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Interesting. I've never had a chance to play a redwood guitar. How would you describe the tone, as compared to your other Tele's (presumably alder or ash)?

This would be a more astute assessment: BTW, my own reasons for spending lots of $ trying to get the best sounds is not because I think that someone in a club will be able to tell that I use Lollar pickups or whatever. It's so that I'm happy with my own sound, relaxed, and able to play without...

Yeah, that video again. The guy has also posted similar wisdom on amps. He's definitely not an EE either. At least he gets his videos up everywhere. Consider the simplest empirical experiment: Two guitars unplugged. Strum the strings open. Do they sound identical? If all guitars sound the...

Agreed. I still see this recommended once in a while and it doesn't make sense. Often the tubes get biased very cold. And of course tubes can drift in either direction. Best to bias in a safe zone, and if there's some perceived crossover distortion (doubtful) you'd need to live with it...

> Don't know what this cap on the bias pot does and was going to remove it to put the amp back to spec as it's > not on the schematics, thanks. Not sure which schematic you're looking at, but you need filtering on the bias supply. Were there two separate caps? Make sure that filter caps in the...

PS: There will be very little current going through the diode in that circuit. In many cases, the key spec for a rectifier will be "PIV" (peak inverse voltage), which has to be spec'd higher than max voltage at that point. But you're going from higher to lower, so the rectifier is probably...

I'm going to offer the following advice as a starting point for searching more detailed info. If you have limited experience with this, you should be able to find good instructions if you have the right key phrases for searches. Hopefully a few guidelines will help. The output tube -grids-...

Checking back to see how you did with this. I may not have a chance to check the forum much, so I wanted to make sure that things went smoothly.

Julian has worked and recorded with a friend of mine, and he has always been modest and very friendly when I've talked with him. BTW, for any Julian fans who haven't heard his work with Eric Harland, that's a treat. That was an all-star band with a unique sound.

Yeah, don't work on tube amps if you're tired. I used my simulator software to run plots for the Fender 5F6 Bassman. That's the amp that has a tone stack with similar changes to many that have been suggested here. I'll attach three images that characterize the response. I don't personally...

SFVR = Silver Face Vibrolux Reverb? If so, you've hit the Goldilocks zone for each of those ranges of amps. I've always liked the Vibrolux cause two speakers do something that a single speaker can't (and it's not incredibly heavy). There's a complex interaction between the two sound...

I was just looking at the Super 5F4 schematic. That's an interesting tone circuit. If yours is similar, I can see why you'd like its midrange.

That should not be the case, as long as you've got good 12ax7s. From Tweed->Blackface->Silverface you will see that plate voltages increased, while the amps got louder but much cleaner. It looks like the voltages across the plate resistors is still low, so perhaps you're still using higher...

Lots of work! Did you change the 12ax7 cathode resistors to 1.5k?. I may have missed that. The cathode resistor values on your original schematic will bias the 12ax7's very cold. My tweed Harvard has 302v on the plates of the 6V6's, so I think you're fine there. If you check the spec for...

Very good then. The pure capacitive divider is an interesting concept but I've never seen that used in a guitar or hifi amp. The 8 to 10 octave range would make that difficult, since there are always resistors for ground refs. The caps would need to be scaled so their reactance is a lot lower...

BTW, you could consider using separate cathode resistors for the output tubes (each with its own bypass cap). That will do a couple things, including allowing easy measurement of output tube current for each separate tube. That's where it's handy to measure cathode voltage. Divide that by the...

Glad to hear that you're making progress. I'll try to stay with this until you're happy (happier?) with the amp's sound. Re your numbers: The key figures are B+ and plate voltage. That will tell you how much voltage is dropped across the plate resistor, which will give an idea of headroom...

It looks like you're missing the concept of reactance or something. You do understand that a standalone pair of capacitors with no paralleled resistance will be very different from the circuit we're talking about, right? This circuit is very much frequency dependent. At lower frequencies...

The plate voltages will affect headroom, and they're an indicator of whether the tube is run warmer or colder. Warmer = more current = lower plate voltage cause higher current drops more voltage thru the plate resistor. Ohm's law and all that. But this shouldn't really affect the tone stack...

If I'm reading that correctly, you're only dropping 50 or 60 volts across the plate resistors? Your red ink values on the schematic look like you swapped 1.5k's in place of the previous higher value cathode resistors. Is that correct? For point of reference, the tweed Harvard 6G10 lists...

Yeah, I was actually agreeing with you, Wally. By 'that amp' I meant the linked schematic above. Badly stated on my part. BTW, I used a Bassman on stage for years. Moved 'up' to a Twin and could not get the right sound with it, even at higher volume levels. The Bassman hits a nice spot when...

I'm sure this was mentioned before, but I'd personally go with lower B+, so -more- voltage drop across the rectifier tube. If there's any concern about the filament current, you could go with a solid state replacement, like the Weber Copper Cap: https://www.tedweber.com/?s=copper+cap (I'm not...

The Spice plots were a good idea, Phrygian. Auto-scale makes the charts a bit tougher to compare, but the overall effect is pretty much what I expected. I think people often build those amps just to crank them, which would account for some of the design decisions. With the volume turned down...

I agreed with some of your other comments, but I don't see how you could consider the 100p and 220p caps coming into play at low frequencies. Even at 320hz, which is midrange, around the frequency of the high E string, the reactance of the 100p cap is about 5Megs. It will be totally swamped by...

Yeah, some people are surprised when they try to bridge the two channels of that amp. Due to the extra tube stage (and resulting phase inversion), they subtract rather than add.