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Posted: Sat Oct 09, 2010 9:48 am
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BMW2002Ti wrote:
Thanks for the tip on Sozo caps. Is there any issues using them in places where there are usually 600 VDC rated coupling caps? The only site I found displayed 400 VDC rated products.

Thanks!


http://www.sozoamplification.com/purchaseBM.html


No problem as long as you don't exceed the voltage rating of the particular area of the circuit. Leo used to be very selective about the voltage ratings in his amps, using 200v where he could, 400 volts where there was the need for the headroom. 600v replacement caps got to be common later on. I read somewhere there can be a tonal difference in voltage ratings but I've never experimented with them enough to know for sure.


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Posted: Sat Oct 09, 2010 9:57 am
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Retroverbial wrote:
SoK1966 wrote:
And what color is that gorgeous "sparkle-finish" Tele? Looks very groovy!

Arjay


Thanks. I should update that picture, it has since been updated with a real '68 Tele body finished in sparkle silver by Marty Bell. That is an original sparkle silver '68 Tele that I hacked over the years. I've restored it to its original state using as many parts as possible from the original guitar, supplemented with real '68 Tele bits off auctions. The original body got stripped, hacked & butchered years ago and I finally gave it away. When I first did the resto I used a custom ordered Warmoth body, but decided that wouldn't do. I found a refinished '68 body on Ebay from the same '68 date range as the original. Marty stripped it and refinished it in his trademark sparkle silver, which is very close to what we remember of the original. It looks fabulous and sounds killer. Cost a lot to bring it back, which is what I get for having butchered it in the first place.


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Posted: Sat Oct 09, 2010 10:58 am
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SoK1966 wrote:
Cost a lot to bring it back, which is what I get for having butchered it in the first place.


Like the song goes......

"The things we do for love"

:mrgreen:

(BT-DT-GTTS)

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Posted: Mon Oct 11, 2010 12:17 pm
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Thanks for the replies,I've been off in the Smoky mountains trying to catch a trout...no luck this trip,but it was beautiful weather and my head got cleared out from work B/S.
The Super sounds great,but is going to get a set of new speakers.The orange caps are Mallory's !...415s or something like that,I like the 150s in my limited experience...those blue caps even look interesting....thanks for turning us on to them, SoK1966,you sound very knowledgeable about the Browns,the only other Brown I have is a '62 Princeton,I've always had the BFs and a Tweed Champ way back when.
Do you think it would be worth it to find a Super PT? or maybe a Mercury or other replacement?


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Posted: Mon Oct 11, 2010 2:24 pm
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Rebelsoul wrote:
Do you think it would be worth it to find a Super PT? or maybe a Mercury or other replacement?


Yes, absolutely. The early brown Supers used the same 8087 PT as the tweed Bassman, Bandmaster, Pro & Super. The part number changed later on, but the specs remained roughly the same. Yours would have had the 8087. These can be a bear to find used, so I'd save myself the hassle and get a good Heyboer/Mojo or Mercury replacement. Specify one that is "voltage compensated" to render the correct B+ & plate voltage at today's line (wall) voltage.

FWIW, my brown Super is a November '60 (JK). It has the 8087 and with a GZ34 rectifier at todays line voltages it will run pretty high B+ / plate voltage. I use a "buck transformer" called the Amp Preserver to lower the line voltage closer to the 117vac the amp was designed to see. It runs right at 445vdc at that line voltage, right on spec. and allows me to run NOS Tung Sol 5881 power tubes if I care to. Right now I have a set of NOS GE 6L6GCs in it and it sounds tremendous. Like yours, mine is a hybrid, with a later component board and six preamp tubes, the "-A" vibrato section, but the preamp component values of the earlier 5 & 6G4 Supers. Has maroon grille cloth with the 1960 "pinkish" brown tolex. I've had it for nearly 20 years and have never been able to find a set of original Jensen P10Rs for it. When I found it someone had installed a set of '60s Oxford 10s in it out of a Super Reverb. I tried the reissue Jensen P10Qs and didn't like them at all in that amp. I had some Kendrick 10s in it for awhile, but came across a pair of '61 Oxford alnico 10s out of a '61 Super. Close enough, said I and in they went.

As for the caps, the yellow Astrons that occasionally show up on Ebay are usually shot. Unfortunately, these days most of the ones I test in tweed or brown/blonde amps are either drifted way off or leaking DC so badly the amp sounds horrible. I hate replacing them, they just look right inside those amps. But, if I have to I'll generally use the Mallory 150s, which seem closest to the Astron to my ears. I have also done one '61 brown amp in blue moldeds. That was the year Fender transitioned from Astron caps to the Ajax blues and you'll often find amps that have a mix of them. If you watch the Ebay auctions blue moldeds come up all the time and I've yet to get a bad one. I do like the Sozos and am hoping someone uses the new blue ones in a kit build or refurb and tells us how they sound.


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Posted: Tue Oct 12, 2010 5:15 am
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Thank you for the info,my other vintage amps are BF except one Brown Princeton and I have been wanting one with 2x10s,the only tweed Super for sale I've seen lately was at Guitar Center and the price is $7400 !!
This Super came up for sale in a town close by and the guy was a studio player...man did he have some amps and guitars!
Anyway,the speakers are crap,replacements of some sort but they just don't cut it,I'm a Weber guy I guess because that's what I've wound up installing in my other amps.
The yellow Astrons do look cool in the amp,I hate to replace them but will if they don't check out,since the guy who had replaced the others was supposedly a tech they might still be good,but I have a feeling he was going for more headroom,hence the ss recto,and orange Mallorys which I've not had before,the amp does have more clean headroom than I would figure a brown Super would.
I'm not a tech but I've been learning about the insides of the amps in the last 10 years or so,and can replace caps and other things,but the PT is a new one for me,so I'll look for a replacement like you mentioned and get with my tech and go over the circuits and see what we can do with this baby....oh yeah,my wall voltage usually runs around 123vac at home and that's fairly normal,here at least,I work for the utility that distributes the power and we see it in that range mostly.


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Posted: Tue Oct 12, 2010 6:04 am
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That's about what our line voltage is around here. Most tube rectified vintage Fenders (pre-72 or so) will run about 25-30 volts over spec at that level. The trouble usually comes from the solid state rectified amps,like brown Bandmasters, which will run over 500vdc B+. These really benefit from a buck transformer, or a PT change.

Just looking at the pics of your amp again. The Astrons that were replaced were probably .05s based upon the 6G4 schematic and what we see in 1960 Super variant circuits, most of which were never documented. I'd look into having the remaining electrolytic caps replaced, particularly the filters and bias caps. You can add a bias trim pot when you do the bias caps, too.


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Posted: Tue Oct 12, 2010 10:26 am
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The guy who works on my amps,well he does the serious stuff,stopped by today and we talked about what to do....he's going to change the filter and bias caps,and he has some transformers on hand,and he will see if he has one that will work for this amp,and change it back to the tube rectifier.
I hadn't thought about adding a bias pot,I'll talk to him about that,since I like to bias my BF amps.
We're also changing the ODs to Mallory 150s,since I like the way they seem to sound.....I had wondered what the values were for the replaced Astrons.....thanks.
Was there ever a schematic for the 5G4? It seems that everything I've read says nobody has found anything....but now since you have helped,this is not a 5G4....right?..I'm still somewhat confused about the variants.


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Posted: Tue Oct 12, 2010 10:42 am
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Rebelsoul wrote:
Was there ever a schematic for the 5G4? It seems that everything I've read says nobody has found anything....but now since you have helped,this is not a 5G4....right?..I'm still somewhat confused about the variants.


Fifty years after the fact we're still treading in uncharted territory, it would seem. Many of the browns from the first production runs were never correctly documented, even by the original design team. I spoke recently with an acquaintance who's a big fan of the Vibrasonic and he told me that among the two dozen or so that he's examined or owned, no two of those amps from the first year of production (1960) matched one another completely in terms of circuit layout. Amazing!

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Posted: Tue Oct 12, 2010 10:46 am
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The 5g4s are basically identical to the 6G4s. Yours, like mine, is a transition circuit. It has the six preamp tubes and the component board of a 6G4-A, but the preamp appears to have 5 & 6g4 component values. Yours has many additional caps on the controls. None of that was ever documented on a schematic that I know of.

You can install a bias pot very unobtrusively by putting a 50k ceramic trim pot in series with a 10k or 15k resistor, in place of the 56k bias resistor between the bias caps. In mine some dope soldered a guitar pot between the board and the bias board, which didn't work right and put the whole amp at risk. Left a mess of solder on the chassis, but fortunately no holes were drilled in the chassis. These use the same bias circuit as a tweed Bassman, high power Twin or Tremolux. The brown/blonde Pro differed from the Bandmaster, Concert & Super in that it used the single bias cap circuit that would become std in the BF amps.


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Posted: Tue Oct 12, 2010 12:09 pm
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I like the bias pot suggestion.
Thanks for the comments guys,that's one thing I love so much about the old Fenders,the history,and even though some components have been changed,it still has that aura that maybe,just maybe,Leo could have walked into the area and poked his nose into it for a moment.....crazy I know,but I think y'all understand. :wink:


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Posted: Tue Oct 12, 2010 1:08 pm
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Rebelsoul wrote:
just maybe,Leo could have walked into the area and poked his nose into it for a moment.....crazy I know,but I think y'all understand. :wink:


Indeed!

I don't have anything from the pre-CBS era but everytime I plug into my '65 Princeton Reverb or my '66 Dual Showman I like to think that Forrest White, Don Randall, or Bill Carson watched -- coffee cup in hand -- as the warehouse guys in Fullerton stuffed the amp into the shipping carton to begin its ultimate journey to me.

:mrgreen:

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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