175 watt modulation transformer

[N4LTA]

There is  a guy on EBAY selling an Apache Heath TX-1 replacement modulation transformer made by Peter Dahl. The label on the transformer is marked 175 watts but the Apache Modulation transformer was much smaller than 175 watts.
I am thinking that the 175 watts (it is on the secondary side with the B+ flowing through it) is the input rating of the Apache. The transformer weighs 14 pounds. Is there any way it is a 175 watt transfomer?

I have been looking for a mod transformer from 150 -200 watts for quite some time. I have access to Hammond Transformers and am looking at the 125 watt audio output transformer ( I have one of these) and wiring several 10H 200 MA power chokes.
I am a Hammond dealer - so I get these at reasonable prices.

[KE6DF]

FWIW

The UTC CVM-3 weighs about 15 lbs and is rated at 125W.

So given that Dahl uses more efficient core materials (Hypersil), it might well be rated at 175W audio output and weigh 14 lbs

[flintstone mop]

The wattage rating is for the entire transformer. There are a few parameters that have to be observed in the design of the transformer. Freq response, Plate current, turns ratio, D.C. volts, etc.

The Dahl unit is probably equal to or superior to the Heath transformer.

Fred

[N4LTA]

^ That's where I come out also. Don't know why Dahl would make a replacement modulation transformer for a 175 watt input amp and rate it twice as big as required, even if if could be made to fit in the required space.

I made an offer on it but he refused. Before I made a counter offer, I did a little research and decided it was not large enough. I told him the reason and now he has plastered in large type in the auction that it is in fact a 175 watt transformer and not a smaller one.

I wish it was what he advertises, as I need one badley. Anyone know where I can fine a 150-175 watt Mod transformer?

[W9GT]

I know folks have run ART-13 mod transformers at outrageous power levels and gotten away with it.  Originally desgned for a pair of 811s moding an 813,  those tranformers look small for even 100 watts.  They frequently show-up on eBay and at hamfests.

The Peter Dahl products generally are very well constructed and have safety factors that are far greater than typical.

73,  Jack, W9GT

[KE6DF]

Before you write off this transformer, perhaps a call to P. Dahl company would make sense.

Is there anyone there to answer the phone? Don't know.

But they should have an answer about ratings of their products -- one would think.

Dave

[flintstone mop]

Could you copy/paste the item number??? Someone here could take a peek.
By the time all of this back and forth replies on this thread take place, someone is going to gobble up that transformer. It might be what you need. Do you know the ratio, or matching impedance for your need and the unit on e-Pay??
Fred

[W4RFM]

The online Peter Dahl catalog, list the secondary as:
0-500-3000 ohms @ 250MA DC (175 watts)

I know from my broadcast engineering experience that Dahl's stuff is over built.  This could be the case here.  The fine print in the Apache manual states that the original transformer could handle more than 75 watts, but is limited with resistors.

[John K5PRO]

I may have an old Hammond special mod transformer that'll handle 175 w. Its large, I have to go out to the storage shed tomorrow and take a peek. I have data for it also. I'll let you know.

[John K5PRO]

I have 3 transformers that may fit the bill.
Stancor A3829 polypedance.
175 watt audio, 9K/6.9K CT to 6.2K/5K/4K/3.3K 300 mA

Hammond 2220
175 watt audio, 15Kp-p CT, 7K/5K/3K 250 mA

SNC 5P352 univeral multiZ 100W, 200 mA
(I've tested this one in a DX100 fine).

Contact me via PM if you need.