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212 HD 130 Writing on the inside of cab?

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George Jeffcott (mrrons)
Username: mrrons

Registered: 05-2011
Posted on Friday, May 20, 2011 - 10:18 am:   

Hi,
I've just become the proud "father" of an HD 130 212 and after reading many of the posts on this site I came to the conclusion that mine probably dates from between 1977 & 1980 due to the fact that it does not have the 12ax7 valve and that the name plates on the front are black on silver
After delving inside with a torch, like a demented contorsionist, I've managed to get the numbers from the transformers.... I don't know if these would yield a date or not... I remember dating an old Bassman 100 head from it's Schumacher transformers and wondered if the same was possible with a Music Man?
Does anyone know who made MM's transformers?

I know that the serial numbers for the amp itself might as well be in Swahili for all the help they are!... But I did find the same number written twice in yellow crayon on the inside of the cab and was wondering if anyone else has similar numbers wriiten inside their cabs?
The number "178" appears twice inside my cab. It's written on the inside of the front panel, (the one that the speakers are bolted to), and it is also written on the bottom panel, just behind the reverb tank.
I was rather hoping that "178" might mean January 1978 as that would sit nicely with the rest of the construction of the amp.
My amp has valves made by Sylvania, so they must be old!.. I think mine also has EV speakers (EVM 12L), as mine have no MM decal or date code and the magnets are HUGE!.... Yet it sounds wonderful.

My grill cloth has that "distressed" look, rather like a convent girl being meanaced by a tramp, but apart from that... I think the old girl is doing just fine!

Vital Statistics:
Serial Co06455
Chassis 2475 130 EX
Output Tranny 4-130 EIA606-907
Power Tranny 200-130-250 EIA 606-322

Any ideas or information concerning the above, (especially the yellow crayon numbers!),would be greatly appreciated - Many thanks...
Bill Traylor (bozzy369)
Username: bozzy369

Registered: 02-2008
Posted on Friday, May 20, 2011 - 10:39 pm:   

c=big 2 channel amp
O=130/150 watts
06455=it's series number(i'ts the 6,455th of the C model.
Bill Traylor (bozzy369)
Username: bozzy369

Registered: 02-2008
Posted on Friday, May 20, 2011 - 10:42 pm:   

now for the date,you could be right on the January 78 thing,most have a slash between the month and year and most are found inside the chasis.
George Jeffcott (mrrons)
Username: mrrons

Registered: 05-2011
Posted on Saturday, May 21, 2011 - 05:23 am:   

Cheers Bill.... I haven't been brave enough to take the chassis out of the cab yet...!
I've read that some of the circuit boards have test dates signed on them, but I'll probably resist the temptation to remove the chassis until it requires a repair, (hopefully never!).
The same goes for my valves.
They are Sylvania's, but I can't read the model number, (I'm presuming they're EL34's), due to the fact that the side of the tube with the number is facing the chassis and I don't want to disturb the valves or they're seats... "If it ain't broke don't fix it" appears to be my motto at the moment!
Any idea who made the transformers, or were they an in-house production?
Bill Traylor (bozzy369)
Username: bozzy369

Registered: 02-2008
Posted on Saturday, May 21, 2011 - 10:24 am:   

I'm not sure of who made the transformers but they are special,so much that alot of musicman amps went by the wayside because people were using the transformers in other amps(mostly fender I believe),they are now in production though companys like mercury magnetics,most on here have liked their stuff.
Mike Kaus (mm210)
Username: mm210

Registered: 05-2006
Posted on Saturday, May 21, 2011 - 02:20 pm:   

Those sylvanias should be 6CA7's actually. The El tubes are a euro sort substitute tha came in when they stopped producing good 6ca7's.
Christophe Le Crom (vignau)
Username: vignau

Registered: 08-2010
Posted on Monday, May 23, 2011 - 01:04 am:   

"The number "178" appears twice inside my cab. It's written on the inside of the front panel, (the one that the speakers are bolted to), and it is also written on the bottom panel, just behind the reverb tank".
I have exactly the same kind of writing at the same places on my 210HD130(in red, not in yellow), but in my case it's 64, so not sure this si something to do with building date
Bill Traylor (bozzy369)
Username: bozzy369

Registered: 02-2008
Posted on Monday, May 23, 2011 - 02:34 am:   

or possibly the sending overseas date?
George Jeffcott (mrrons)
Username: mrrons

Registered: 05-2011
Posted on Monday, May 23, 2011 - 06:23 am:   

Funny you should mention the "red" writing Christophe.... I too have something written in red on the bottom panel next to the yellow "178" number, unfortunately, the red writing goes under the reverb tank and can't be read... It's a conspiracy!!
Thanks for the info on the valves Mike... I knew Sylvania valves were both old & out of production, so I'm now wondering if these are possibly the originals as I also know that the amp was unused for many years.
Overseas dating?... That's possible as I'm in the South of England & my cab does have the "EX" suffix on the chassis number.
On a slightly different tack, what's the general opinion on grill cloth?... Should I keep my original, slightly mutilated cloth or go for the nearest match I can find?.. This may well be subjective, as I kind of like the road-worn (slightly knackered) look of it, but if I could find the correct MM cloth, I might well go for recovering it.... But would that de-value it in the eyes of the purist?.... Oooh... I can feel that can of worms opening!!
Christophe Le Crom (vignau)
Username: vignau

Registered: 08-2010
Posted on Monday, May 23, 2011 - 07:17 am:   

For the grille clothe, I had to change it because it was in so bad shape after my children operations when there were youger. I put a fender silverface clothe , not the one I am use to see in stock amps, the blue line are light blue, almost grey, and behind front. Result is very nice, close to original.
George Jeffcott (mrrons)
Username: mrrons

Registered: 05-2011
Posted on Saturday, May 28, 2011 - 03:34 am:   

Info on the transformers.
The transformers were made by Woodward Schumacher.
The first digits are the part numbers, then comes the 606 prefix, which is their identification mark (EIA).
Numbers after this are year and week codes.
My trannys are:
Output Tranny 4-130 EIA 606-907
Power Tranny 200-130-250 EIA 606-822

So my output tranny should be: February 1979.
And my power tranny should be: May 1978

Hope this helps...