Barn Find

[silverfox]

I was at a garage sale over the week end and there it was, finally, I find one of those possible great deals. A Peavey Road Master Vintage Tube Series. 160 Watts.

So they tell me it works and all it needs is tubes. Hmm. Since I only purchase used amps on a parts basis anymore, after turning it on to verify that the tubes light- They do. I take it home for $50.00.

I get it home and of course it doesn't work as stated and start pulling it apart and performing some basic tests. If I hadn't spent the "1 days, 22 hours and 34 minutes" here as I have, no telling how long it could have taken to figure out what was wrong. as suggested first checked high voltage in "Stand By"; Oh boy, is the power tranny shot? No HV. Found the schematic on line and started tracing things out.

Actually they were right. It did need one of those skinny little tubes, a "1.5A" which I just happened to have on hand. Having replaced that I got the green status light to illuminate- indicating HV on the Screens and away she goes. Classic 80's-Pevey-Buzzing-Distortion. Which I'm not particular to so I'm just using the "Power Amp In" and driving the (6) 6L6GC power tubes at about 2 watts, sometimes.

I'm trying to decide if I'll keep it as I don't really need all this power and I've got a Magnavox stereo amp to rebuild and use as my power amp, (kinda cool para-phase power amp)

Sch attached- I had to recapture the file as it couldn't be uploaded to my file site and it was too large to attach. It is available on the Web but not easily linked to. If you have another link please post it since there is a second page with PCB layouts and may come in handy for others.

What can I, should I do to get rid of that buzzing distortion and get some kind of Marshall grind instead out of the preamp? Is this a keeper?

The inrush resistor has overheated the PCB and all I have is a 360 Ohm 10 Watt; Will the difference in ohms cause any problems? Don't think so.

Any potential Mods greatly appreciated.

Silverfox.

[eleventeen]

Price was definitely right. Was thinking you had a 1.5 A fuse in a 6 qty 6L6 amp?? No way.

My suggestion: Let it sit. It will patiently await whatever you want to do with it.

Is this a head, or a 2 x 12 combo? I can't move such tonnage around any more, nor do I need the horsepower. 1/3rd that much does me just fine.

[TIMBO]

Good score, I think at that price and all is working well, to stow it away for a rainy day is a good idea. I'm sure you'll find a good use for it. 

[SILVERGUN]

Hey SF, Willabe pointed out to me that this has the post phase inverter cathode follower driver configuration that I've been looking into recently...

In my case it was AC coupled to the output tubes (in this case DC),,,BUT, what I've found is that you can get a great clean sound with it, but the OD signal just doesn't sound very good IMO

So, maybe not a great candidate for the Marshall grind,,,,but definitely a good choice for some crystal cleans with lots of punch and low end 

[smackoj]

re: "is this a keeper?"  ans. are you trying to make a silk purse out of a sow's ear?  You could always pull the guts and build a JM clone. I see some really nice results from guys like Mark Moser over at Frugal Amps. Or, you could follow the trend which is to use the free listing feature at sneeze-bay and see if someone wants one for 6x what you paid. However, if it is the combo amp with 2x12s, you will have to ship it via OverTheRoad trucker because it prob. weighs as much as a Cummins diesel engine!

sure can't beat the price whatever you decide.   

[Platefire]

Back in the late 70's I bought a older version of the Roadmaster along with a 6-12 cab with HF horn. After a couple of years of that I sold it and went to a small combo. Sounds like you have a more modern version. Mine had a good clean sound but I used a distortion box with it, never could get the OD's to sound right. Plate

[eleventeen]

"re: "is this a keeper?"  ans. are you trying to make a silk purse out of a sow's ear?  You could always pull the guts and build a JM clone. I see some really nice results from guys like Mark Moser over at Frugal Amps. Or, you could follow the trend which is to use the free listing feature at sneeze-bay and see if someone wants one for 6x what you paid. However, if it is the combo amp with 2x12s, you will have to ship it via OverTheRoad trucker because it prob. weighs as much as a Cummins diesel engine!"

Great post. It is very, very hard for the brain to make three decisions at once. The other day, I found two pieces of surplus gear. One has a pair of 6550's in it and 4 qty 12AX7 and other than some bizarre output transformer w/a output impedance of 500 or 600 ohms (guess) resembles nothing so much as a conventional chunky power amp. When I can buy something like that for $25, as I did, 1/4 the value of the two output tubes, I completely refuse to overthink what I might do with it.

The other piece has 5 qty 6C10's in it (which my Hickok 6000 tube tester cannot test, but I see no reason why I cannot fabricate a compactron socket thingy and test 3 qty 12AX7 [or whatever they are] sections one by one, and a pair of EL34's and a pair of EL84's. $25. Those compactrons go for >$30 each (used) on fleabay and so again, am I supposed to overthink this kind of thing?

You are talking about buying obvious value for 20 and 30 and fiddy bucks and if the thing turns out to destroy itself like the tape on Mission Impossible OR if it's worth 5x what you paid for it, it is not going to be a life changer. Don't overthink it. Go and do.

[eleventeen]

And here is today's victim.



This is a rotary speaker, but not a Leslie. I have never seen this one before. Note how there is a spinning disk with three actual speakers mounted on it (!!)

Well, unless I miss my guess, the amp on the right, at 3 o'clock has a pair of 5U4 bowling pins, meaning, it is prolly a 100-watter, like an early Twin. And then I see 2 qty 6550's, with those metal bases. And they are flat sided, so they are prolly newer than the device itself. Not only that, but the claim is that the amp is a Webster something or other, which is a semi-desirable item, and with those tubes, pretty easily salable for $350 on fleabay. So the asking price is $200 which is worth it on its face, but if I can snag it for $175 or $180, then ....???

Anybody know what this is in terms of manufacturer?

Ed: and YES I WILL ask the owner if he has the old 6550's!

[Willabe]

What the heck?    

Look at the size of the motor that spins the speakers. What are the cab measurements?  ~4"x4"x5"?

What size are the 5 speakers, 12"?

What's the motor say for horse power and RPM?

How about a picture of the front face?


               Brad      

[Willabe]

Did a search on flea bay and found 1 that's a different model. Must be a SS as it has no tubes and only 2 speakers that spin. $750.

Do a search for this on flea bay:
 
Circa 1972 Allen Organ Rotary Speaker Cabinet

    
         Brad    

[eleventeen]

Gawd help you if the speakers become unbalanced...it'd walk across the room like a washing machine. (Very good grunge rock effect)  

Well, anyone can ask any price for anything. I just know the asking price is below the parts value. it's prolly about as big as a normal Leslie. I say, once you're gonna blow 30 bucks worth of gas in the truck to buy something completely silly, you might as well get yer money's worth!

A friend of mine wants a DC motor for his drill press so he can make a variable-speed thingy for it. I was REALLY trying to get him to drive HIS truck there (he has to go to stuff for his Mom near the seller every so often) and I would give him the motor for free and kick in $20 for gas. Why isn't that an attractive deal? I just hate doing 60 mile-each-way trips on junkhunts. 

[Willabe]

Gawd help you if the speakers become unbalanced...it'd walk across the room like a washing machine.

The 1 I posted a search for already is unbalanced courtesy of the factory.  

(Very good grunge rock effect)

If you eat some of those funny mushrooms right before you go to a grunge show you'd think the thing was coming to kill you with all that noisy/ratty distortion and screaming going on.      

You'd think he would have weighed 1 of the speakers and glued or bolted a weight where the 3rd speaker should be to keep it balanced.

Let us know how it sounds when you get it.

On a real Leslie, the 15" baffle and also the cab itself, with the slits in it have a big impact on the sound. Lots of sound bouncing around in there, acts like a multi filter at different frequencies.

I wonder how this other design compares in sound to the Leslie?

I also wonder how their controlling the speed and what the speed(s) are?

And yeah, sounds like a good deal for your friend if he goes close to that area anyway.

          
             Brad      

[tubeswell]

I just know the asking price is below the parts value.

That does it! I'll take a dozen of them! I can use them to prop-up the side of my house.

[Willabe]

That does it! I'll take a dozen of them! I can use them to prop-up the side of my house.

 

[eleventeen]

Dude, a homeless family of four could live in this thing and make money charging a quarter for rides to neighborhood children on the rotary speaker disk. I don't need the power supply for that part and I'm sure I can get the speed down to a safe level.

[Willabe]

Dude, a homeless family of four could live in this thing and make money charging a quarter for rides to neighborhood children on the rotary speaker disk.