I found this MusicMaster Bass amp today

[pchilson]

Hi,
Today I found this is an antiques flea market shop.
Who has an idea of how to tell the date of manufacture?

Click images to enlarge them

[pchilson]

More pics.

[pchilson]

Still more pics

[milocj]

It looks like the output transformer date is the 32nd week of 1972, and two of the capacitor codes that I can read are from 1973 and 1974 so it should fit that it's a mid to late 1974 amp.

I think they also made it with a 6V6 power tube instead of the 6AQ5s that your amp has but I can't remember when the switch happened.

[Tim Armstrong]

Since it has the Fender logo with no tail, it's from sometime between 1974-1982. The speaker code indicates the speaker is from 1974. It's probably from around 1974!

Cheers, Tim

[pchilson]

Well, thats two for '74. Anything in particular I can show you or you can tell me how to ID positivley?

Thanks

[Sidney Vicious]

Ditto on the dating - I had a couple of those 6aq5a models and prefer them to the 6v6 for simple funky quirkiness. Plus those tubes are cheap.

That's a good cabinet too - pine not particle board like the later ones. The speaker sucks and there are a couple of tune-ups you can do to make the circuit more guitar friendly. Check around this Forum.

One thing strikes me though - I've never seen the tailless logo and that orange thread grill cloth on a 6aq5a model. Wonder if swapped in?

Still a cool amp.

And the cab is a perfect fit for a Champ chassis.

Edit to add: I looked again at the grill and in some pics I don't see the orange so could be my monitor. If so likely original.

[pchilson]

A shot of the logo on my amp.
According to the ampwares page and this logo the amp should be '77-'82

Logo:
Grille mounted, raised, chrome & black script "Fender" w/ tail (70-76) or "Fender ®" w/o tail (77-82)

But also according to that page it should be a '70 to ? and not the ? to '82
(see pics of knobs in 2nd post above)

Knobs:
70-?: Chrome skirted w/ black "F" center, numbered 1 - 10
?-82: Black skirted w/ chrome center, numbered 1 - 10

Mystery?

[endzone]

I'm pretty sure there was No tail on the logo after '74. If you look at every other Silverface amp on Ampwares, they show the "tail-less" logo after '74. The Musicmaster Bass is the only one I saw that showed a logo with "tail" after '74. That makes me think there's a misprint. Just sayin'.

[zook]

That's one of the MMs that didn't come with a fuse. Wouldn't hurt to put one in. If you look a little towards center of the power cord you'll likely find an indentation with the fuse holder cutout shape.

Winnie

[Tim Armstrong]

Originally Posted by endzone

I'm pretty sure there was No tail on the logo after '74. If you look at every other Silverface amp on Ampwares, they show the "tail-less" logo after '74. The Musicmaster Bass is the only one I saw that showed a logo with "tail" after '74. That makes me think there's a misprint. Just sayin'.

Yeah, I noticed that too, in fact I posted the misprinted dates first, but that just didn't seem right, particularly with those tubes and the '74 date code on the speaker, so I went looking, figured it was wrong and edited my post...

Cheers, Tim

[pchilson]

I have learned it has a CTS speaker in it.

FENDER AMP SPEAKER CODES
This chart will identify the speaker brand used in your amp.
Fender used speakers manufactured by the following companies:

Altec-Lansing -#391
CTS - #137
Electro-Voice -#649
Eminence -#67
Jensen - #220
Oxford - #465
Rola -#285
Utah -#328
Jensen supplied all Fender speakers until approximately 1961.
Since 1962 Fender used speakers from all the above companies

In the pic the "026888" is the Fender part number. The "137" is the speaker brand code. The "7423" is a date code showing '74 week 23.

The second image is EIA codes taken, one from the OT, the other I can't remember but they are also indicating '74 with weeks 31 and 32 as milocj stated above.

EIA numbers taken from the transformers may help you to determine the date of production on amps that fall between the different dating schemes. These numbers always begin with "606", and are followed by three or four digits in various combinations. If three digits are present, the first digit would refer to the year i.e. ("7" would mean 1967). If four digits are present, the first two digits refer to the year i.e. ("66" would mean 1966). The last two digits would refer to the week of the year i.e. ("26" would mean the 26th week or approximately June). An example would be: EIA 606-4-21 would mean the 21st week of 1964.

I am now certain with your help and info from Superior Music that it is indeed a '74 version of the amp. I think endzone is probably correct in stating about the misprint on the logo info.

[pchilson]

A few more pics. The envelope with the owners manual and schematic was inside the bottom of the amp. What I was told was the previous owner was an older gentleman that was an auctioneer who used it for a mic amp. I don't know if he was the original owner or not but the envelope with manual and schematic in the bottom might suggest that. There were also two Realistic mics with some mic cord extensions included.

[Tim Armstrong]

Very, very cool find!

Cheers, Tim

[endzone]

OK, now you've gotta say how much......

[pchilson]

Some more pics.
I have to believe the tubes are the factory originals, I don't know this but is my suspicion.
Preamp tube - RCA (Gray plate?) 12AX7A - Made in USA

[pchilson]

Power tubes
Sylvania - 6AQ5A - Made in USA

[pchilson]

I have been cleaning up the who knows how many years of dust and dirt on the inside of the enclosure, the paint abrasions and duct tape adhesive on the tolex. Some Goof-Off and ArmorAll do wonderous work. There are a few areas, mostly on the bottom edges and corners where there is some ripping/tears to the tolex. Most of this could have been avoided if Fender had used corner protectors on the amp. It basically looks like some old guy dragging it in and out of his trunk or pickup for 25 years or so. Very minor blemishes to say the least.

[pchilson]

Ok, I have done some searching on the TDPRI about this amp and have been reading several threads that all seem to be around 3 to 5 years ago. Not much discussion currently. I must admit it takes a while for some of this information to sink in when the subject is new to me. In a nutshell, what other Fender amp does this amp most closely resemble in sound and feel. Given that this amp is 34 years old and I don't know how long its been "on the shelf" since last used, do I need to do caps or is this something that you'll know it when you see/hear it type of thing? I've never owned an old amp before.
Can someone point out to me what are the safest points to use to drain the caps on this amp? I can supply the schematic and close up internal pics if needed. I understand the dangers involved and have been inside tube amps before but don't know this one and a little guidance would help.

Thanks

[pchilson]

Hmm, have had the amp on for an extended period of time today. I sit an play for a bit then I'm off doing other things, thought it might be good to let 'er heat up. After around three hours I was hearing this hard to describe but it was a kind of a hiss almost like something boiling over kindofa sound. It was not a crackling sound at all. This was random almost like did you hear that? kind of a thing. Volume was sitting on maybe 3 when I noticed this although I don't think the volume level has anything to do with it. What could this be? Is this sign of needing caps done? Any of you guys with experience with old amps please chime in.

Thanks

[pchilson]

Originally Posted by endzone

OK, now you've gotta say how much......

I gave the guy $180 out the door.
Funny thing is I spotted this amp about a month and a half ago. It is this junk/antique/flea market place so crammed with stuff you can't see anything for the fact there is so much your eyes can't focus. Well, this amp was sitting up on the top of a tall display case with stuff in front, in back and stuff was hanging from the ceiling all around it. You'd have to see this place to believe it. If I hadn't swiveled my head in just the right direction at just the right time I never would have seen it and I wouldn't be writing this today. Well the guy had a price of $795 on it, I didn't know what it was by model name or anything. He offered it to me if I wanted it for $450. I told him I would need to research it to know what it was and all. I went back 3 weeks ago, it was still there. I offered the guy $175 for it. He scoffed stating he had a guy in earlier in the week that would give him $300 for it when he sold some of his other gear. I said good luck with that and left. I stopped in yesterday, it was still there. I offered $175 again, he countered $200, I said good luck and started to leave. He said $180, I said "tax included?", he said OK, I said wrap it up.

Now I just need some of the tech types here to give me some advice on it.

[Tim Armstrong]

Originally Posted by pchilson

Hmm, have had the amp on for an extended period of time today. I sit an play for a bit then I'm off doing other things, thought it might be good to let 'er heat up. After around three hours I was hearing this hard to describe but it was a kind of a hiss almost like something boiling over kindofa sound. It was not a crackling sound at all. This was random almost like did you hear that? kind of a thing. Volume was sitting on maybe 3 when I noticed this although I don't think the volume level has anything to do with it. What could this be? Is this sign of needing caps done? Any of you guys with experience with old amps please chime in.

Thanks

Sure could be. Could also be the tubes need replacing.

There are some really great amp techs in your area. I really like Bruce Collins at Mission Amps down in Thornton. A great