how good is this DuMont TV/Stereo?
 

Hi Guys,
I got hold of a DuMont color tv and console stereo set, its model number is Model 25-DC-22, chassis model 2103. It is basically a color TV in the middle of the console, and with LP player and FM/AM radio on the sides.

The user manual says it has 9 tubes and 7 solid state devices, and AM/FM multiplex tuner. Garrard 3000 changer with diamond LP stylus, 7 speakers.

I did not know the DuMont brand until now, so I did some google search, and it seems to me that DuMont is a quality brand.

But from the schematic, they use 2 50EH5 as the Single Ended power tube, so it seems my particular set is not their higher end?


Thanks,

how about a pic?

If it is a roundie I'll bet its a RCA CTC-15.

Thanks guys, here is a picture, sorry for the strange angle, it is sitting on its right "shoulder" right now.

what a find!dumonts were among the best sets in the 50s.allen dumont was ahead of his time.fascinating man.after the 50s i am not sure as we never saw one in the shop days.the one at the etf a couple years ago was very nice and well made rca clone.yours look like a very choice item.congrats!

I have a DuMont stereo chassis from this time period. It used a tube type tuner/preamp with a solid-state power amplifier. It doesn't seem like 50EH5 would be used as an output tube in a larger unit like this.

Nice looking set and it's certainly one that does not turn up often! Since it has a rectangular screen, I'd put it in the '65-'66 line. I doubt any '67 models would still have a tube tuner and amp.

In the '50's, Dumont was a higher end TV brand. IIRC, Dumont was bought by Emerson in '57 and many of their products were branded "Emerson-Dumont". And, the quality went down after the Emerson buyout. They still had models in all price categories; but, the quality was not the same as the original Dumont sets. At some point, Emerson was owned by National Union Electronics and I believe the last "real" Emerson/Dumont sets were built in 1970. After that, the Emerson/Dumont TV's were rebadged Admirals. By the '80's, the Emerson and Dumont brands were used on cheap Goldstar and Orion built junk.

And, I can believe that this unit uses a transformerless amp with 50EH5 output tubes as I have seen several large consoles that you would think would have had a decent power transformer based amp inside. Instead, they had a cheap series string hot chassis amp driving small speakers. Having a massive cabinet was just another way into faking out the customer into buying something that wasn't much better sounding than a 5 tube AM radio.

Still, I think your set is a rare find and I'd restore it, if at all possible.

Thanks!

Thanks Chad,
It is -20C outside, so I did not spend lots of time on it. Here are some more pictures of tube replacement charts... I don't know any of the tubes in the TV section, but Radio section is sure tubed.

Thanks a lot for the history, much appreciated!

when I email the previous owner, she said they bought it new at 1966, so I was kind of worried, because I had this impression that the tube to solid state transition happened around 1965, so I double checked with her, and she said she has the tube replacement chart, then I was sure it was tubed! :)

BTW, the output has transformers, two single ended transformers, although I was a little disappointed by 50EH5, I was hoping for 6L6 or 6BQ5 maybe:no:. But it is all good.

Here is a schematic diagram of the radio, too bad videokaram does not allow to upload larger files, so I have to shrink it down...

I see that the TV chassis has a power transformer; so, that's a good sign. There were some BOTL color TV's from that time period that did not have a power transformer and were a series string hot chassis.

The tuner/amp looks like a BOTL model that's basically the same quality as a small table radio from the same period. The only difference is the addition of the extra channel for stereo.

Concerning tube type console stereo's, most of the major companies (Zenith, RCA, Magnavox, Philco, GE, Motorola, etc.) started switching over to solid state models by '63-'64. By '65, I think all of the "big names" had switched to 100% solid state designs. In '63-'64; RCA, Zenith, and others made some hybrid models that contained a tube tuner and a solid state amp. Some of the dapartment store brands (Truetone, Airline, Silvertone, etc) and some of the smaller electronics companies (Olympic, Arvin, Emerson, some Japanese import brands, etc) continued to use tubes up until '66-early '67. By '68, I think it would be safe to assume that all stereo consoles being built were solid state.

As far as solid state color TV's, Motorola introduced the first one, the Quasar works in a drawer, in '67. Then, RCA introduced the CTC40 in '69 and I think '71 was Zenith's first one. However, there were tube based TV's built until the mid '70's. In the case of TV/stereo combinations from the mid '60's to early '70's, it would be safe to assume that most of them contain a tube type TV chassis and a solid state stereo chassis.

Some of these low end stereo's actually sounded pretty good for what they are; but, don't expect floor shaking volume. With a 50EH5, you're probably good for around 1-1.5 watts/channel of undistorted power.

Also, use caution when working on the stereo chassis because it is a "hot" chassis. That means that one side of the AC line is connected to the chassis, either directly or thru a capacitor.

Looking at what I can see of the schematic a little closer, it appears that this unit does have an isolation transformer for the amp; but, still use caution until you know for sure.

EDIT: Yes, it does have an isolation transformer; so, the hot chassis issue shouldn't be a problem.

Can't quite see, but it looks like they used a power transformer as an isolation transformer to run the tuner/amp.