Any body have any info on garnet amps?
I'm digging for the spec. of the interstage used for phase inversion.
One scheme had it identified as a 11HB001 ( or 11H8001).
garnet interstage
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Andy Le Blanc
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garnet interstage
lazymaryamps
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Sonny ReVerb
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Re: garnet interstage
The BTO schem I have shows '1HB001' or '1H8001'. The B/8 is hard to make out. I can't seem to find any other info on it. (Well, I did find the PA amp shows an '11HB001'.)
Here are some good gut shots if that helps. That is some serious iron in that BTO!!!
This surplus place has several 'Hollytran' interstage transformers. One of those might work, if you don't have one in that scrap pile of yours.
Here are some good gut shots if that helps. That is some serious iron in that BTO!!!
This surplus place has several 'Hollytran' interstage transformers. One of those might work, if you don't have one in that scrap pile of yours.
"The blues is the roots, the rest is the fruits." - Willie Dixon
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Andy Le Blanc
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- Location: central Maine
Re: garnet interstage
Thank you very much, I hadn't found the interior shots yet. Garnet and Selmer
had that type of transformer inversion in more than a few models.
I've seen a few references on web pages dedicated to jukebox restoration,
with this hook up as a way to rescue the inverter, but the usual dress uses
an interstage with a primary. It looks wonderfully simple, got try it.
If I can find more info there's hope. All I got is an old stancor universal.
But the size of the small transformer in the garnet shot looks similar,
it might be a non critical part too, but I'd like to know.
I've never heard anything derogatory about garnet, You can still get the
knobs, and that dirt box looks neat.
Those transformers are menacing, looks like a "don't skimp on the pate' " design choice.
40,000 unit by hand, there's a cottage business.
had that type of transformer inversion in more than a few models.
I've seen a few references on web pages dedicated to jukebox restoration,
with this hook up as a way to rescue the inverter, but the usual dress uses
an interstage with a primary. It looks wonderfully simple, got try it.
If I can find more info there's hope. All I got is an old stancor universal.
But the size of the small transformer in the garnet shot looks similar,
it might be a non critical part too, but I'd like to know.
I've never heard anything derogatory about garnet, You can still get the
knobs, and that dirt box looks neat.
Those transformers are menacing, looks like a "don't skimp on the pate' " design choice.
40,000 unit by hand, there's a cottage business.
lazymaryamps
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Sonny ReVerb
- Posts: 342
- Joined: Sun Feb 05, 2006 6:54 pm
Re: garnet interstage
I was thinking you should probably check out Hammond, since Gar was a Canadian, eh? Angela carries some of their interstage transformers.
Being a child of the 70's (when BTO [the band] reigned), I was interested in Garnet. They had some interesting products, such as the Herzog. Gar's designs were a bit off the beaten path. I'd like to get his book one of these days.
I've read that most companies abandoned interstage transformers because a tube PI was so much cheaper to produce. Sounds like it could be a niche for a 'booteeker'.
Being a child of the 70's (when BTO [the band] reigned), I was interested in Garnet. They had some interesting products, such as the Herzog. Gar's designs were a bit off the beaten path. I'd like to get his book one of these days.
I've read that most companies abandoned interstage transformers because a tube PI was so much cheaper to produce. Sounds like it could be a niche for a 'booteeker'.
"The blues is the roots, the rest is the fruits." - Willie Dixon
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Andy Le Blanc
- Posts: 2582
- Joined: Sat Dec 22, 2007 1:16 am
- Location: central Maine
Re: garnet interstage
Nothing in the hammond catalog, looks like a tapped choke.
The retail costs of tube, socket and components, at this point can be very high.
more so than a three dollar tranny.
Its one of two or three inverter configurations I haven't tried, MM might,
but it not worth the BS price. If I can lay my hands on one, or a selmer....
The spec. would be worth it.
The retail costs of tube, socket and components, at this point can be very high.
more so than a three dollar tranny.
Its one of two or three inverter configurations I haven't tried, MM might,
but it not worth the BS price. If I can lay my hands on one, or a selmer....
The spec. would be worth it.
lazymaryamps
Re: garnet interstage
It's actually a center-tapped choke. Cf. the enclosed scan from Gar's book, "The How and Why of Guitar Tube Amps as 'Gar' Sees It" (recommended BTW).Any body have any info on garnet amps?
I'm digging for the spec. of the interstage used for phase inversion.
One scheme had it identified as a 11HB001 ( or 11H8001).
Garnet (the company) is still around, why don't you contact them at info @ garnetamps.com?
You do not have the required permissions to view the files attached to this post.
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Andy Le Blanc
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- Location: central Maine
Re: garnet interstage
cool ..... does the reference have a ISBN....
I understand the limitations design choices can make for you, it the application.
haven't gone so far as to try to contact garnet directly, its a holiday weekend.
I also understand that it is a choke, or inductive load, I'd like to find the spec..
I might be able to get close with a small opt but I fear the X R on most is too low for the application.
I understand the limitations design choices can make for you, it the application.
haven't gone so far as to try to contact garnet directly, its a holiday weekend.
I also understand that it is a choke, or inductive load, I'd like to find the spec..
I might be able to get close with a small opt but I fear the X R on most is too low for the application.
lazymaryamps
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Sonny ReVerb
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- Joined: Sun Feb 05, 2006 6:54 pm
Re: garnet interstage
Gar's book looks great, but it's priced up there with KO'C's books. Unemployment sucks, in case you happen to be one of the fortunate working folks. I think they only sell the book direct from the company or maybe some select resellers. I couldn't find it at Amazon...FYL wrote:..."The How and Why of Guitar Tube Amps as 'Gar' Sees It" (recommended BTW).
"The blues is the roots, the rest is the fruits." - Willie Dixon
Re: garnet interstage
Couldn't you use an output transformer that has a center tapped primary?
That is, just use the primary side as the choke?
That is, just use the primary side as the choke?
Tom
Don't let that smoke out!
Don't let that smoke out!
Re: garnet interstage
No ISBN on my copy (a first edition, so maybe one was obtained later).cool ..... does the reference have a ISBN....
Only available direct from Garnet AFAICT
http://garnetamps.com/order_b.htm
Re: garnet interstage
I've just checked my files and couldn't find more amp-specific info.I also understand that it is a choke, or inductive load, I'd like to find the spec..
Re: garnet interstage
Andy, of all people, I am one of those who really understands the drive to do it the way it was done. However, chances are, this piece of iron is made from unobtanium, meaning you'll have to send it off to a winder to have it unwound and rewound. I am aware that MM charges $illy for such work. I suspect it won't be cheap anywhere. (Find an "old guy" who can do it by hand, and find him before he dies off! Try the "local" AARL ham crowd.)
There is a slim chance it doesn't have many turns. You might take it apart on your own and see what you can do with it. A while back, I had an OT with one of the primary leads disconnected from the end of the winding. I had no luck digging it out. Figuring I had not much to lose, I opened it up. I applied a little bit of sandpaper to remove varnish from the lams, and split them off one by one using a razor knife, stacking carefully as I did it. After freeing the core, I was able to attach the orphaned lead. It afforded me a birds eye view of an OT. There are lots of turns...I'm thinking thousands. You wouldn't want to wind such a thing without proper winding equipment. But your choke may be a whole lot simpler. Maybe you'll find the problem and mend it? Does your ohm meter give you any hints?
Caution, this is time consuming and you may end up with a useless pile of lams. OTOH, if you free the core, you maybe be able to get the core rewound for a whole lot less than if you send the transformer intact.
To reassemble, just reverse what you did, stacking carefully. Get a spray can of hi-temp Sprayon insulating varnish from McM-Carr for $5. Bake it to ~180F, spray while hot. This will suck the varnish into the lams.
Maybe you should think about building out the concertina, as suggested by that bit of documentation someone posted. It can be done with a 6J5 with 10K plate load and cathode resistors.
Just my 2 or 3 cents....FWIW.
Phil
There is a slim chance it doesn't have many turns. You might take it apart on your own and see what you can do with it. A while back, I had an OT with one of the primary leads disconnected from the end of the winding. I had no luck digging it out. Figuring I had not much to lose, I opened it up. I applied a little bit of sandpaper to remove varnish from the lams, and split them off one by one using a razor knife, stacking carefully as I did it. After freeing the core, I was able to attach the orphaned lead. It afforded me a birds eye view of an OT. There are lots of turns...I'm thinking thousands. You wouldn't want to wind such a thing without proper winding equipment. But your choke may be a whole lot simpler. Maybe you'll find the problem and mend it? Does your ohm meter give you any hints?
Caution, this is time consuming and you may end up with a useless pile of lams. OTOH, if you free the core, you maybe be able to get the core rewound for a whole lot less than if you send the transformer intact.
To reassemble, just reverse what you did, stacking carefully. Get a spray can of hi-temp Sprayon insulating varnish from McM-Carr for $5. Bake it to ~180F, spray while hot. This will suck the varnish into the lams.
Maybe you should think about building out the concertina, as suggested by that bit of documentation someone posted. It can be done with a 6J5 with 10K plate load and cathode resistors.
Just my 2 or 3 cents....FWIW.
Phil
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Sonny ReVerb
- Posts: 342
- Joined: Sun Feb 05, 2006 6:54 pm
Re: garnet interstage
Center-tapped chokes:
Here's a TubeCAD example: http://www.tubecad.com/2004/blog0006.htm
A little PM DIY article about chokes including a CT.
An interesting PS article addressing an alternative using an audio transformer.
This one is for a different application, but uses a filament transformer in lieu of a choke.
Just tryin' to stir those brain cells...
Here's a TubeCAD example: http://www.tubecad.com/2004/blog0006.htm
A little PM DIY article about chokes including a CT.
An interesting PS article addressing an alternative using an audio transformer.
This one is for a different application, but uses a filament transformer in lieu of a choke.
Just tryin' to stir those brain cells...
"The blues is the roots, the rest is the fruits." - Willie Dixon
-
Andy Le Blanc
- Posts: 2582
- Joined: Sat Dec 22, 2007 1:16 am
- Location: central Maine
Re: garnet interstage
there's no such thing as unobtainium, $illy yes, I'd love to use a regular off the
shelf part, as long as I know what I'm shooting for, you make a SE OPT from a
junk microwave, don't really care too but you can. Transformers are like guitar pick-ups.
It's the tools needed for easy fabrication. I can make a pick up with an old
sewing machine and a double boiler on a kerosene lantern to heat the wax.
Thank for the responses, it's very appreciated. There are only so many ways
to accomplish phase inversion, I'm not a cloner and I already use the concertina inverter,
3 or 4 variations of cathode coupling and a good half dozen forms of paraphrase.
Interstage transformer inversion is one of the few left to explore.
Gar's book is one I don't have, hopefully I can swing a copy, a large varied
selection of reference is better than any kit, attempt to clone or any bench tool for that matter.
Hopefully it doesn't play up to the mojo BS that so many current publications
do just to sell tubes or mods or clone kits, or some other useless added feature.
A couple points seemed to come out of that tube cad journal entry.
There is a relationship of the capacitance of G1 to the winding ratio of the
inductor you using. Its increased by the square of the winding ratio.
There's also the mention that it works best with high-transconductance tubes.
So if I can find a few basic spec's, there's most likely a nice optimum to use.
shelf part, as long as I know what I'm shooting for, you make a SE OPT from a
junk microwave, don't really care too but you can. Transformers are like guitar pick-ups.
It's the tools needed for easy fabrication. I can make a pick up with an old
sewing machine and a double boiler on a kerosene lantern to heat the wax.
Thank for the responses, it's very appreciated. There are only so many ways
to accomplish phase inversion, I'm not a cloner and I already use the concertina inverter,
3 or 4 variations of cathode coupling and a good half dozen forms of paraphrase.
Interstage transformer inversion is one of the few left to explore.
Gar's book is one I don't have, hopefully I can swing a copy, a large varied
selection of reference is better than any kit, attempt to clone or any bench tool for that matter.
Hopefully it doesn't play up to the mojo BS that so many current publications
do just to sell tubes or mods or clone kits, or some other useless added feature.
A couple points seemed to come out of that tube cad journal entry.
There is a relationship of the capacitance of G1 to the winding ratio of the
inductor you using. Its increased by the square of the winding ratio.
There's also the mention that it works best with high-transconductance tubes.
So if I can find a few basic spec's, there's most likely a nice optimum to use.
lazymaryamps
Re: garnet interstage
Andy, I've got a Gibson GA20-RVT that uses an interstage PI tranny. IMO, it's nothing special. Actually, it blew and I put the generic Hammond in it's place. Well, what little mojo that amp had was gone with the Hammond in there.
You are right about unobtainium. About a year ago, someone has an auction for a full set of iron from the GA15-RVT, which uses the same PI tranny. It's one of those projects that's been sitting....
Anyway in my quest for a replacement, I acquired a couple of 1:3 interstage trannies that are center-tapped. I've also got a couple of filament trannies, one of which puts out over 7.0V under load and I'll probbably never use it. Might be perfect for you.
PM me if you are interested. I can send you some pictures.
Phil
You are right about unobtainium. About a year ago, someone has an auction for a full set of iron from the GA15-RVT, which uses the same PI tranny. It's one of those projects that's been sitting....
Anyway in my quest for a replacement, I acquired a couple of 1:3 interstage trannies that are center-tapped. I've also got a couple of filament trannies, one of which puts out over 7.0V under load and I'll probbably never use it. Might be perfect for you.
PM me if you are interested. I can send you some pictures.
Phil