Friday, April 13, 2012

Resuscitating a Peavey Valveking 212





This Valve King 212 arrived here completely defunct with a blown power tube.





This amp is one of a series of amps that Peavey, formerly doing its assembly in the US, farmed out to the Chinese. As these things go it is only a shadow of the old Peavey amps that were made in the seventies and eighties in Meridian. The cabinet's MDF fiberboard, and the amp itself is lightly built with spindly circuit boards.

It's got a major design flaw and thereby hangs a tale. The tube filament supply and the low voltage supply for the solid state devices and channel switching relays is part and parcel of the same circuit. When (not if) there are problems in the power tube end of things it's likely to affect everything else in that part of the neighborhood because they're plumbed directly into this one circuit.

And, the fuses are pigtail types soldered to the circuit board.

It's a shitty way of doing things for reasons that are now to be revealed.

When one of the power tubes in this amp erupted, before the fuse had a chance to react (I'm theorizing a bit here) the voltage and current surge took out the filament diode bridge and a bunch of other things downstream including several other diodes, a transistor, a pair of JFET switches and the main relay itself. When the amp is powered up this relay is energized and stays that way. Until it gets toasted.

So the first adventure was to restore the filament and mains voltage and get a set of functioning tubes installed-which I did, which is when I found out that the channel switching was defunct. Several hours of troubleshooting various components led me to use a bench power supply to put 12v on the relays which is how I found the bad one.

Then it was off to spending a couple hours finding a data sheet for the existing off brand relay, and then finding something that did the same thing-that's two hours of my life I'll never get back. At the same time I ordered Q101, 102 and 103, as well as a socket and a dual op amp for the reverb side.

When all these things-diodes, transistors, switches and relay were installed, then and only then could I discover that the reverb was inoperative.

After further testing this morning I discovered that D118 had been fried in the general uproar. Replacing that got the whole rig operational, bias looks good, and I hope to hell the effects switching is OK because that's plumbed into it as well with a dual transistor I don't have at the moment.

When it was all assembled, it sounded like what it is-a three hundred dollar Chinese amp, thin, nasally and uninspiring.

Best bet? Save your amp money for something more inspirational.

10 comments:

  1. Hello. Nice to be here.

    Thank you for your wise tips/insight concerning so called "budget" amps.

    I was very close to make a fatal mistake, a total error of judgement by purchasing Peavey Valveking 212 combo - the name and the price tag was very tempting. But quite soon my doubts started to grow that perhaps Peavey Valveking 212 combo wouldn't really be my thing: for my tastes the sound was too one-dimensional, irritatingly "thin, nasally and uninspiring" as you so well put it. Then I put my hope on mods: possibly some or more likely all too many mods combined would hit the sound to the right ballpark? Gradually it dawned on me: "What am I? An amp designer? Not very likely in this life! No way I'm going
    to waste who knows how much more money on something I can not be 100% sure of the outcome."

    After reading your "Resuscitating a Peavey Valveking 212" entry culminating in the "Best bet? Save your amp money for something more inspirational." line pretty much sealed my decision not to waste my money on Peavey Valveking 212 combo, no matter at how ridiculously low price I could get that brand new - shiny on the outside, rotten on the inside - showroom eye candy - a whopping 70% off the retail price.

    A quest for the sound continues.

    It's absolutely brilliant, a breath of fresh air, that there are people like you who are outspoken, clear thinking, independent of any of the retailing and marketing side of music instrument business and don't have too much extra personal emotional package i.e. owning some (not so) pricy (but eventually all too pricy) gadgets him/herself, and are therefore capable of making free, no strings attached rational and objective scrutiny of of the products covered. A person like myself needs some sense beaten to my head on a regular basis - unfortunately, I'm not a sole such a lost soul out here.

    A heartfelt thank you and all the best,
    Juha

    Ps. But yet, all of this said, I'm still partially clinging to a last thread of desperately unfounded imaginary false hope and nearly at a brink of begging you for your "permission" to buy this dud: "Please, sir... I'm getting it so cheap... But what if there was some reasonably easy, feasible miracle mod no-one has never thought off [and never will for obvious reasons] which could make a difference... On and on with these self-delusional "what ifs".

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  2. Well, I'm glad somebody reads this stuff. If you want something that is going to carry you through years of playing I would respectfully suggest acquiring a Fender amp from the 1970's perhaps a silverface Twin Reverb-hand wired, of course. It's got the tone you need, easily repairable and rugged as hell. True story: The first amp I overhauled for a friend was a Quad Reverb. It went down a flight of stairs but still played the job. You can pick up one for around $600-700 USD here and I promise you that it will get the job done for you. If you want to mess with a pedal board you can do that too.

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  3. Hello.

    Thank you for your reply and your kind suggestion for an amp.

    The Fender Twin Reverb was high on the top of my "Check This Amp Out" list, but here's the deal: the Fender Twin Reverb could be quite perfect amp for my needs (kudos for you suggesting it right away, well done!), if I hadn't this tiny, well fed metal troll whispering in my ear: "High gain, high gain..."

    Another reason not seriously considering the Fender Twin Reverb is the price tag here in Finland and within the EU market area: secondhand Fender Twin Reverbs go for 950-1100€ (app. $1100-1400 USD), a cheapest new one goes for 1450€ (app. $1700 USD). My budget is more or less 700€ (app. $800 USD).

    What I am looking for is a versatile, reliable, easy maintenance, easy repair, reasonably priced high gain amp, which could easily handle some raunchy rock 'n' roll, heavy metal, classic rock, but which would also have an appetite for smoother sounds without any of the metal clang. A nice clean channel wouldn't hurt too. And to top all of the things mentioned earlier, the sucker should be able to handle the bedroom volume levels in a relatively satisfying manner as well. Ha, ha! Mission impossible?

    On the top of my wish list, for example, I had Blackstar HT-Studio 20 head, Blackstar HT-Club 40 Venue combo, Peavey 6505 head, Peavey 6505+ 112 combo, Bugera 6262 head, Bugera 6262-212 combo. All of them ought satisfy my metal troll's needs. And a few non-high gain amps: Vox AC30 C2 combo and Vox AC30 CC2 Top Boost combo. All made in Asia, I reckon.

    But after discovering your blog and reading about the build quality, maintenance and repairing issues caused by the budget amps, you put some healthy dose of scepticism and caution into my mind. Now my wish list seems to be blown to pieces. Seems like all of my choices are mildly put a bit iffy when considering the build quality, maintenance, repair and longevity issues.

    So? What to do? Get the metal troll off my back? Get a new glorious hobby like jogging or something? Far more cheaper and healthier option than playing an electric guitar, or more precisely, trying to figure out what kind of gear to have.

    All the best,
    Juha

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  4. High gain is overrated in my opinion, a pedal will get the thrash thing done pretty well. My taste runs to people like Freddie King and Albert Collins.

    I think the key here is 1) get an amp that has published service information out there. That rules out Blackstar and Bugera, and the AC30C2. There is service information available for the older AC30CC2. Neither AC30 variant is particularly high gain either. They also have problems with ghost noting. But if you want to pretend you're one of those guys at the Cavern....can't remember their names....they have the look.

    A workable alternative may be one of the Fender Deville series amps. They're particularly nice if you can pick one up with 2 12 inch speakers. They have a few well known quirks but they're easy to get serviced and the info is out there. They have a good clean channel and a drive channel which is OK. If you're playing at home and annoying the reindeer occasionally these may be a little much, but the Blues Deluxe is a similar production with a single 12.

    I don't know how many tube amp mechanics there are in Finland, I guess not too many. There are a couple guys I've heard about in Sweden but that's probably a long ride, especially in winter. So you want to have something that will run for long periods of time but can be repaired locally.

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  5. Hello.

    "...a pedal will get the thrash thing done pretty well."
    H'm... A pedal. A good point, but don't tell it to people who take their metal a way too seriously. My preference sound is raunchy rock 'n' roll with a touch of metal flavour. When I play something from the top of my head it quite often evolves into some sort of metal-blues riff based improvisation. Somehow it just feels right. It comes to me quite naturally.

    I'd like to be able to cover a wide range of sonic spectrum and when it's time to hit the pedal to the metal, I want my gear to deliver the goods. Maybe too much asked for a single amp?

    I don't want to copy anybody's sound per se. That's one of reasons I got myself a guitar exclusively designed for metal: Epiphone Dot which I modded to match a stock Gibson ES-335's electronics and pickups. Ha, ha! Now that's metal! I guess that makes me an ordinary Albert "Metal Butcher" Collins!

    "...get an amp that has published service information out there."
    Definitely. I'll make that one of my most crucial guide lines.

    "That rules out Blackstar and Bugera, and the AC30C2."
    No surprises here as I had already read the sad story of 'Blackstar HT40 Service Review'. Ruling Blackstar out really saddens me. It seemed to be a fairly promising all-arounder and within my budget. If I didn't want to be the next Kerry King, I could have dialed some other tones out of it.

    "AC30... They also have problems with ghost noting."
    Fortunately I mentioned Vox AC30s. Once again you provided me some useful information. Well, another amp ruled out.

    "I don't know how many tube amp mechanics there are in Finland, I guess not too many."
    There are tube amp technicians in Finland, no problem, especially ones who are naturally most experienced to fix big sellers and classy vintage brands.

    "So you want to have something that will run for long periods of time but can be repaired locally."
    Precisely.

    What becomes to these newcomers Blackstar, Bugera... I have my doubts. I'll have to find out before I make any fatal decesions. Some lone electric wizard living in a place with no name just isn't enough, when we are talking about reliability and longevity in terms of service and maintenance.

    But isn't it so that demand creates supply? If so, then logically there will be suitable repairing services available in the long run, if a brand lasts long enough on the market. But how long time I'm willing to wait for reliable services to pop up? Not a minute. Not even a three year guarantee would provide me enough security to count on that maybe one day there will be sufficient repairing services available. I want to know right now, if there are enough stores/technicians capable of repairing the gear I have.

    Most of the pondering above is highly speculative, since I have already ruled Blackstar and Bugera out. Only the first word in the first paragraph is spot on and viable.

    "If you're playing at home and annoying the reindeer occasionally..."
    Ha! Right! And some polar bears and an occasional unexplained pink elephant. On more serious note, the whole idea was to save some money. I already

    have a sort of practice amp. A sorry Squier 15W, an individual which is a total disaster I got for free. Maybe I'll get a real practice amp eventually.

    So what's left? Peavey 6505, Peavey 6505+ 122, Fender Twin Reverb and Fender Deville. Right now Peaveys are my first choices, but if turns out they are one-trick metal ponies, I'll have to consider ordering a secondhand Fender from the USA.

    Or go back to the drawing board and re-evaluate the whole thing all over again.

    Thank you for your valuable advice,
    Juha

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  6. Free means you don't have to pay. It's a good thing that you have some competent amp mechanics in your corner of the world. If your choice is a Peavey, make sure that it is an American made amp-they're more robust, and also make sure you troll the net for opinions and serviceability issues. I like the Classic 30 and their kindred-they sound good but serviceability is a pain in the butt. I do think a Deville or Blues deluxe would be a pretty good choice. They're like the Volkswagen Beetle of tube amps. Fender has made millions of them, there are no secrets, every problem people have had is well documented and they sound pretty good. I like the Devilles with 2 12 inch speakers but you may like the 4x10 configuration as they are a little more brash and in your face. I would definitely try and buy one locally even if you have to pay more, that way you're not going to inherit problems from some person. For really dark metal tones, you will have to spend a lot of cash though. I like Orange amps myself but they're pretty pricey. I avoid Mesa Boogies like the plague. Best of luck on your quest, and let me know what you're thinking of if a deal is looking close for you.

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  7. Oh the joys! I came across this blog when asked if I could fix one of these for someone who wants it tomorrow. He's going to go out and buy some new output tubes and has been told by several people that they don't need biasing. This could prove interesting!
    As for him getting it by tomorrow night,.. I have a feeling he'd better run round all his mates and borrow something a wee bit more up to the task of gigging all night.
    Interesting that Peavey seem to expect us to have a crystal ball handy cos there is not one single voltage reference on their schematics. I'm clean out of crystal balls and rocking horse shyte to as it happens, my last bucket of that went years ago!

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  8. Glad to see somebody reads these dark mutterings. I was not real impressed with this amp. When all was said and done it just did not sound inspirational. I'm all about clean tone and this amp just didn't produce a desirable clean tone. On the other hand you can get service information from the House of Hartley Peavey and order parts from any good electronics stockist which is a good thing and I do not think there are too many SMDs inside it. Here in the states many of my friends in the trade use Mouser, Digi-Key, Allied, or Newark Electronics for parts. It was a real pain in the ass (arse?)putting new fuses on the board because they're pigtail fuses. I had to take ordinary fuses and solder leads onto them for this purpose.

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  9. I am seeing a similar issue with one. Do you happen to have the part numbers for three replacements that you sourced?

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  10. I didn't keep a detailed list but everything is on the schematic or the parts list. There is a website for the cheap assed Sunhold relays and they're directly replaceable with better quality stuff from Mouser or Digikey. The Peavey service people are still pretty helpful so I think a call to them would suffice.

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