West Grande mod

[flintrock]

Recapping a West Grande, also rewiring the power switch. I'd like to use the polarity switch as the new main power switch. Maybe use the existing power switch as the standby switch. Looks a bit tricky, anyone happen to have a schematic for it? It seems to be nonexistent.

[Stevem]

You can only use the standby switch as a combo on off and standby if the original on/ off switch in not break both legs of the ac power to the PT.

[randalp3000]

Bummer, looks like they didn't renew their domain name. All the schematics used to be on the website. I did find a facebook page https://www.facebook.com/WestAmps. I bet if you message them they will send you a schematic.

Being a Michigander I would love to find one of these amps, if
you run across more please let me know.

Not sure this is much help but I have a schem in this thread https://tubeamparchive.com/viewtopic.ph ... highlight=

[gui_tarzan]

What was the domain name?

[randalp3000]

westlaboratories.com

[gui_tarzan]

I have the schematics from their old website. Here are the Grande schems.

I also have an archive of the entire website if you need more info.

[gui_tarzan]

Recapping a West Grande, also rewiring the power switch. I'd like to use the polarity switch as the new main power switch. Maybe use the existing power switch as the standby switch. Looks a bit tricky, anyone happen to have a schematic for it? It seems to be nonexistent.

Why do you want to change the switches?

[flintrock]

Thank gui_tarzan! I have tried to contact Mr. West but no reply. Being from the town these originated in (Flint, Mi.) I have done a great deal of research on these amps. Some had suggested using the polarity switch for this purpose of the main power because they believe the original switch wasn't up to the task. It does look fine, with minimal use I'm sure since this head is in fantastic shape. I installed a grounded cord, so either way I need to use the poarity switch for another purpose or disable it and the .05 cap.

[flintrock]

Another reason I wanted the schem was to know what the phase inverter tube was suppossed to be and now I know its a 12at7.

[flintrock]

This one has 100k's across the 320uf caps, should that be a concern?

[tele_player]

No problem, and presumably, this amp worked for years - correct?

I just read a note from Illinois Capacitor on how to approximate a value for these balancing resistors; their formula suggests an even lower resistance, about 31k. The theory is that the current through the resistors should be about 10x the leakage current of the caps, to ensure that the max voltage of the caps isn't exceeded.

The formula for an approximation:
R=10/C

Which is interesting, since it assumes a relationship between capacitance value and leakage.

[Masco]

I have a West Filmore. Don't dig the power/stby switching either, nor the output Z switch. Mine still needs to be sorted out, it appears that it had bias failure by looks of the burn marks. What a beast, by far the heaviest amp I own.

[gui_tarzan]

Do you need a schematic for it? I can post it when I get home later.

[Masco]

It looks very similar to the Grande, but 4x 6550 -200W monster. Very simple layout to trace, I can practically see the schematic when I look at it. Thanks.

[flintrock]

I ran the hot in to the polarity switch with the fuse in line. Removed the neutral and attached to old connecting point where the fuse previously tied in at the existing power switch and is also where the other primary lead to the power transformer connects. Power out to the rectifier also ties in on this switch. The .05 cap was removed and cord is now grounded. I haven't flipped it on yet, but sounds ok to me? I have to still pick up a 12at7 for the phase inverter today, I plan on starting it up on the limiter w/o power tubes first.