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I'm Email to Customer Peavey but not answer
anyone have schematic please send to me
anyone have schematic please send to me
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Give them time.
The PV Bravo really is a cool little amp.Education is what you're left with after you have forgotten what you have learned. -
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PV Bravo
There are a few errors in the schematic, FYI, which I have found while pulling mine apart...it is a great circuit though! Add a good speaker cab and some JJ EL84s / EI 12AX7s and its is a pedal less gain machine! Also the schematic is a little poorly organized and more confusing (to me at least!) than is necessary..Comment
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Hi ted, welcome to the forum.
Well, if there are errors, why don;t you tell us what they are?
I don;t like schematics that way either, but PV draws maany of them that way, so if you look at the 5150, Rockmaster, or various others, they are laid out the same and I am familiar with them and have no trouble anymore.Education is what you're left with after you have forgotten what you have learned.Comment
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I'll review my notes and correct the schematic, although some of them may relate to variation between production versions (although I don't think the Bravo was popular enough to be in production too long
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I have run across the designers explanation of the "poor mans noise gate" dual diode coring circuit between stages and he maintains its only active in the clean channel although people swear jumpering them makes the amp sound 1,000% better; whats your view Enzo?Comment
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Me personally I'd rather have a list than having to scour the two schematics looking for changes.
I mean if you are talking about things like a 390 ohm resistor in place of the 400 ohm resistor between plate and screen B+ nodes, that is just parts availability. Peavey uses the 400 ohm resistor there in most of their amps, and freely use either one in production. That's not an error.
The noise reduction is only on in the dirt channel, NOT the clean channel. Its purpose is to remove low level noise, like hiss, which is only an issue on the high gain channel. It chops out a little portion of the waveform at zero crossing. Thios might be fairly noticable in clean, but pretty much disappears into the distortion of the dirt channel. The clean channel signal path does not pass through the tube stages it is between.
In later amps that used it, they added a 1Meg in parallel to the diodes to provide a better DC path for C1.
I think most things people decide to do make their amps sound 1000% better... to them. If you want to try it, simply tack a wire across the diode pair, shorting them. it might sound a little different, and I'd expect the noise to increase. If you don't find it an improvement, cut the jumper wire. If you like it, leave it there.
I'd put it in perspective. 1000% better? More improvement than a different speaker? Better than different preamp tubes? Better than fresh power tubes? Better than actual changes to the tone stack? etc etc etc. I have to say I'd be awfully surprised if I found a "night and day" difference.Education is what you're left with after you have forgotten what you have learned.Comment
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Mod myopia is a phenomenon related to the time between the A->B comparison and is related to the effort required; swapping all the caps for polystyrene is such a PITA and takes so long you've completely forgotten how your amp sounded and are missing it so much you'll swear you hear Gabriel's trumpet once its back together.Originally posted by Enzo View Post
I am interested in the cathode bypass caps/attenuating series resistors PV has used on the Bravo and VTM amps; giving selective boost.
I'll give a (meaningful) bravo correction list when I get the time...Peace!Comment
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As to PV Bravo Schematic/layout
the errors I found are in the board layout figure, with component values and placements on the PCB, so I think the schematic is largely correct (except for unclear wiring to the preamp tube board)
C19 mislabeled as C9 in layout
C11 = 0.47uF/20, listed as 0.047uF/450v in layout
R5 = 680k, listed as 68k in layout
R46 = 47k (as R51), listed as 470k in layout
J108 -> J106 and J109-> J107, not as in schematicComment
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Bravo Mid tone control swap
Hey,
I find the Bravo (just picked one up the other day) kinda muddy without the bright on. I goofed with it for a bit and found most of it was in the clean mid. The mids just go from almost non-existent to muddy at about 3.5/4. Gain channel is fantastic, no complaints. So, any suggestions as to replacing the tone pot, as in, with which brand, etc.? Also, I find the fan kind of loud and was wondering if anyone else has thought of reploacing or outright replaced it. Model suggestions anyone? Lastly, looking at it from the back, are V1 V2 V3 left to right or right to left? Changes I made are: new 12ax7s and a Weber 1230-55. I'm not too interested in doing lots of mods, I think I'd be happy with just a better mid tone control. Playing a 1980 Ibanez AS200 through this, as well as through a mildly modded (tubes, speaker) C30.
Thanks for any suggestions.Comment
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looking in the back the tubes are right to left V1->V2->V3->el84->el84Originally posted by rivertramp View Post
one of the best mods is tossing the original el84's
JJs make it sound a TON better (as does a decent speaker)
Tone pot only needs replacement if its noisy; you think its hurting the mids? If its the clean channel mid, its a 50k CTS linear pot BUT its a framed pot and a lot of soldering is required which can screw things up unless you are skilled at this.
I think the Peavey part # is 71190511; they will know (and sell you) the exact part if you call them. Its probably fine, the design hurts the mids.
The Bravo is a major "scooped mids" amp; a suggested mod to get better mids on the (identical circuit Rockmaster preamp) is as follows:
"1. The Mid control on the clean channel EQ doesn't really work so well. As you turn it clockwise it adds more mid-bass, but keeps an overall scooped response. This is caused by a capacitor across the Mid potentiometer. Peavey used a .015uF cap (C9) there. You could simply remove it, but that will result in the mid pot turning into more of a gain control considering its 50k ohm value. Instead, I recommend replacing C9 with a smaller value, between .003uF to .005uF."
(from a HC review)
C9= C20 (Bravo)
Mouser 505-FKP24700/63/5 might work ($0.47)
another RM user was also unhappy with the mid response:
" If you want to change the tone of the amp check out the coupling cap between the gain stages(C14 / .0010uF on rockmaster unsure on the Ultra) feeding the third tube stage (V2a). It has a frequecy rolloff of 340hz, which means it notches out everything below 340hz. Try a .0022uF in its place, this should give you a rolloff of about 154hz letting more low mid bass through. This made a huge difference in my rockmaster. Also look at the bypass cap on V2a (C17/.47uF on RM). It creates a pass frequecy of 450hz. Everything below 450hz is cut. Try using a 1.0uF which will give you around 205hz. These two mods really took the honk out of the rockmaster, gave it a great boost in the low mids (mesa land) and for less than $10 dollars in parts and less than an hour of work it was well worth it."
(from a HC review)
C14 = C2 Bravo (Mouser 1431-6222K $0.33)
C17 = C11 Bravo (Mouser 667-ECQ-V1H105JL $0.46)
The first mod (C20) changes only the clean channel and is pretty safe, the other changes Clean and Crunch/Ultra and its not 100% sure it will sound better on the Bravo (probably will).
Oh the fan! Yes its loud, its a 40 x 40mm x 10mm 24vdc unit and its spinning fast,
this might work for $1.75 and be 15-20 dB
http://www.allelectronics.com/make-a...ING-FAN/1.html
you'll need to splice the original connector on (solder + heat shrink) iff its quieter!
Mouser will charge $15 (664-AD0424MB-G70LF)Last edited by tedmich; 08-15-2009, 02:25 AM.Comment
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Bravo Reply
Tedmich,
Wow, thanks for the quick reply, that's great.
So, as I'm kind of new at modding stuff, let me get this straight. If I want a bit "brighter", I guess, response form my mids, change the capacitor to a .003 - .005, correct? I'm assuming C9 = C20 means I would be replacing the C20 cap in the Bravo. That's great, don't want to do a whole pot if all I have to do is the cap. Now, I don't know how to discharge the voltage. Is there a way you can describe to me or send me to a site/page that would steer me through that part? I'm not keen on electrocution. Already replaced the el84s with JJs. (A side question - the JJs I put in were rated at 4.85/21.00. I also noticed in the store others rated at 4.95. Will these higher rated ones give me more clean headroom, or do they break up earlier?) The Weber 1230-55 sounds nice in there, but part of the reason I'd like clearer mids is it handles that lower range handily already.
Thanks as well for the tip on the fan, I'll order one soon.
Best, rtComment
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here's a primer on amp safety, bleeding filter caps etc.Originally posted by rivertramp View Post
Tube amp building and use safety
I have to say I am unsure what you mean by " the JJs I put in were rated at 4.85/21.00" is this a matching parameter?
the C20 cap is (I think) a little green ceramic (I have replaced mine with film a while ago!) and you will use a 0.0047 (about 1/3 the original value) this isn't set in stone, but you can always "piggy back" another one on there to get higher values.
To get to the soldered leads, you'll have to remove the whole board and wires too, the solder is on the opposite side from the component.
You MUST take detailed well lit digital photos before starting to assure you get it back together correctly! Measure three times, cut once etc. etc.
Some remove solder with a "solder wick" a woven wire which sucks up the molten solder, others prefer a bulb/pump to vac up the solder. Use a very small solder iron, a Weller Marksman Mini Iron (12 Watt) SP12 is about ~$15. (A 40w RadioShack special may cook the board) Practice a bit first!Comment
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Bravo 112 mods
tedmich,
Thanks again for the quick reply.
After looking at this stuff, I think I'm going to order the fan, find a cap and just get my amp tech to do it, he's pretty reasonable with his rates. I don't have a digital camera, so that doesn't help. I don't mind doing small things, but taking things apart like that, I'm a bit wary. I know myself too well. Thanks as well for the great link on tube amps. I will let you know how the mod turns out. And I have to add, for just coming across this site, it's been the most responsive of any I've come across.
As for the JJ ratings, yeah it may have just been a matching parameter, I'll ask the next time I'm down at that music store.Comment
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could really use a PV Bravo 112 schematics pdf.
Hey there,
I have one and would like to fix the reverb, I get return but no send. I traded out tanks...same.
would appreciate it. I use this amp instead of a 70's twin reverb when I play smaller clubs. I love it... I put one of the celestion classic 30s in it and another in a cabinet, they sound great and it stands a little taller for shallow stages
Hey, know where i can get a cheap output transformer for my Music Man HD-212? It's the bigger of the two choices, can't remember what I did with the numbers. I'm sure one of you geniuses could figure it out, let me be your student.Comment
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