This is my personal Deluxe Reverb. I just bought it from Division Street Guitars in Peekskill NY. Great shop, give them lots of business!
I added the blue jewel on the light bulb. Blue on silver is just right for me.
This post is just about general routine stuff. Amp had the rectifier tube removed and replace with a couple of 1N4007 diodes. Gross...... Well, at least not for me.
Next was just the filter caps. Sad, old and leaking. I didn't keep the sleeves this time cause, well, who cares? It's a silver panel amp! You can see they are leaking badly. Please don't leave stuff like this intact for the sake of "collectibility." Remove and replace.
I like to put two 80uf@450v caps in series with two 220k 2 watt bleeder resistors in the first filtering stage. Keeps me from getting zapped! And if you have an amp that has 500+ volts sitting there before you hit standby, this is safer. 80+80 in series is 40uf....... Perfect for a tube rectifier where you do not want to go over 50uf.
Next is the 470 ohm grid resistors. One was replaced but I just did both. You can also see those .001 capacitors from pin 5 to ground. Gone. Never needed them! The AB763 circuit is just better.
In the phase inverter I went with a .002 cap feeding it from the preamp. The silver panel amps use .01 which I don't like much and the black panel amps use .001. I like it somewhere in between. You can freely experiment with values there and see what you like.
This is my first amp with reverb since 1992! New sounds for me. Absolutely beautiful voice. I used all American and European NOS glass. So hopefully the public will get to hear this some day when Covid has passed. And it shall pass like everything else. Let's keep it real and get through these times together. God I miss live music!
Of course, these old Fender amps have a way of getting away from me. So as long as I don't sell it.....
I should add, the late 60's Fender amps with the removable baffles like this one are some of my favorites. They're consistently great sounding. I'm not a fan of the tweaks they did but those are minor and it's a piece of cake to put them back to the black panel glory. The transformers are pretty much the same, this uses a 5AR4 rectifier rather than the 5U4. That's important. The amps made soon after this are very good still, right up until the 1980's. They're all hand wired. But these late 60's amps, you have more fun options. If I wanted to I'd replace the baffle with Baltic Birch. Mojotone makes those ready to install. I've done this for clients and for a couple amps I owned that had cracked baffles. The later ones the baffle is glued in. Bah! Why???!!!
So do consider one of these if you have fancy champagne taste on, well, a good wine budget. No they ain't beer sadly, but still priced more reasonably than the vaunted black panel amps.....
Do you generally shoot for running a tube rectifier about 10µF or more under its maximum capacitance, or is it safe to run it at maximum? I think the 5AR4 maxes out at 60µF, right? Great safety tip at any rate! I bet this is runs a lot cleaner.
ReplyDeleteAnd happy new amp day!
Hi. Good question.
ReplyDeleteTruth is I'm not all that picky. The original arrangement is two 16uf caps in parallel creating 32uf total. How I set mine up is a total of 40. Truth be told, I can totally be happy with 32uf, 40 or 50....
My main goal here is safety. Unloaded some of these amps can sit at over 500 volts until you turn the standby on. Older Fender amps like the tweed Bassman or a white Bandmaster, that's almost always the case. So I'd prefer to have some headroom.
I'm not certain this one runs much cleaner than it would with 32uf. Probably splitting hairs.
Old Marshall amps I usually go with 32uf caps, or stick close to original if it's say a JTM-45.
Now on a Black or Silver Champ or Princeton I like to use those CE filter cans, the expensive ones. They're tidy. I prefer to go 40 on that first stage.
I haven't gone to 60 with a tube rectifier myself yet. I don't see much benefit personally. I mean, we like a tube rectifier for it's natural response so why go all the way to 60? I like a god bit of compression myself but don't care for hum so somewhere in between is good enough for me.
Thanks! Jef
Thank you for clearing this up. I usually don’t veer very far away from the schematic in the filter section, but I’ve had a couple of late 60s bandmasters come through recently with really high values here. One of them had two 180µF caps (schematic has 60 or 70µF in series). I don’t actually know if 90µF is pushing it for a solid state rectifier, but it got me wondering how far you should work a rectifier circuit—tube or otherwise. (I replaced the crazy high capacitors with 80s @ 400)
DeleteAnyway, I really like the idea of beefing up the voltage rating here, but didn’t want to jump in without knowing more about how much headroom there is to play with, and how much that might effect tone.
This has been really helpful. Thank you so much for taking the time to elaborate, Jef.