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Ended up buying a 12" Celestion greenback, and a 12" Celestion G12H, will have both inside one 2x12 cabinet, and the Palomino driving them as a 'head'.
I resolved to making the speaker cab stereo/mono capable. The wiring requires two Mono 1/4" jacks coming out of the speaker cabinet, and a DPDT switch that lets you switch between 2x12" in parallel to one jack (4 ohm), or two independent 1x12" channels, one to each jack (8 ohm each).
This way, I can use a Mono configuration to drive both speakers together, or I can switch to Stereo configuration and split it up, to drive each speaker independently per jack (in which case I would connect the head to the specific L or R channel depending on which speaker I want to use...
Boy am I glad I came back to this thread. Thanks for the continued input, Verne!
Congratulations on picking up another! I was on the lookout for ya but didn't see too many MIAs...
I appreciate the thought and thanks. There don't seem to be many of these around anymore - either on eBay or CL. Frankly if they made 500 total I'd be surprised. I tried a couple sellers on CL and finally found one who would ship, but only after there was no interest from his local community. It's mint and I got it for $100 plus $35 shipping. The second one does sound much better than how my first sounded before the mods so there does appear to be some variance from one to the next.
Originally Posted by gnolivos
Verne: I still think that switching from Stereo to Mono (i.e., from 4ohm to 8 ohm) via a switch while the amp is ON is *not* a safe thing to do. Comments?
It comes down to understanding what's going on in the circuit. The output section runs through an output transformer so what goes to the speaker is somewhat isolated from what's going on inside the amp. The danger comes in putting an incorrect load on the transformer for a period of time. In most cases this will cause the transformer to overheat which usually causes the transformer windings to melt and short before any damage happens to the circuitry driving it. As long as you're just changing things by flipping a switch I don't see how you can cause any damage - unless the switch shorts. But if you are nervous, simply turn the amp off, make your change and turn the amp back on again. Bear in mind it gets pretty hard on the tube since you are causing them to heat/cool/heat.
I'm certainly WANTING to do the mods. I think if you could find the time to consolidate them in one 'post' that would be awesome. I think I have a good idea of what to do, but it took a good while to read through!
Would you be able to provide us with correct procedure to drain the capacitors in this amp? I already have built a wire with 10Kohm @ 5W ceramic resistor. One side needs to be clamped to ground (chassis), but for THIS AMP, what is the recommended point to drain the caps? You cannot really reach under the caps on the V8 without removing the board, so I am trying to find a good spot that you can reach on the TOP of the circuit, to tap into. Some people seem to even prefer downstream after the resistors etc....
I'm going to assume V1 is one of the tube sockets... at Pin #1. But which tube?
Also, do you normally remove the tube to get to PIN1, or do you make contact at the base of the socket on the other side... I think you can access them through there, not 100% sure.
And yes, I did look at the schematic!
I hope you don't take me for a jerk for what I'm about to post, but it needs to be said, so bear with me.
This is one of the main reasons why it's difficult discussing this stuff on an internet forum. Particularly with the V8, we're dealing with dangerous voltage levels that need to be treated extremely seriously.
What I posted above makes perfect sense to anybody who has a rudimentary understanding of what they are doing. Your question indicates this does not include you. No disrespect meant.
At this point I would ask you to find a tech in your area who can explain these things to you and show you the proper procedure for draining capacitors - something that goes beyond where to connect wires. It involves what to wear, how to stand, what to do and what not to do.
If I go any further I run the risk of a major misunderstanding, which could lead to you being physically harmed, which I do not want and do not want to be held responsible for.
Please understand I'm not being a jerk, just watching out for your and my well-being.