think they are bad, I want to have a spare set ready
anyway so why not?

About the tubes. I'm thinking about going with new JJ/Tesla 6V6S's and
12AX7's. I know these are not the best audiophillie choices, but I don't
care. I'm a guy that likes playing with bottles on a working joe's
paycheck! $329.00 for a pair of Raytheon Black Sable's is NOT in my price
range. For the rectifier, I thought a Sovtek 5U4GB.

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Ty Unes Ty Unes is offline
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Default 6v6 Amp Mystery Pot Question

On Tue, 07 Aug 2007 07:23:41 +0000, David wrote:

I have a similar amp to this that a friend gave to me. It uses 6EU7's
and 6x4, but I think it is very similar in design. It has a suprisingly
good sound for what it is. I believe mine was from a 1960 console.


Nice.


My questions for you are. Have you used this "wonderful thing called
Google" to find the schematics of this amp? They are out there... It
will save some head scratching and maybe allow you to do some diagnosis
other than twiddling a tube in a socket.


I love Google. And Gmail. and yes, I have. Not found as yet.


Have you tested the tubes? Why are you going to spend the $$$ on caps
assuming that will fix the problem? Have you cleaned the sockets?
measured some voltages?


I'm sorry. I have not found the time to update my blog with the latest
news so you are a few days behind. The amp is fixed and running fine. The
problem was an open resistor on the grid of one of the 12AX7's. I have
already replaced all caps except the power caps. I have the replacements
but I will have to do fairly major surgery to the amp to replace these.
Will be a good "rainy day" project sometime in the future.


I have toyed with the idea of changing the caps in mine but might only
consider putting orange drops in to see if that helps the sound. This
was a cheap amp that is a wonder of simplicity. You should try to use
the most efficient speakers you can find with it.

David


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Tom Bavis Tom Bavis is offline
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Posts: 11
Default 6v6 Amp Mystery Pot Question

On 07 Aug 2007 04:35:58 GMT, Ty Unes wrote:

I have been fixing up this 6v6 amplifier

http://2xl.homelinux.com/riverty/

There are 2 pots located on the top of the amp. One is for balance, the
other is not marked. I'm thinking it's the bias setting? If so, could
someone enlighten me on how to set this properly? If not, could someone
enlighten me as to what the heck it is? I plan on replacing all tubes and
would like to know beforehand. Might save me a tube?

The amp works great and sounds great BTW.

Thank you all for reading.


Magnavox AMP185 can be found in Sams Photofact folder 449-7 (1959).
Check your library - they may be able to get you a copy.

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