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Old 21st September 2012, 12:30 PM   #11
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Join Date: May 2010
Location: was Chicago IL, now Long Beach CA
LOL in my enthusiasm I must come off as a dumb kid about to rip into it. Don't worry, I'm being careful and moving slowly, looking twice and asking first. Bought a good fan today, same kind of shaded-pole 120vAC motor, about the same but a better ( rated quieter, sufficient output) brand. A lot of quiet fans use shorter-life bearings and insist on vertical mounting, and the very quietest are low-voltage DC computer fans sometimes run from pulses. For now I'll leave the same type fan, same series resistor, might add some speed control later.

Enzo, thanks! I had no clue they already used DC heaters!!!! I must be blind, V1A pin 4 to ground, 9 the common for two heaters in V1 not connected, V1B pin 5 to V2A pin 4, 9 common in V2 not connected, V2B pin 5 to 27V- thank you for making me look again! I'm impressed, by Peavey & you! Well, that's one thing less to think about doing.

I still think Peavey's white papers are self-serving doc of a misguided mission, at least so far. Nice to see what he's thinking though, and sharing his extensive experience. But IMHO he's promoting urban legend about transformer saturation being part of tube amp charm. I've been hearing that claim for years, but I've never liked the sound. Then again, I never liked my Marshall.

I understand what the zeners are there for, and if I was selling these to rockers I'd put them in too. I might be grateful it I ever do something stupid. I see other tube preamp / opamp reverb combinations without them or with a resistor to soften the knee, but I doubt the zeners ever even come into play in my use, so they probably do no harm if they do nothing in my use. Peavey makes these amps to withstand 1000 times the level I drive into it with no pedals and no powered pickups. I've got a lot of reasearch and measurement before I do anything to the reverb circuit. Right now I know it's never over-driven or I would hear the spring, but I doubt the zeners are limiting yet. But I don't even know whether I want to increase the drive or increase the sensitivity of the recovery amp section. I never hear the sound of springs over-driven. I suspect that what I will try first is just adding a 'reverb drive' knob so I can adjust a good signal level to the spring despite the wide variation of the level from the first tube stages. Like when I use my Peavey valverb, I can adjust the input and output levels; my favorite Fenders didn't have it but seperate controls for reverb drive and post-reverb mix are really practical and useful if you play a wide range of input levels and volumes, especially when I'm going for clean/quiet/dynamic-range. But just changing to a long-decay model tank, whether short or long delay or short or long physically, might help make the reverb sound more prominent just by the persistence of the reverberation effect. Then again, I have an all-tube Peavey Valverb in the garage, and it sounds a hell of a lot better, and I love the tone control on the reverberation sound. But even my old all-transistor Tapco reverb could sound OK when I upgraded the reverb tank, and the EQ controls for the reverberation again made a big difference. So I don't see any reason I can't get the classic 50 reverb to work a lot better with a drive level control and maybe adding a primitive tone-control high-cut pot too. In an ideal world I'd have some control of compression/expansion before the reverb drive.

There seems to be stong consensus that the "dirty" mode has too much treble and too little bass, and that the reberb sounds "weak". If that's the worst problems, that should be easy to address. I think those are both side-effects of the amp being designed to handle being over-driven with much stronger inputs.

This weekend I'll try it with 2 el-84's to get an idea what the half-power switch will sound like.

BTW this amp's volume is fine. I want it to handle an exceptionally wide range of volumes and clean/dirty sounds, and I still might add some kind of power-soak.

I would like to work on getting the background noise level quieter. I haven't really tested with a shorted input, to hear just the amp. I would be interested in just trying an alternate new set of tubes for comparison.

Yes, I could glue a knob onto the broken shaft, I could spray out the pots; but IMHO good pots are really important to the whole feel of an amp, and I am really spoiled from the quality of the controls in the Alembic. Good sliders on a quality board and the Alembic preamp have made me pretty intolerant of teensie pots with their scratchy noises during adjustment.

It makes some random relativley quiet popping and fizzy noises. There's quite a power turn-off "POP" even if it's already in standby.
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Old 21st September 2012, 11:08 PM   #12
Enzo is offline Enzo  United States
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Of course it is your project. There is an old trick on Fender amps. Most old Fenders had a Normal channel - plain - and a Vibrato channel with reverb. The reverb return cable plugged into the reverb recovery jack on the rear. You could Plug the reverb return cable into the unused Normal input on the front, and now that channel's controls act as reverb controls. SOunds versatile. But mostly we wind up just setting it and leaving it alone. Same in my experience with adding "Dwell" controls to reverb drive. It seems like it would be oh so useful, and then a month later we realize we just turn it all the way up and leave it.

Pots are pots, and if you like different ones, go for it. I will say that when these little pots are scratchy, it is not from size, it is from dirt, or the occasional loose DC voltage. And if you are used to sliders, well good luck putting sliders into this Peavey. I have always found that sliders are far more likely to go noisy from contaminants than are rotary pots. As to broken ones, Peavey has all of them in stock, not expensive at all, and the parts department at Peavey will gladly sell them to anyone. Parts orders must be CALLED in, no email orders.
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Old 22nd September 2012, 01:25 AM   #13
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I've been biting my tongue, as your enthusiasm is obvious. But when you say, "I never liked my Marshall"....

Despite the tweed covering, the Classic series do sound like Marshalls. And to make things worse, they were voiced when EVH was hanging around. The more you say about what you want, the more I think the Peavey will be fighting you every step of the way.

Look, for the price of the transformers, you could buy a slightly broken Fender and have a much better platform to modify.
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Old 22nd September 2012, 06:19 AM   #14
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Indeed, if I stop contracting and get a "regular" permanent job with some security I'll probably start looking at old Fenders with 2 JBL 12's and a nice reverb, or possibly building one. Unless I need a bass amp by then. Meanwhile, this might grow on me. There was more about the Marshall I didn't like; for instance those Greenback speakers and the huge cabinets were SO efficient but rearely pleasant, kind of honking sound. Then again, when I was a teen I never really liked my strat; I didn't like the pickup positioning and how their magnetic fields affected the strings, the bolt-on neck, the cheap way everything mounted on the pickguard, the crummy screws the vibrato mounted on. Yet plenty of great music came from the same honking guitar, often with the same honking amp, which never sounded good with me playing them. I really like an SVT for guitar or bass, though I'd like to add reverb; I'd love to just pick up a VR some day.

Anyway, I finally got a guitar today, so I don't have to use just a bass. I had to sell all my Travis Bean guitars and basses when money got tight between contracts; that money allowed me to keep the house. But I bought a MusicYo-era Kramer with an OK flame top and floyd-rose for really cheap from the Goodwill auction site for really cheap. 'course these offshore ones were pretty cheap to start with, long after the US shutown and before Gibson picked 'em up, I think list was about $260 when new. UPS left if on somebodys lawn 10 blocks away, at 2111 instead of 2911. UPS knew where it was, but hadn't picked it up, so when they told me I ran over & got it. Anyway, this little Peavey is a lot easier to live with than the big Marshall. And it CAN sound similar to how I wanted the Marshall to sound.

Last edited by cyclecamper; 22nd September 2012 at 06:21 AM.
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Old 23rd September 2012, 09:24 AM   #15
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I still keep looking at those Mercury magnetics transformers. Am I just mesmerized BECAUSE they're so expensive? I can't possibly justify the price of the upgrade power transformer. But as a joke I'd mentioned that a second Peavey power transformer would cost one heck of a lot less and do just as much to stiffen the supply and much more to isolate the power amp section from the preamp section. I know this is not a hi-fi, but this isn't a totally crazy idea. I'm going to price one.
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Old 23rd September 2012, 12:47 PM   #16
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I've got nothing for you but more generic warnings about messing with one of James Brown's designs. There's only one way to find out, and it's really about what you like.

I love the Classic 50. I heard Seymour Duncan play through one, and he totally nailed those "Blow by Blow" tones with his TeleGib. I'd own one, but they're big and heavy, and I'm at that age where I'm getting smaller every year, so I got the Classic 30, instead.
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Old 24th September 2012, 04:32 PM   #17
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I ordered the missing chicken-head knobs (but in various '50's colors). It's really difficult to read the labels on the chrome background; it works worse than it looks. At the very least it needs a panel light, like a shaded LED at each knob label. Making groups different colors should help (maybe dark red for the 'hot-dirty' channel, off-white for the clean, '50's turquoise pastel for the 3 tone controls, bright white for the master, black for the presence).

I also ordered a handful of Solen .047 coupling capacitors.

I still need to put together the order for Peavey. Pots and tweed twill-patterned Tolex. I actually considered going with various non-tweed/twill patterened vinyls, but the speaker cabinet looks good and the head will look best if it matches.

A friend gave me a free Acutronics long-decay full-size tank. Actually I think it might have come out of the old Tapco reverb when I upgraded the tanks. But I think the input impedance is twice the stock value, like stock is and "E" 800 ohm but this is an "F" 1925 ohm.
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Old 24th September 2012, 04:54 PM   #18
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The reverb tanks are surprisingly cheap, so I'll probably just order the right one.

BTW I have seen some threads where people blew the op-amp and had to replace it. So indeed those zeners get called to action at least sometimes (though they obviously don't always do their job either). I've gotten a lot of advice suggesting favorite op-amp upgrades, but quite honestly at the low stock levels of reverb the signal to noise seems OK because when the signal mixed in is this low any noise is inaudible or masked.

As I play with this more, the reverb isn't really all that weak unless you have "Pipeline" and "Wipeout" in your set list. It's more the operational procedure I'm used to; turning the knob way up to hear the reberb, then setting the actual level to use. Kind of like "what's that soudn like when I'm this dirty" "oh yeah" "OK I'll take about this much of that". Especially using reverbs with their own tone control, I want to be able to hear it all-wet. But the range of the mix pot is really a pretty usable range. Same with the tone controls; the controls are really somewhat more subtle than I'm used to, but their range is very usable. But again, in practical operation in a noisy environment I turn up & down to hear the extremes and listen to the band and how it affects a strum and pick before I make my selection. For the reverb, if I had a little "solo pre-fader listen' button to hear just the reverb full-wet I probably wouldn't need more range on the knob.
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Old 24th September 2012, 05:12 PM   #19
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I never did undersand why people get so attached to Marshall's gold-capped knobs; they seemed the most impractrical to me.
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Old 25th September 2012, 06:39 PM   #20
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Quote:
Originally Posted by cyclecamper View Post
As I play with this more, the reverb isn't really all that weak unless you have "Pipeline" and "Wipeout" in your set list.


Quote:
Originally Posted by cyclecamper View Post
Same with the tone controls; the controls are really somewhat more subtle than I'm used to, but their range is very usable.
There's that Marshall influence I mentioned.

Quote:
Originally Posted by cyclecamper View Post
I never did undersand why people get so attached to Marshall's gold-capped knobs; they seemed the most impractrical to me.
I think Jim was going for the then-current high-end hifi look, like H.H. Scott.

Chickenheads are a lot more practical for guitar players. Or fluted "RCA" knobs with the big white line.
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