Metropoulos Forum

I've received the era correct paper voice coils that came in the old pre rola speakers. They're made of Kraft paper, and the first four are getting here later today. The look/color are identical to some blown old Celestions sent in here for rebuilding.

Since I recently picked up a late 67 slant cab with 20w 003 coned pre rola G12M's in it (that sounds insane), I finally have the right speakers to do comparisons with the ones I'll offer.

I'm going to put the new M75 PVC prototypes in my 68 slant BW cab, and compare directly to the 67 slant with the original 20w G12M's. I'll have this tested out later today, 10/03/11

When they get here I am not going to variac these speakers, I'm just going to play them in with my 50w Metro clone (NOS glass, SoZo caps, Mercury RS trannies) so I won't have comparison clips up for awhile, but maybe by March I can post some clips for all of you to hear.

These will be sold without warranty as the paper coils can overheat if sent too much power, so that's the only way I could get this done to offer them. Not sure what the price point will be yet, although I doubt it will be much of an upcharge over the standard price, if any. More on that later.

Yeeeehaaaaa!!!!

You know that you just made my day, don't you?

H75 PVC, baby...oh YEAH!!!

Jim, just for the history of this; when did Celestion use these paper voice coils? When was the transition to the later (Kapton?) voice coils? And what makes them sound different? I was sort of under the impression that the early G12M20 and G12H25 differed from the later G12M25 and G12H30 mostly in the cone (H1777 or SP444 for the former, Pulsonic 003 or 014 for the latter), but I take it the voice coil was an important factor in the tone of the earlier ones?

Jeez, I have to do all of this now, Shakti?

Paper voice coils used through late 67, from what I've found, a few into early 68. The nomex and kapton versions came later in 68, but there were long transition periods (as in all things Marshall & Celestion I've discovered!). I find the paper voice coils have a little bit different tone than the later ones. I like it, and they had a little more "throatiness" that I liked.

From the 2005 shootout I did. The 20w pre rola G12M had the 102 003 cone, the M75 is a clone of the later 25w pre rola (mine from August 71), the Heritage 20w is Celestion's current version reissue of the original 20w.

Les Paul/65 Amps London (EF86, dual el84 amp)

Original 20w G12M pre rola: http://southbayampworks.com/stf/17scumclip.mp3" onclick="window.open(this.href);return false;
M75 25w Scumback: http://southbayampworks.com/stf/18scumclip.mp3" onclick="window.open(this.href);return false;
Heritage 20w G12M: http://southbayampworks.com/stf/15scumclip.mp3" onclick="window.open(this.href);return false;

Strat/65 Amps London (EF86, dual el84 amp)
Original 20w G12M pre rola: http://southbayampworks.com/stf/08scumclip.mp3" onclick="window.open(this.href);return false;
M75 25w Scumback: http://southbayampworks.com/stf/07scumclip.mp3" onclick="window.open(this.href);return false;
Heritage 20w G12M: http://southbayampworks.com/stf/10scumclip.mp3" onclick="window.open(this.href);return false;

Les Paul/69 50w Marshall

Original 20w G12M pre rola: http://southbayampworks.com/stf/24scumclip.mp3" onclick="window.open(this.href);return false;
M75 25w Scumback: http://southbayampworks.com/stf/23scumclip.mp3" onclick="window.open(this.href);return false;
Heritage 20w G12M: http://southbayampworks.com/stf/26scumclip.mp3" onclick="window.open(this.href);return false;

I remember those clips. Very interesting info, should explain a bit of that very gritty yet sweet, throaty tone that you hear on Fresh Cream and early Hendrix.

I'm saving my pennies already...

The first four M75 16 ohm paper voice coil prototypes arrive later today. I'll be doing comparison testing against my old 67 slant later. Tone report to follow.

Any updates on these, Jim?

Just to clarify - these are 20-watt voice coils? I assume so, but you don't say explicitly.

Any idea as to when they'll be available and what they'll cost?

Thank God- I thought you meant "plastic" when I read you said PVC speakers... I thought "he's gotta be kidding".

O.k. I get it. Duh.

Paper Voice Coil.

You gotta come up with a better acronym/Name for these speakers. Whew...!

Kevin wrote:Any updates on these, Jim? Just to clarify - these are 20-watt voice coils? I assume so, but you don't say explicitly. Any idea as to when they'll be available and what they'll cost?

The PVC models are going to be rated at 20w for M sized magnets and 25w for H sized magnets (G12M/M75, and G12H30/H75 speakers respectively). The actual voice coils are made out of the old technology Kraft paper, not the higher temperature versions used in my other speakers.

They will spark/burn/flame out if sent too much power, and will be sold with no warranty due to this. So if you have a 50w Marshall/Metro/clone amp, you'll get four of them, if you have a 100w you'll get 8 in two 4x12 cabs, just like the old days.

Updates...I've just completed the prototypes and have been banging on them all weekend with a buddy, then we switched over to my late 67 slant for comparison. The new models have a tiny bit more zing in the upper mids, meaning more cut/bite. The originals (since they're 44 years old) have a tiny bit more bass, not quite as much cut as the PVC versions. I'm sure that's due to age, and being more broken in. I am not going to FBI these speakers at all, so all of their break in has to happen as you play.

Right now the PVC M75 loaded cab is kicking ass on the M75 65w models with the 50w heads I have, which it should since the voice coils are getting more saturated than the 65w versions. Of course, I can't run it with a 100w head since they'd spark or flame out. I haven't built four more for a straight cab yet, as I'm still back ordered on previous sales, although I've caught up quite a bit.

Cost: $169 each, no FBI, plus shipping to your location. Availability, about an 8-10 day lead time as of right now with current flow or orders coming in (and that one of my production guys got that stomach flu that kept me in bed for 8 days).

chrisom wrote:Thank God- I thought you meant "plastic" when I read you said PVC speakers... I thought "he's gotta be kidding". O.k. I get it. Duh.

Paper Voice Coil.

You gotta come up with a better acronym/Name for these speakers. Whew...!

Considering they could get overheated, spark and burn...how do you feel about the name "Flamebacks"?

Great news! And, yes, "Flameback" is an awesome name.

Gonna start saving for these...

yes, flameback sounds nice. you need to destruction test these to see how much they handle.

Roe wrote:yes, flameback sounds nice. you need to destruction test these to see how much they handle.

Don't you already have some experience with melting voice coils? I could have sworn I read something like that on another forum recently...

Ok, here's the deal...voice coils are built to handle X amount of power, which is translated to heat where the voice coil is concerned.

When I asked for these "old technology" Kraft paper voice coils, my supplier warned me that nobody ordered these anymore since they could LITERALLY CATCH ON FIRE, SPARK or SMOLDER if sent too much power.

So I asked what the temperature melting point range was on my 65w coils, and what these were. The PVC coils had slightly less than 1/2 the melting point of the 65w. So there you go, gents....to be on the safe side I've given them a maximum rating of 25w.

This is also why they'll be sold without a warranty, due to the low power, low melting point of the paper coil.

So if you think you can "push them" a little harder and get away with it, think again...and have a fire extinguisher handy.

Congrats , Jimmy. But, you GOTTA do a destructive test. I wanna see a video of the speakers literally going up in flames. After all if you're gonna call 'em Flamebacks you better prove it!

How about a bunch of us throw in a few bucks to pay for a test subject? 17 people at $10 bucks a pop. There might only be a few of us with these pyromaniacal desires, though...

Kevin wrote:How about a bunch of us throw in a few bucks to pay for a test subject? 17 people at $10 bucks a pop. There might only be a few of us with these pyromaniacal desires, though...

Might be fun! Got to catch it on video.
Maybe have two cabs with a pair of Metro-Friedman heads in stereo (one a broken in cab of scumbacks which will keep running and another with paper coils , 'guest' guitarist pushing them to destruction so the cab burns whilst the other keeps running for the Youtube video, worth $10 of my money anytime if done properly