Philips 794 Receiver?

[Oilmaster]

You're right, these are two different product lines. Perhaps like you mentioned, the US built Philips gear may have come from the former Magnavox factories. Looking back at your pics, a couple of building differences are clear. The US model has radial power caps soldered on a PCB, while the home market gear always had loose power caps binded to the chassis.

Two different models with the same designation, only seperated by the suffix....

The /xx suffix was normally used to define modification revisions, which were always very nicely pointed out in the service manuals. So when I purchase a Philips unit, the service manual nicely lists all modification which have to be accounted for compared with last built revision if you haven't the last revision. The Philips documentation of that era was very good maintained for that.

Too bad you may not (easily) find the 70's European Philips gear in the US, because main stream priced Philips gear does actually have lots of Class A topology. Because Philips really went for plastic chassis and front plates, they looked much cheaper then was actually inside it (e.g. check out the 22RH561, excellent unit). Therefore, like in the US I guess, they lost the commercial battle with the Japanese, despite that a Kenwood KA-3500 is 3 times less technology then the 'plastic' Philips units. We can buy 70's Philips units by dozens for $20 to $50 each (yep, even the ones with aluminium fronts), but few people like them... too bad, I bought some to strip them for homebrew projects. Hehe.

 

[bmaarseveen]

Ozzy,

I hooked my Philips 794 receiver to 'normal' high end speakers. Sounds great at lower volume, but a bit flattened out on higher volume. Probably due to the average end stage as you suggested in an earlier post (6 years ago . Is it correct to assume that with the active MFD speakers such as the 22RH541 you would need less of the end stage, or maybe even just use the class a pre amp?

Bart

 

[Aeon_MK]

Ozzy,

I hooked my Philips 794 receiver to 'normal' high end speakers. Sounds great at lower volume, but a bit flattened out on higher volume. Probably due to the average end stage as you suggested in an earlier post (6 years ago . Is it correct to assume that with the active MFD speakers such as the 22RH541 you would need less of the end stage, or maybe even just use the class a pre amp?

Bart

The power stage is not involved when connected via MFB, which is basically a pre-out output from the pre-amplifier stage. (I am just digging in one 22AH594 amp, one 22AH794 receiver and another more powerful 22AH796 receiver, all with the same topology)

 

[KentTeffeteller]

Nice unit, but I never knew that Philips had a factory in the USA ! Notably because I'm from nearby Philips' hometown Eindhoven in Holland, with plenty of friends and neighbours working in Philips' factories at the time. In Europe, most of such equipment would be built in Holland until they closed the hifi gear factories and moved them to Singapore after 1980. It seems that Philips did have a dedicated factory for North America. Hmmm...

Anyway, when you search for information on any Philips gear, always put the prefix '22'.

Like that, you will easily find a free service manual.... (http://www.eserviceinfo.com/index.php?what=search2&searchstring=22AH796) (if you are not familiar with it, make sure you download all parts by clicking on the 0,1,2,3 by 'multipart' in the next window).

Some recommendations: the OPS emitter resistors are often underrated in Philips gear from that era. Check carefully the surfaces off all power resistors for cracks and the like, and replace them with 1 or 2 watt higher rated resistors. All caps are more or less still in production; the original Philips capacitor factory was sold to BC, then Vishay bought BC. Up to today, some Vishay BC capacitors still carry the original Philips coding (and blue colored).

I haven't check out the schematic myself, but in that era Philips often had output stages which were running in pure class A for the first 10 watt (and therefore the heatsink can be slightly warm at lower output volume). Like the entire tone control part, which was definitely not a classical Baxandal circuit, but rather a cascade of separate tone control stages with a class A buffer stage at the end of each tone control. Very particular, but it had that typical clear and transparant Philips sound.

This era of Philips built in the USA, was built by Magnavox. And their main factories then were in Greeneville, Tennessee. Cabinet plant was in Jefferson City, Tennessee. Administration was in Strawberry Plains/Knoxville, Tennessee.