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Magnatone Maestro 150 amp

Posted: 23 May 2000 9:05 am
by Sutton Reid
Hi,

I'm new here and am not really a steel player except that a friend of mine asked me if I wanted a "Hawaiian guitar". I've learned that you always answer such questions "yes" and figure out the details later.

To my surprise, the gift included this amp. After taking it apart and cleaning it, it seems to work well, except that it runs quite hot. I play it with a Strat and really like the amp.

I've been able to determine that it was made in the middle to late fifties and has 34 watts. This would suggest to me that it is Class A operation, given 2 5881 output tubes. It also has a Jensen alnico 15".

Any info or advice on this would be appreciated.

I also got a lap steel as part of the package, an 8 string with one pickup. I don't really know what to make of it. Does anyone know if Magna also made a lap steel guitar? One of my things to do now is to learn how to play it.

Thanks in advance, Sutton

PS - This is one of the nicest sites I have found on the WWW. Actually, I should say what appears to be one of the nicest groups of people.

Posted: 23 May 2000 12:16 pm
by Tele
check here:

www.teleport.com/~vibroman/magnatone/index.html

I think you will find all the information you'll need
Have fun
Andy



------------------
1953 Fender Dual Professional
1962 Sho~Bud D-10
1970 Sho~Bud D-10 Professional
1954 Fender Super Amp
1959 Twin



Posted: 23 May 2000 1:17 pm
by Rich Paton
You scored! I've always wanted a Magnatone amp, super tone. The Magna models with vibrato are the only true, pitch-shifting vibrato ever made, vs. the common tremelo designs (amplitude modulation of the signal).

The two 5881's would normally indicate a push-pull, class A-B output stage. 34 true watts out sounds very typical, for its type & vintage. But...with Magnatone, you never know. They were quite advanced, low-compromise, and often "over-the-top" designs.

If you think it's actually running too hot, have it checked for the proper bias setting. Those old USA-built 5881's
(are yours Tung-Sol's?) are quite pricey nowadays, but if operated at the correct B+ voltage and bias settings, might well last a lifetime. They were made to last forever, under the worst of conditions.

Excess heat is also very hard on the electronic components in such an old amp.

I traded an old computer last year, for a '62 Blonde Fender Bassman head with 18 years of continuous closet storage time on it. The 5881's in it tested fine, but I have some new
Groove Tubes 6L6's kicking around, so I swapped them out "for the heck of it".
I didn't like the tone at all with those, so they are back in a desk drawer, and the ancient 5881's are back in the amp.

BTW, Magnatone did make lap steels. I don't know about the 8 string type. I had a six-string model, $15 at a swap meet in 1976, with case, Mel Bay method book, & a brand new bar. It was made from one piece of mahogany, with a faux, bleached "white oak" finish. The "fretboard" markings were in the form of a decal on the "neck", and it used old Kluson open-geared tuners, a heavy aluminum nut, and a huge alnico pickup. The P/U was so hot & gnarly, it could shave the hair off of a striped ape at a dozen paces. It had an extremely clean, fat tone.

Like an idiot, no, ~AS~ an idiot, I sold it in 1988. <FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by Rich Paton on 23 May 2000 at 02:42 PM.]</p></FONT><FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by Rich Paton on 23 May 2000 at 02:48 PM.]</p></FONT>

Posted: 23 May 2000 1:28 pm
by Jon Light
Hey Sutton. Welcome. For the guitar, the No Peddlers section of this forum is for folks like you. The moderator, Brad Bechtel has this excellent site--
http://www.well.com/user/wellvis/gitinfo.html

where you can do some research. There are only a couple of Magnatone guitar photos there. Check ebay, search under "lap steel", and you may find a photo for identification purposes. If and when you want to try to make heads or tails of playing the instrument, you are at the right place for asking questions.

Posted: 23 May 2000 1:34 pm
by Sutton Reid
Thanks, guys!

I don't have the particulars in front of me, but all of the tubes are US made. I have one tube that is known to be bad. Someone had put a 12AU7 in the guitar preamp section. According to the tube chart on the inside, there should be 12AX7 in the guitar preamp and 12AT7 in the mike side. I swapped it out and it works well.

When I went inside and cleaned everything up, I didn't see where the bias was adjustable. I just assumed that it was a fixed bias design. Vibroman has a nice picture of the amp, but no schemos for it. Well, I guess if I want a schematic, I'm going to have to do it the hard way!

I cried in 1973 when I sold my old blackface twin, but this Maggy has made me forget about it.

Thanks, again.

Posted: 23 May 2000 2:01 pm
by Rich Paton
Sutton, a "fixed bias" design just means that
when you set the idling current of the output
tubes, you use two fixed resistors as a voltage divider, to provide the proper voltage on the output tubes' control grids. This is done versus using a more convenient potentiometer to accomplish the same function. I prefer a fixed design, it only takes a couple more minutes to set up, and is more reliable and "tamper-proof".