"Holmes" Amp/speaker information

[Rob Mercure]

Folks, I've got an empty Holmes Pro Compact 210 chassis and cabinet that I inherited several years ago - as best I can tell Holmes was an attempted Peavey knock off. Doing a Google search revealed little about the amps or the company but what I'm really interested in is the ouput power of the amp so that I can reuse the two 10" Eminence square magnet ceramic speakers that came in this combo.
Some hit that I passed over rated the amp as being 120 or 140 W (RMS, Peak?) but somehow this seems excessive for two TO-3 output transistors even if the entire chassis was availablea as a heat sink.
For reference, I compared the magnet and VC size to that of another Eminence that came out of an old Music Man 135 Watt head - 135/4 = 27W +/- 40W assembly - and the magnet is about 4 times the volume and the VC is about twice the size.
Of course you know that olde Eminence speakers produced for any particular manufacturer used crytic factory codes that the current Eminence company claims not to have a Rosetta stone for - but perhaps one of your fine folks has information on the model or perhaps even old service info.

Thanks for any/all help.

Rob

[Enzo]

Eminence codes don't always decrypt anyway. SOmetimes it is just a number. And in any given case, it can't hurt to ask anyway. WHat date codes are on the speaks?

In any case, if you are trying to determine what the amp put out, the speakers is not the way to tell. After all, that 25 watt Celection in a 25 watt amp could just as easily be a 70 watt Celestion in the same amp.

If the pair of TO3s are in there, how is it an empty chassis?

If you want to know what power it put out, check the power supply. A crude measure of that is filter cap rating - 35V caps means rails of 25-30V most likely. 30V rails means about 50 watts into 8 ohms, so I'd call that about a 40 watt amp. Whatever the rail DC might be would also be the peak output voltage, or close to it. Times .707 for the RMS output voltage at clip. FIgure that across the load. Then reduce by a reasonable amount for losses and ineffiencies.

[Rob Mercure]

Hey Enzo,

The speaker designation is 10VPGA16AX but only the first two digits make any sense to me. The back side of chassis was used as a heat sink for the output transistors and there are two empty TO-3 sockets bolted there. While the PT is still on the chassis the rest of the PS - as well as the entire circuit board, is gone. The PT is around 35-0-35 (70 CT) but "tiny" for the claimed output - about the size that Peavey would use for a 40W SS output. But the speaker magnet/VC size appears of greater size than the last sentence would suspect - pretty massive for a 10" speaker. Again, to use a Peavey comparison, about 40W each but putting square Eminence magnets into "round" Peavey "holes" is tricky at best <grin>.

Oh, the "tiny" reverb tank was still in the bag with one of those 4" long CC "reverberation devices" but this one didn't have the "made by beautiful women" tag on it, dang!.

Rob

Ooops, the "date" code is 1980 and straight forward.

[Enzo]

Oh. Well, I hear all the time people selling their "400 watt" amplifier with the four 6L6s. They confuse the power draw rating with output. Maybe the little thing is a 40 watt amp that drew 130 watts from the wall?

On the other hand, 35v AC supply means about a 35v AC signal output max, which into 8 is about 150 watts. If it can hold it up. ANd while it was only two TO3s, someone could design a 150 watt amp with only two. I would rather see more, but you could.

The speaker number means nothing to me, but the 10 for 10". Perhaps the 16 is for 16 ohms?

I just looked over the EMinence web site. The FAQs has some interesting stuff.

[Rob Mercure]

Thanks Enzo, while I did notice the note that information on models made for specific manufacturers was scarce at best I hadn't noticed the FAQ - which does offer to respond to replacement inquiries about specific models. Just sent them an e-mail - thanks for reviewing Eminence's site more carefully than I did. But if anyone has other info on "Holmes Corporation" I would be interested. I'd had this cabinet/chassis for a few years and I remember someone responding in the late 1990s with some Holmes information (now lost as HD's crash) although my specific query at that time concerned the tiny "cute" reverb tank.

But your other "clue" - which I'm ashamed to say that after all these years I didn't notice first - is that the chassis drew 140W from the mains. The outputs did have the entire back chassis to dissipate heat and they were very widely spaced but somehow I expect 85-100% conversion efficiency from the mains to audio output. Due to the amps date and "draw" what would you think 140W of 60 Hz would produce at the speakers?


Rob

[Enzo]

Dunno, I'd be thinking half of that at most.

[MBSetzer]

There might have been a heatsink on the outside of the chassis, is there any sign of heatsink grease on the chassis itself?

Mike

[Rob Mercure]

Hey Mike, the sockets were riveted directly to the back panel and the entire piece of aluminum flatstock was used as the heatsink - the heatsink grease and micas are still there - the rest of the sheet metal is galvanized steel. With only "natural" convection there was about 69.75 sq.in. of heatsink area - I assume that there was some sort of transistor case insulators to keep the user from encountering the +/- supplies but nothing is evident now.

Rob