Guild Masteramp (Tweed?) Schematic Help

[martin manning]

Here's the info you need to read the molded caps: http://www.tpub.com/neets/book2/3g.htm Looks like you have two types of codes there, the solid arrow and the broken arrow.

Does this look right?
510pf mica 20% for the first pic, 1000pf mica 3% for the second pic.[/code]

First one with broken arrow: Value = Green, Brown, Brown = 510pF, Tolerance = black = 20%

Second ones with solid arrow: Value = brown, black, orange = 10,000pF (0.01uF), Tolerance = red = 3%.

[martin manning]

Pin 5 of the rectifier is connected to the bottom terminal of the orange rectifier and also connected to the 80uf positive (+) can cap. The top terminal of the orange rectifier is connected through a 10ohm resistor to the negative (-) of the multi-cap can labled MC1.

Pin 2 is connected through the 100ohm resistor to the small rectifier negative (-). Pin 2 is also connected to the negative (-) of the above mentioned can cap as well as one side of the AC and filament tx. The positive (+) of the small rectifier is connected to V5-4 and V4-4 and filtered by the 80uf of the multi-cap can MC1.

Also, the negative (-) on neither the single cap can nor the multi-cap can are not connected to the chassis. Both are showing about 40k to the chassis. There are very few wires to the chassis ground as well as all of the pots and jacks.

Weird too, the bypass switch grounds out the signal at the output jack to the chassis. I don't think I've ever seen that before.

Sorry if I'm confusing you. I've never had to work with a supply like this... so your help is much appreciated!

Tony

Pin 5 and pin 2 of the rectifier tube are connected together and to the AC line hot (the side without the fuse and switch).

The neutral side of the AC line (with fuse and switch) is connected to the ground of the multi-cap can. I'll call that circuit ground.

So one side of the orange selenium goes to AC hot and the other side goes through a 100R to circuit ground on the multi-cap?

Then, I get confused: above and in your drawing you have both sides of the 80uF can connected to AC hot. Is it possible that the series chain of 10R, orange selenium, and 80uF are connected across the AC?

[dorrisant]

Pins 2 and 5 of the rectifier are not connected in any way.

Pin 2 of the rectifier is connected to AC hot and the negative (-) of a single cap can while pin 5 is connected to the positive (+) of that same single cap can. Pin 5 is also connected to what I assume is the (+) side of the orange rectifier, through it, through a 10ohm resistor to the negative (-) tap on a multi-cap can which provides negative (-) for that can - with 80uf, 40uf, 20uf and 10uf taps... Clear as mud!!!

Tony

[Structo]

Martin, thanks for the link to Integrated Publishing.

Some good stuff on there.

[martin manning]

Tony, maybe the confusion would clear up if you identified the AC line connections as AC1 and AC2, corresponding to the power cord inlet.

Tom you can also get the whole NEETS manual somewhere too, which is easier to navigate than via that link.

[dorrisant]

Tony, maybe the confusion would clear up if you identified the AC line connections as AC1 and AC2, corresponding to the power cord inlet.

I agree with you there. In my defense there is only 2" of AC cable left because it has been cut off at some point in the not so recent past. There were no indications of polarity at all and I was confused about the fuse being on the neutral. I can totally see your point though.

Tony

[martin manning]

2" is way better than none!

[dorrisant]

2" is way better than none!

Lol!! That made my day!

Tony

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The ribbed/grooved part of the power cord is the hot, I thought. [img:17:16]http://octopusoverlords.com/forum/image ... /think.gif[/img]

Is this a push-pull amp or is it a parallel single-ended amp?

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Pics of my amp.

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More.

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Board and wiring nonsense.

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I was corrected on the Hoffman board, they are RCA speakers. Sorry.

[dorrisant]

Is that the '57?

Tony

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No, that is the 53-54 thing. It does have that inductor in the trem circuit, it was just hidden underneath that foam rubber junk. I'm going to reinstall a multisection cap to replace that tangle of axial and radial caps. The old one was a 10/10/20@450+100@200, but who knows if that was original or not.