Greetings,
We're trying to find a vendor that can rewind a small mains TX from a S/E guitar amp. The primary winding is open. I have the voltage and current specs. The amplifier it came out of belongs to a client and is not worth very much, so Mercury Magnetics, etc. is out.
Any leads are much appreciated. TIA!
Regards, Jim
We're trying to find a vendor that can rewind a small mains TX from a S/E guitar amp. The primary winding is open. I have the voltage and current specs. The amplifier it came out of belongs to a client and is not worth very much, so Mercury Magnetics, etc. is out.
Any leads are much appreciated. TIA!
Regards, Jim
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Greetings,
First, sorry for posting in the wrong forum. Figured it really could have gone either way.
Thank you all for the replies as well!
So, we have dozens and dozens of *similar* transformers in stock, but unfortunately, nothing that would be a "transparent" swap. The amp uses a 6V rectifier tube, so the 6V secondary is much higher current then most similarly sized units. Next, the plate winding is on the lower side of the voltage range for a single 6V6 output. Lastly are the space available and mounting constraints and of course, our clients' desire to keep it as original as is "reasonable". I've checked just about every transformer source and have not located anything that meets all requirements.
I'll update my post later today with the secondary specs and take some pix; perhaps one of you has a similar beast in the pulls box? Thanks for reading!
Regards, Jim
First, sorry for posting in the wrong forum. Figured it really could have gone either way.
Thank you all for the replies as well!
So, we have dozens and dozens of *similar* transformers in stock, but unfortunately, nothing that would be a "transparent" swap. The amp uses a 6V rectifier tube, so the 6V secondary is much higher current then most similarly sized units. Next, the plate winding is on the lower side of the voltage range for a single 6V6 output. Lastly are the space available and mounting constraints and of course, our clients' desire to keep it as original as is "reasonable". I've checked just about every transformer source and have not located anything that meets all requirements.
I'll update my post later today with the secondary specs and take some pix; perhaps one of you has a similar beast in the pulls box? Thanks for reading!
Regards, Jim
Which are????????
Brand and model of amplifier?
Using numbers instead of descriptions will help immensely.
It usually is.
Modern designs often use side by side plastic separated bobbins to improve isolation, meet hipot requirements, etc, but guitarheads are "classic minded" to say it politely, they even consider *paper* bobbin transformers better, go figure, so most probably that transformer has primary winding inside .... which means the full transformer needs unwinding and rewinding.
Quite doable of course, but means expense will be higher than it seems.
In fact, having the full specs, winding a new one will be cheaper.
One detail: primary burnt, maybe you do NOT want an exact copy but a somewhat improved one, such at least using next higher wire gauge for primary.
If space is too tight may mean designer compromised to make it tinier, you might do well in accepting a slightly larger replacement.
transformer specs
Greetings,
The mains transformer is from a Masco MAP-105 guitar amp (the print is dated 1947). It was a low budget, "student" type amp. The listed transformer specs are:
Primary: 117 VAC .27 A Secondaries: 6V3 @ 1.4 A, 250-0-250 @ 39mA
The tube compliment is a single 6V6 output, a 7F7 small signal and a 6X4 rectifier.
It's a Z mount form factor: outer stack dimensions are 2.5" x 3", the end bell that goes thru the chassis is about 2.25" x 2.5.
Does anyone know of a rewind service (preferably in the US due to shipping costs)? Pix here:
analogbros.com - /pictures/Masco/
TIA!!
Regards, Jim
Greetings,
The mains transformer is from a Masco MAP-105 guitar amp (the print is dated 1947). It was a low budget, "student" type amp. The listed transformer specs are:
Primary: 117 VAC .27 A Secondaries: 6V3 @ 1.4 A, 250-0-250 @ 39mA
The tube compliment is a single 6V6 output, a 7F7 small signal and a 6X4 rectifier.
It's a Z mount form factor: outer stack dimensions are 2.5" x 3", the end bell that goes thru the chassis is about 2.25" x 2.5.
Does anyone know of a rewind service (preferably in the US due to shipping costs)? Pix here:
analogbros.com - /pictures/Masco/
TIA!!
Regards, Jim
MAP-105 is a good little amp. Not even that little; it may be for small clubs at SPLs you can talk over (so, pre-1954).
It is hard to believe that rewinding PLUS ad-hoc shipping two ways is cheaper than drop-shipping stock product from a major factory. Let's at least write that out and see if the customer faints.
Hammond 290AAX, $51-$66 ($67.50 shipped from Mouser), physically good, 490VCT@90mA, 6.3V@1.25A, 0.6VA low on heater winding but 11VA high on HV winding
It is hard to believe that rewinding PLUS ad-hoc shipping two ways is cheaper than drop-shipping stock product from a major factory. Let's at least write that out and see if the customer faints.
Hammond 290AAX, $51-$66 ($67.50 shipped from Mouser), physically good, 490VCT@90mA, 6.3V@1.25A, 0.6VA low on heater winding but 11VA high on HV winding
Attachments
It will certainly work fine there. In theory filament winding is slightly overstretched, in practice no big deal.
If largerv than original, you have 2 options:
* mount it fully over chassis.
or,
* IF you insist on mounting "like the original one", *maybe* it fits on original cutout; if not, a hand nibbler can resize the cutout.
If largerv than original, you have 2 options:
* mount it fully over chassis.
or,
* IF you insist on mounting "like the original one", *maybe* it fits on original cutout; if not, a hand nibbler can resize the cutout.
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