100 Watt Master Volume instructions

[VelvetGeorge]

A low resolution version is available for download here:

DOWNLOAD HERE

Approximately 12mb. The full resolution, 59 page instructions are over 70mb and available on CD or printed manual.

Update July 13, 2009. Version 1.1

Notes: updates to text, typos and bill of materials.



george

[frank9310]

Hi George,

Can you tell me if that's the same MV as the one Trower's amp tech shows here? http://forums.vintageamps.com/viewtopic ... er#p656608" onclick="window.open(this.href);return false;

The switches look different but did all the ones from 76-80 pretty much sound the same? Thanks.

[demonufo]

They're all exactly the same. The only thing that changed between those years, is the headcab almost immediately after they came out (switched to white piping with corner protectors) then the switches changed to rocker switches in '77.
After that the only things that changed were the brands of signal capacitors used.

[neikeel]

I have a '77 JMP50 (Lead Model 1987).

I bought it after it had been recovered in felt and the board had a cascade mod.
Its spec. was pretty standard lead with green bean type coupling caps, mustards for 0.0022 coupler and a 5k presence pot with 0.68mustard cap/4k7 resistor. NFB was 100k. The cosmetics were elephant tolex medium logo, black bat switches, thick head box sides with white piping only on the middle of the front panel and corner protectors. As I wanted a '72 at he time I put a metro board in, thinned the sides down and recovered it in levant with small logo

It has always sounded good in its present format but I now have a couple of clean Smallboxes and a stash of 100watters as well as a '77 AP1982 cab in elephant etc. I am going to undo my handywork and put it back to stock specs internally (mainly power section - NFB and Presence) and externally. I swapped the original board with someone here so will have to make do with a BrianH ptp which will look good, but not quite the ST202 original early pcb, unless anyone here has a spare one?

[frank9310]

Yeah I looked at several currently on sale on ebay and they all seem to have different signal caps. Some have orange lego types while others have the mustard and orange drop looking ones.

This 1977 one here has the toggle switches but not sure what type caps. I just know that Trower's MV with the Toggle switches is his #1 amp that he used to tour with and recorded the last few albums with. The tone is absolutely killer.

No pics of caps but toggle version. The guy says he replaced the PT and it looks like a laydown. Is that what it would have had stock or would it have been a stand up PT?

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0385637087" onclick="window.open(this.href);return false;

Trower's 1997 version

http://forums.vintageamps.com/viewtopic ... er#p656608" onclick="window.open(this.href);return false;

[neikeel]

Yes those are the exact cosmetics of mine (except 4 holer).

That amp looks pretty good to me and if I were in the market for a 100mv (apart from George's kit ) I would look at that v hard - ask if he has any gut shots. I think mustards or green bean caps would be preferred.

[frank9310]

it had a couple mustards around the outsides but straight down the strip were mostly all green. Never heard of green beans. Are those similar to mustards in character?

[neikeel]

Green beans are good.

Slightly more aggressive than mustards (very similar to the yellow chicklets beloved of the 1972 amps).

[frank9310]

ah cool! Any youtube clips of green beans floating around that you know of?

Thanks!

[AmpegSVT]

Pg. 29. Does this sound right?

Solder the shield in place at the LOWER, LEFT jack terminal.
Solder the conductor in place at the LOWER, LEFT terminal, as shown.
Note that the coax is grounded only on the input jack side, to prevent
potential ground loops.

Also pg 24.

After soldering, test for resistance between the shield and
conductor with your multi-meter. There should be none.

[SDM]

Pg.29
Yeah little typo there, should read shield lower RIGHT, conductor lower LEFT as shown in pics.

Step 24
Yeah another one there. Since gain pot is only hooked up to ground on one lug, shielded wire conductor on another at that point, shield to conductor should read about zero ohms (with gain pot set to 0) to around 1 Meg (with pot cranked). If they you read around 0 ohms all the time, regardless of pot setting, the inner conductor is shorted to the shield and you need to redo shielded wire (which is the main point intended there).

I'm sure George will update those things if he hasn't already in the larger file or CD. Good eye on spotting those!

[Structo]

I was looking at the 100 watt Master Volume Kit Layout and noticed an error.

If this has been corrected or mentioned before, please excuse me and carry on.

On the preamp filter cap shown on the left side, that sits below the preamp board, it shows the two red wires labeled B to connect to each end of the 10K resistor that feeds the 100K plate resistors of V1.

The 10K resistor should be jumpered to the next 10K resistor to the right by joining the two turrets at the tube side of the board.

Again if this has been brought up before, disregard.

[VelvetGeorge]

Thanks all, new version uploaded.

Please let me know if the revised text makes more sense.

All, did anyone find steps 23 and 24 out of sequence? I had to correct the order on the file I had on my local server.

george

[SDM]

I was looking at the 100 watt Master Volume Kit Layout and noticed an error.

If this has been corrected or mentioned before, please excuse me and carry on.

On the preamp filter cap shown on the left side, that sits below the preamp board, it shows the two red wires labeled B to connect to each end of the 10K resistor that feeds the 100K plate resistors of V1.

The 10K resistor should be jumpered to the next 10K resistor to the right by joining the two turrets at the tube side of the board.

Again if this has been brought up before, disregard.

This is in the Wiki I see. Must be an earlier layout revision there as it is in the final layout and instruction layouts. Anyway to George, the R4 revision (which I probably sent as a PDF and pics) I believe was the last, has the jumper for updating that.

[white room]

I don't know if this has been mentioned elsewhere but in the parts list for the ceramic resistors the color code given for the 470 1W in the instructions shows gray-red-brown but it should be yellow-violet-brown.