OT: Guitar Amp, What Have I Got?

This came as part of a lot i bought from the estate of a friend. What i know about guitars and amps would fit in a thimble and still leave room for a finger. The 12AX7's and EL84's are Mullard, the rectifier simply says "made in Holland" so i assume Amperex. The speaker is a 10 or 12 inch Magnavox field coil. There no big "can" filter cap on the top side of the chassis, so is it safe to assume this is a design that uses the field coil as a smoothing choke for the P/S?

All comments and info appreciated, i'd also be curious about current value.

http://i107.photobucket.com/albums/m.../deltaamp1.jpg

http://i107.photobucket.com/albums/m.../deltaamp3.jpg

http://i107.photobucket.com/albums/m.../deltaamp2.jpg

http://i107.photobucket.com/albums/m.../deltaamp4.jpg

Very nice. Rare to the point of being overlooked by the 2007 official Vintage Guitar Price Guide. With English and Dutch tubes maybe one of our European members knows.

In the meantime, I'll ask around at The Amp Garage and a couple of other places. Lot's of British manufacturers never make it to the guide. The magnavox field coil speaker and the attempt at a ported enclosure indicate maybe a prototype or a custom builder.

Dan

The cabinet is 3/8 plywood and very resonant, there are two wooden "posts" that don't appear to have ever been permanently affixed, they're a pressure fit between the baffle board and the back much akin to the sound post in a hollow body acoustic instrument. Is this a way for the user to tune/voice the cabinet resonance to their liking?

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Originally Posted by bowtie427ss

The cabinet is 3/8 plywood and very resonant, there are two wooden "posts" that don't appear to have ever been permanently affixed, they're a pressure fit between the baffle board and the back much akin to the sound post in a hollow body acoustic instrument. Is this a way for the user to tune/voice the cabinet resonance to their liking?

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I'm guessing to stop a rattle. Marshall and HiWatt cabinets use a baffle to backboard brace but it's glued in place on the baffle and pressure fit to the backboard.

Me and Leo Fender just let them rattle.

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Me and Leo Fender just let them rattle.

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LOL

Thanks for your input.:thankU:

This was destined for a yard sale, i walked past it several times in the course of moving a couple pianos, a Kustom 200 PA head and columns, a couple Wurlitzer sidemen, etc... as i was checking to see that everything in my lot made it on the truck, i had a chance to ask one of the family members about the amp. Her reply "they said they're going to put 60 dollars on it in the yard sale, but will take the best offer". On total impulse i said i wanted to take a quick look at it, thinking to myself i simply wanted to make sure it had a power transformer and not some cheapo that strings a bunch of filaments in series, and if it did i'd give them their asking price for it. Long story short here it is.

Serious funkiness.

I think the logo is swiped from a Delta power tool.

Amp may be home brew wasn't uncommon in the old days

In the days of Field coils, Delta as in Delta blues was not a common expression...that came MUCH later.

Get on Usenet at all? If not I'll post a link to this in alt.guitar.amps

Will relay any comments

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I think the logo is swiped from a Delta power tool.

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I'll have to admit this very thought occurred to me.

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Amp may be home brew wasn't uncommon in the old days

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I should have mentioned that on the inside of the removable panel there is a rubber ink stamp from a small music store in the next little town up the valley from me, said store closed circa 1970-71.

Also inside this panel is a very crudely drawn tube location diagram. There are no other indications of a manufacturer anywhere. The cabinet quality, fit and finish i guess you'd call it seems pretty high for a one off DIY. But there are some other things like wires that pass thru chassis holes without a grommet or any other protection seems a little primative for a factory assembly.

Could this have been a kit?

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Get on Usenet at all? If not I'll post a link to this in alt.guitar.amps

Will relay any comments

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I do not, and would greatly appreciate that.

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Originally Posted by Old Guy

I think the logo is swiped from a Delta power tool.

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Maybe, but the font doesn't look very Delta to me. Even if it is, it looks later than the amp itself.

Well, you just have to have somebody play it. It may have more mojo than a person could stand. Then again, it may be worth whatever you can get for the tubes and about the same price you paid.

This guy is well known for knowing everything, or having contact with somebody who does:
Gruhn Guitars Inc
400 Broadway
Nashville, TN 37203-3931
(615) 256-2033
Gruhn Guitars

He charges for appraisals of very high dollar guitars but is interested in everything. He might like to look at the pictures and comment on it. Guys like Shot Jackson, Bob Crooks, and Hartley Peavy knew just about everybody and were into everything. Gruhn was around in those days.

Many thanks for the contact info Airboss.:thankU:

I'm truly not obsessed with the value, i'm confident i can always get my investment back out of it and that's really all that matter concerning value. The main reason i grabbed it is because i know these people and their situation as well as the yard sale climate around here, somebody would for sure lowball them and put it on ebay with a ridiculous BIN/best offer the same day. You don't want to know what the B3 and pair of 145's or the steinway XR went for, they let those go before they found me. The owner was a friend of ours, but after he passed the family did not know how to contact us, i'd have gadly brokered those instruments for them and gotten them fair market value. Sadly, it all went for about the top dollar value of one of the leslies long before i was on the scene

You won't see this amp on ebay while i'm it's owner. My goal with it i think is quickly becoming to just put it in the hands of somebody who will use/appreciate it for what it is, if i can make a small/fair profit in the process, all the better.

This is the only place i've posted the amp, i have a lot of respect for the veteran members here, i've learned much from them and they're the kind of folks who's possession this belongs in. I knew at least a few of you play and would probably be interested. When i get done stroking and coveting it, this is where i'll offer it.:D Oh, and the next owner will be the first to power it up in what i'd guess is many years judging from the dust layer and the fact the owner was a keyboardist.

I wonder if that's an old Delta box now cleverly disguised as an amp case?

Cool find! Too bad you missed out on the Hammond. :(

The lack of top-mount cans isn't uncommon, don't be surprised if there's a couple of 15-30mfd paper axials underneath.

That's a real puzzler, the FC speaker seems out of place with a tremmie circuit timeline-wise. The latest FC speaker in an MI amp I've seen was from an M2 Hammond, both of which now reside in a similar style guitar amp. :)

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Originally Posted by Audio_by_Goodwill

Maybe, but the font doesn't look very Delta to me. Even if it is, it looks later than the amp itself.

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Way later than the amp.:2thumbsup:

Type fonts often change over time.

Regardless. I would bet 50 bucks it's not the original logo.


I am 99% certain it's home brew.

Probably a 50-ish DIY from scavenged parts.

Still, probably has value...nice display piece for a collector.

It's generated quite a bit of interest over at the Amp Garage. Puzzlement too.

The reason I suggested Gruhen is that he would know if it was a manufactured item or a homebrew. From experience, in those days the only way to do panel like that was to use letter transfer; a tedious and difficult to master art. That is, without the thing coming out looking like a ransom note cut from the newspaper. You'll be able to tell by examination if it's a silk screen. I suspect if the panel is silk screened there was some limited production. Or a kit.

It may not have been a guitar amp. Though I hadn't noticed the tremolo. It may have been built for accordion or some early electronic keyboard?

I don't want to know what the Steinway or B3 went for let alone the leslies. My leslie is in the building stages from a blemished (bad) new walnut cab built for Leslie/Suzuki, and a bunch of parts scavenged from murdered and looted Leslies. I'm probably going to bi-amp and use an Altec in the bass section.

It's a sad deal when a musician goes and the family doesn't know what to do about the stuff. I've heard tales but never participated in one. I've known guys who have paid $200 for a '50s Selmer #7 tenor at garage sales. My future widow has a list of guys to help supervise the disposition of my crud. Sad tale. Good for you on paying the asking.

In any case it has generated a lot of interest at The Amp Garage. About half of us in the business professionally. Most don't want to OWN the thing, but would sure like to get some detailed gut shots of the chassis underneath, along with transformer OT winding ratios and what not. Then the thing should have a place of honor amongst a collection of such things. There are a variety of ways for instance to do a phase inverter and even by the fifties it was usually accomplished with a tube. So maybe it's a parallel pair or there's a driver transformer under the hood? Those sorts of questions. How do you implement trem without an additional tube I dunno. Where's the trem tube? Did he use bias oscillation or a photo conductor gizmo? How did he make it oscillate?The two halves of the 12ax7 are used as input and recovery after the tone stack usually. No pi tube, no trem tube, and why then all the inputs? There are more or less two chassis; the one behind the face plate and the one with the power (looks like Stancor) transformer and the output tranny sticking out the side. All of these things point to a very clever hobbyist or a production prototype you know? Why make a home brew so compact and bitchin' looking? That's why I mention Hartley and Bob Crooks. Those guys had their hands in a lot of stuff before they had viable companys. Leo didn't come on the scene until the late '40s and he sorta normalized things. Before that there were guitar amps but they were all weird and unique and didn't work very well. If it was a 40's design though you'd expect octals. Not that tube lineup.

It's of historical interest to a bunch of us. We'd like to know what's going on in there.

Dan

There's also Magnatone and Supro. These folks made amps for Sears, Montgomery Wards, and other large retailers in addition to their own brands. The cabs often have that sort of ply construction and covering. Leo used pine for the sides and plywood for the baffles. Made them road worthy. Lot's of questions.

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Originally Posted by bfish

Cool find! Too bad you missed out on the Hammond. :(

The lack of top-mount cans isn't uncommon, don't be surprised if there's a couple of 15-30mfd paper axials underneath.

That's a real puzzler, the FC speaker seems out of place with a tremmie circuit timeline-wise. The latest FC speaker in an MI amp I've seen was from an M2 Hammond, both of which now reside in a similar style guitar amp. :)

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My 1956 M3 has a Jensen field coil. Hammond didn't change for good until the late '50s or early '60s; and then the PM speakers and FC speakers seem to be mixed up by serial number. Like they would say "how we gonna do this one, FC or PM?" while they used up stock.

Funny amp. Wonder what the Dim<->Bright knob does?

OK, i don't have a lotta time right now, but i did manage to get a few pics for those very inquiring minds.

Again, thanks for all the input on this folks!

One thing i have to relate, and i'll back it with some pics when i have some time to clean it up a bit. This cabinet is really well made, like by an experienced cabinet builder, id be proud to call it my work. That being said, IMO if it's DIY, it's a top shelf example.

Honestly, when i look at it i get the feeling of "sears and roebuck". Dig those extra holes in the chassis, one size fits all?

The pots on the control panel are all marked "2 meg" and one of the numbers is 1376138, which to me suggested CTS 38th week of 61 making me think it's circa '62 vintage.

FWIW, i think the Delta emblem was swiped from an 80's water faucet display in a plumbing store.

http://i107.photobucket.com/albums/m...derchassis.jpg

http://i107.photobucket.com/albums/m...panelunder.jpg

http://i107.photobucket.com/albums/m...ie427ss/PT.jpg

http://i107.photobucket.com/albums/m...e427ss/OPT.jpg

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Originally Posted by Panomaniac

Funny amp. Wonder what the Dim<->Bright knob does?

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I think it simply dims or brightens the pilot light(mechanically by moving the bulb in relation to the lens) it looks to be connected to the heater circuit.

It's definitely push pull. Not parallel. I think the FC speaker was added. It has flying splices covered with tape. There are enough tubes to do a bias type trem but I've got to spend more time with it. Fixed bias supply appears to be implimented with that metal case diode over between the filter cap and the big power resistor. I'll post these over at The Amp Garage afterwhile. I agree '60s and very weird in some areas. There have been amateur hands in there.

Good job!

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Originally Posted by bowtie427ss

it looks to be connected to the heater circuit.

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Hmmmm..... Kinky!

It looks well-made and might appeal to the blues-harp crowd as well as guitarists.