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'Watchmaster to Guitar Amp '
Author:Danny Knapp (registered user: 5 posts )
Date: Sat, Mar 18th, 2017 @ 18:34 ( . )

Hello,

I'm a newb to tube amps, I stumbled across Uncle Doug's youtube channel looking for tolexing cabinet tutorials. He was such a great teacher I kept watching his amp vids and started reading and found this forum.

I've been looking for something to get my hands on with some tubes, I even thought about hacking up an organ ! But then I watched these two videos by Guitologist.

[link]
[link]

and it gave me the idea that old watch timers have tubes.

So I went on eBay and found a Watchmaster G-11, took a chance on it after I found a schematic. It's a pretty neat machine, I think the chassis will serve as an amp head without much work, the sockets look in good shape. I will have to test the tubes and figure out if I can use the power transformers it came with.

I'll post up a video of it later, but the tubes it comes with is

2 - 6SJ7
1 - 2050
2 - 6SN7
1 - OD3 (VR-150)
1 - 6L6GB
1 - 5V4GA

It also has two toggle switches, a light with red jewel, one pot with cool knob, and a headphone jack mounted on a control panel.

My goal is to create a new circuit for a guitar amp using the tubes, transformers, similar filter cap. I'll have to add a speaker jack and probably a few pots.

So the 6L6GB for power tube, 5V4GA rectifier, 2 - 6SN7 preamp (if possible, or substitute 6SL7), I would like to incorporate the OD3 to supply voltage to preamp plates, at least try it.

I should probably quit there, but tempted to do something with the 2050. Saw one article how to make a zener regulator with it to make 12V, maybe I can do 6 ?

I don't have any plan for the 2 - 6SJ7 spots, IDK I guess I could try to make a tremolo or something.

Anyways, I'm in way over my head which is usually my learning style anyways. I give myself about a 50/50 chance of burning or blowing something up, but I'm learning a lot and having fun so far.

I'm open to suggestion, still in brainstorming mode so please share any ideas you might have. thanks !

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'Watchmaster to Guitar Amp '
Author:Stephen Keller (registered user: 6270 posts )
Date: Sat, Mar 18th, 2017 @ 21:13 ( . )

Hi Danny,

Can you post a schematic of the Watchmaster G-11 circuit? I'd like to see what you have to work with.

Thanks,

Stph

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'Watchmaster to Guitar Amp '
Author:Danny Knapp (registered user: 5 posts )
Date: Sat, Mar 18th, 2017 @ 22:20 ( . )

Stephen,

Does Google Drive work okay on here ? If so, here is a link.

[link]

If not, let me know what is the commonly used site for sharing.

DK

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'Watchmaster to Guitar Amp '
Author:Stephen Keller (registered user: 6270 posts )
Date: Sun, Mar 19th, 2017 @ 00:11 ( . )

Google Drive works. People use all sorts of file sharing services here. The main thing is to avoid authenticated access.

I'll take a look at the schematic more closely tomorrow. It looks like good bones, though. The 6SN7s are nice tubes and having two of them makes for nice high-gain builds because they don't require don't need as much soul-sucking inter-stage attenuation.

Stph

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'video/schematic'
Author:Danny Knapp (registered user: 5 posts )
Date: Sun, Mar 19th, 2017 @ 05:10 ( . )

here is a video [link]

here is a much clearer schematic [link]

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'power transformer, schematics'
Author:Danny Knapp (registered user: 5 posts )
Date: Thu, Mar 23rd, 2017 @ 00:50 ( . )

Concerning the power transformer, the good news is it's an excellent transformer well suited for a guitar amp as best I can tell.

What I've found is that it has your 6.3V and 5V supplies with center taps. These should be good to go as they already power more in this application than they will in the amp.

The secondary power also looks to be well suited, it even has the 475v bias tap !

I have been unable to test or find specifics on amperage, but we can see in the application as a watch timer it must be fairly sufficient. I can also see that the dimensions 4-1/8" x 3-1/4" x 3-7/8" and the weight 5lb - 15oz makes it very similarly sized to Hammond and Classic Tone transformers in the range for 30-50 watt amps. I suspect it outputs 150-200 amps.

Now the bad news, wires are extremely brittle, bare in spots, and a few came loose from the coil as I was examining it. I really don't want to test my luck or ability to rebuild this transformer. If anyone would like to give it a go I'd be happy to send it to you.

The other smaller transformer sent power to a 115V electric motor so it's not of use for me.

I have a complete schematic, will upload and attach links shortly.

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'power transformer, schematics'
Author:Danny Knapp (registered user: 5 posts )
Date: Thu, Mar 23rd, 2017 @ 02:49 ( . )

I lied, I don't have a complete schematic yet ! Here is the preamp section, I'm making some adjustments to the other parts.

[link]

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