Magnetic Componants Inc Transformers?

[Trout]

Great iron, great price!

They started in 1943 building for the US military. They use older machines, probably not from the '40s any more but they still build the iron the old way, with paper and so on. Yes you can still get it Made in Chicago, USA!

I only use other iron when I can't get it from M-C's line.

Try 'em, Don, you'll like 'em!

Just for the record, Magnetic Components Inc is actually owned by another transformer company.

Marvel
Established: 1955
EIA Code: 989 = Marvel Electronics. http://www.marvelelectric.com/index.html
You generally see these in CE Distribution catalogs as well as a few other vendors.

They make Guitar amp transformers at both plants.

[David Root]

That is right, I had forgotten that but Marvel does now own M-C. Don't recall when they bought M-C, but it was not that recently I think, maybe 20 years ago.

However, all the iron I have bought as M-C has the M-C EIA code which is 166 on it, so I assume it is built in the M-C plant in Schiller Park, which is I believe a suburb of Chicago.

[Trout]

That is right, I had forgotten that but Marvel does now own M-C. Don't recall when they bought M-C, but it was not that recently I think, maybe 20 years ago.

However, all the iron I have bought as M-C has the M-C EIA code which is 166 on it, so I assume it is built in the M-C plant in Schiller Park, which is I believe a suburb of Chicago.

100% correct sir.

I live outside Chicago, and both plants are about an hour away (as the crow fly's)

Both companies are top notch. At one time Chicagoland was a transformer super-center, We still have several others here as well.
Not an exacting science, but most of the Fender replacement power transformers that AES/CE carries are from Marvel, and the outputs are from Magnetics.

[Gaz]

I'm wondering if the hot transformers are more a product of the power tubes transferring heat.
After an hour or so of operation, those tubes get cooking hot and could be transferring heat to all around them.
Especially in a tubes down amp.

No, definitely not heat from the power tubes in my case. To reiterate, I've built 6 non-master volume amps with these, they all get hot when cranked up for a while, even when I'm using the 100-watt Marshall PT in a 50-watt. The rectifier, and filtering I'm using is also what's shown in the schem/datasheet that the company provides. I emailed the company, and they said:

"Yes, these are built to withstand high continuous running temperatures without any problems. All of the magnetic wire and layer insulation in this unit is rated for these high temperatures. It is normal for these particular units to run hot. Please rest assured that these should perform well for you."

M Fowler, seems to me like a) your not pushing 2204's the amp very hard or b) the 50-watt PT runs cooler for some reason, as I've only used 100-watts PTs or c) I have been using a different run where thinner gauge wire was used. I've noted that all wires except the heaters has been 22 AWG, which is surprisingly thin, especially for the 120VAC primaries.

Thanks for any more thoughts, I'm still curious why people are having different experiences with these. But again, I've had no failures, and highly recommended these!

[tjauernig]

Excellent stuff. I've used them many many times.

[azatplayer]

Tim! How's it all going? What are you up to these days, still with peavey? Don from aus, you helped me fix a trem couple years ago. Cheers mate.

[azatplayer]

Well got the Transformers today, very very fast. Actually, very fast.
And for all my concerns of rating on the PT, all in vain, the friggin thing is huge! And LOOKS like a marshall PT. Good size OT too. Well, best start making some chassis, as my box of delight arrived from Heyboer as well!

[David Root]

I decided to resurrect this old thread, as I just acquired a 989 Marvel Electric PT, the BF Super PT that AES sells as 989T-P22798.

This going in an application that will use all of its 200mA HT rating and maybe a tad more.

My question is this--anyone know what kind of service factor Marvel puts in their PTs?

Reason is Hammond's 290DX, which is their BF Super PT, is rated 230mA HT current, or 15% higher than the Marvel, but the dimensions of the two are identical. This leads me to think that the Marvel PT is also really a 230mA unit too.

Is this a reasonable assumption? I will only be using the 5V 3A winding on a couple of relays, so virtually no current there, but I will be using all of the 6.3V winding and a tad more at 4.35 A.

[ToneMerc]

Is this a reasonable assumption?

In my experience I think not, I have transformers in that same footprint that externally look the same, but are 115mA apart in HT current. Other than the difference in lead colors, the only way to know any difference would be to weigh them.

If everything was basically the same based on external dimensions, then there would not be these issues of brand X 330-0-50-330V specs PT reading different from than brand Y under the same load.

However, you have to ask yourself what tangible differences would there be in 30 additional mA of current.

TM

[surfsup]

the only way to know any difference would be to weigh them.
TM

I would agree with this. Isn't this also a function of the wire gauge on the windings as well?

I would be interested in learning more about what specific factors cause the current limit in a transformer:

-lamination insulation?
-coil winding wire gauge?

I assume this is more the winding gauge...

[Phil_S]

Wire gauge is a big factor in Amp capacity. I am going to go out on a limb and say that weight can be a decent proxy for solving the problem. You need a good digital scale. If they weigh the same and have the same secondary outputs and footprints, there is a decent chance they are the same on the inside. It would be challenging to be equivalent with a different weight. Specs are specs, wire is wire, and wire has a certain weight.

[ToneMerc]

the only way to know any difference would be to weigh them.
TM

I would agree with this. Isn't this also a function of the wire gauge on the windings as well?

I would be interested in learning more about what specific factors cause the current limit in a transformer:

-lamination insulation?
-coil winding wire gauge?

I assume this is more the winding gauge...

Yes, these are the things that affect it from what I have gathered from having Heyboer wind me numerous PT's.

TM

[rock_mumbles]

I decided to resurrect this old thread, as I just acquired a 989 Marvel Electric PT, the BF Super PT that AES sells as 989T-P22798.

This going in an application that will use all of its 200mA HT rating and maybe a tad more.

My question is this--anyone know what kind of service factor Marvel puts in their PTs?

Reason is Hammond's 290DX, which is their BF Super PT, is rated 230mA HT current, or 15% higher than the Marvel, but the dimensions of the two are identical. This leads me to think that the Marvel PT is also really a 230mA unit too.

Is this a reasonable assumption? I will only be using the 5V 3A winding on a couple of relays, so virtually no current there, but I will be using all of the 6.3V winding and a tad more at 4.35 A.

The AES part# for this PT is: P-TF22798

[David Root]

That's right, I did that from memory. It is a Marvel built PT because the EIA date code on it is 9890714. It does weigh about 7 1/2 lb which is what AES says it is.

Cannot find the 290DX weight anywhere.

I also subscribe to weight = current capacity. It's hard for me to tell for sure until I build the amp what total HT current it will draw but my best guess right now is about 220mA or so. It will have two KT88 in fixed bias parallel SE hanging off it and about another 10-15mA on the pre tubes. An estimated SE UL load line is shown below, courtesy of jazbo8 on the Hoffman forum, for one tube. Just double the mA up for two.

[The New Steve H]

So far they're all I've used, except for two small amps. No complaints.