Montgomery Ward Post-Valco G9131A

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Cygnus X1
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Montgomery Ward Post-Valco G9131A

Post by Cygnus X1 »

From what I could find the Montgomery Airline amps were made by Danelectro in the early 60's then by Valco (think Silvertone) later in the decade until they closed shop.
Then someone...not sure who, used the remaining Valco inventory to continue making the Airlines for a couple of years.
That's where this amp falls in.
Construction is simply stunning.
Point to point using terminal strip risers.
(4)x12AX7, 6V6 Reverb tube (!), (2)x 6L6GC power.
To say the reverb on this is full and lush is an understatement!

For fans of Fender early silverface Twins, this is your gal.
But she won't break up no matter what...I tried!
Used high gain 12AX7's but all that did was increase volume a bit.
It is cathode biased, SS rectified.
B+ is only 385V so it runs a bit on the cold side...it really should break up but I couldn't get it to except some from driving the speakers.

And the vibrato, oh my.
Same design as the first Fender brownfaces and I think Magnatone, vari-bias.

Work summary:
Kept the cans in place (disconnected) and mounted new caps on lexan.
Plus one other 47uf, fresh paired cathode resistors and bias cap.
Replaced a dodgy cap on the reverb and left the rest of them alone.
Reattached one spring in the reverb tank.
Replaced volume pot on channel 1.
Clipped the death cap off.
Installed three prong cord.
Connected a channel bridge on the switch that was "Line Reverse", not needed after safety upgrade.

Pic...dig the dashboard lights!

(I can't get this image to post...what am I doing wrong)?

[img]http:770:450]http://img856.imageshack.us/img856/4661 ... negut1.jpg[/img]
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Structo
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Re: Montgomery Ward Post-Valco G9131A

Post by Structo »

Sweet amp.

Strange about the headroom, they actually got something right!
Only us deranged rock musicians want that distorted overdriven tone!

I have been having problems with posting pictures as well.
Tom

Don't let that smoke out!
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Cygnus X1
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Re: Montgomery Ward Post-Valco G9131A

Post by Cygnus X1 »

Here is the URL, but it won't post as an image.
Same source as most of my others.


Image
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rp
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Re: Montgomery Ward Post-Valco G9131A

Post by rp »

OK, sounds great and super headroom and practically all ceramic caps - it doesn't look like they are only on the rev and vib part. Has a whole new world just opened up? Anyone wanna try building an all disc cap amp or subbing discs on an amp they got and report back?
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Lonely Raven
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Re: Montgomery Ward Post-Valco G9131A

Post by Lonely Raven »

Wow that's a lot of ceramic discs!

That would be a fun project to clone, and experiment with some nice modern caps.
Jack of all Trades,
Master of None
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Cygnus X1
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Re: Montgomery Ward Post-Valco G9131A

Post by Cygnus X1 »

Yes, that's a question.
Sometimes we get too wrapped up in some details that might not mean much in the end?

"Tales from the Tone Lounge" comes to mind.
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Cygnus X1
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Re: Montgomery Ward Post-Valco G9131A

Post by Cygnus X1 »

Update.
In between six other pressing jobs, I finally nailed this down due to the reverb noise issue.
Rotated the tank 180 degrees and it solved the issue.
Common sense should have clued me in but it was a post here that got me to consider it.

Sounds great, better than new!

Some pics of the face, those lights...and the subbed in filter caps.
You can see one new paralleled ceramic on the cathode bias where I tweaked it a little.
I think I ended up at 330 ohm, can't recall just now.
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David Root
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Re: Montgomery Ward Post-Valco G9131A

Post by David Root »

Not seen that type of layout before, very economical but so much better organized than rat's nest point to point.
boots
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Re: Montgomery Ward Post-Valco G9131A

Post by boots »

I'm waiting for ceramic disc caps to come back into favor. If they do, I have a ton of them, and maybe they wil sell for NOS prices!

I haven't used them in a guitar amp, but if someone wants to try it, I will supply you with the caps.
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