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Converted tube PAs

TM1

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Jun 27, 2003
Messages
8,182
Pretty cool! For years Pete Townsend's main Hi-Watt head was a P.A. head that he linked the channels together for more gain.
 

Big Al

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Apr 24, 2002
Messages
14,318
I've converted some old Stromberg Carlson PA heads for guitar and they just smoke most amps. HUGE heavy duty transformers, coke bottle 6L6GB's, octal preamp tubes and great tone. My favorite tube amps.
 

spidey

Active member
Joined
Nov 21, 2003
Messages
3,252
Leslie West used a pa head in the early days of Mountain. He cranked the channel gain and that's how he got his overdrive. Sounded killer.
Lots of guys have used old Marshall valve pa heads for guitar, which are very similar to the Super Leads .
 

callaway_1

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Joined
Dec 22, 2005
Messages
460
Pretty cool! For years Pete Townsend's main Hi-Watt head was a P.A. head that he linked the channels together for more gain.

I hate to correct you as I have learned a lot from your posts over the years, but Pete's amps were not PA heads.

These amps did have more in common with HIWATT PA heads than the DR103 all purpose amps, but they weren't PA heads or converted PA heads....at least not those that actually belonged to Pete. MG has sold several conversions as former WHO pieces, but that is a different story.
 
Y

yeti

Guest
These do the trick nicely and no need to convert:dude:

1966-pic1.jpg
 

Riffraff

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Joined
Jun 16, 2002
Messages
165
This one was in amazing condition when I got it. It was full of Sylvania glass that looked original. The 6L6GA's sound so nice clean. They are really soft sounding tubes. I put a pair of RCA 6L6GC black plates in the amp more out of concern for today's modern wall voltage pushing this higher than those tubes could handle. They sound great as well. Channels 1 and 2 are linked so they run together. Channel 1 is clean and deep, channel 2 is brighter with more gain. The mix of the two via their separate volume controls let's you dial in pretty much anything you want from dark & moody to bright & crisp to nice & crunchy with big bottom thump. I run it through a pair of '74 CTS alnicos that came out of an old Kustom Tuck & Roll cab. I built a deep pine 212 cab for those that fits the amp perfectly. They sound really nice and pair incredibly well with this amp. It's a fun blues rig. It's got great touch sensitivity and responds really well to pretty much everything. It's a great for riding your guitar's volume control on the edge of break up.

I love it's lead tone too:

https://www.youtube.com/watch?v=wWRFxCSSVjI
 
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Big Al

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Apr 24, 2002
Messages
14,318
This one was in amazing condition when I got it. It was full pf Sylvania glass that looked original. The 6L6GA's sound so nice clean. They are really soft sounding tubes. I put a pair of RCA 6L6GC black plates in the amp more out of concern for today's modern wall voltage pushing this higher than those tubes could handle. They sound great as well. Channels 1 and 2 are linked so they run together. Channel 1 is clean and deep, channel 2 is brighter with more gain. The mix of the two via their separate volume controls let's you dial in pretty much anything you want from dark & moody to bright & crisp to nice & crunchy with big bottom thump. I run it through a pair of '74 CTS alnicos that came out of an old Kustom Tuck & Roll cab. I built a deep pine 212 cab for those that fits the amp perfectly. They sound really nice and pair incredibly well with this amp. It's a fun blues rig. It's got great touch sensitivity and responds really well to pretty much everything. It's a great for riding your guitar's volume control on the edge of break up.

I love it's lead tone too:

https://www.youtube.com/watch?v=wWRFxCSSVjI

Yup, I think it is a shame how many completely miss the point of this thread. It's not ANY PA head it's old school,(literaly as that's what old schools), cathode biased true point to point wired tube amps in industrial metal cage heads. I find it interesting how many new amps cop that look now.
 

Bob Womack

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Apr 8, 2002
Messages
2,052
At the start of a recording session, Dickey Betts Arrived at the studio with a guitar but his amps didn't make it. He described plugging into a Bogen amp and wedge speakers hanging on the wall that were used as studio foldback and getting a great tone with that rig for the first song they recorded. The next day his amps arrived for the rest of the album. He mused that he wished he'd taken the Bogen rig with him.

Bob
 

Riffraff

Member
Joined
Jun 16, 2002
Messages
165
Yup, I think it is a shame how many completely miss the point of this thread. It's not ANY PA head it's old school,(literaly as that's what old schools), cathode biased true point to point wired tube amps in industrial metal cage heads. I find it interesting how many new amps cop that look now.

Exactly. That old tube PA that was used for classroom anouncements or "clean up in aisle 6" at the A&P for 30+ years are the ones that make great guitar amps, especially of they had at least two channels that could be joined. Some of these, like the Masco's, were overbuilt and made to provide reliable service for decades. Many of these were turned on and left on for years.

PICs

Under the hood:
http://i706.photobucket.com/albums/ww70/2266vm/MA50018_zps16456529.jpg

As purchased:
http://i706.photobucket.com/albums/ww70/2266vm/MA25Pgut1_zps7e3ceab4.jpg

Dog bone resistors, you don't see those often.
http://i706.photobucket.com/albums/ww70/2266vm/OldSchool_zpsb6a97da5.jpg

After it's tune up:
http://i706.photobucket.com/albums/ww70/2266vm/MA50015_zpse0b23d23.jpg
 
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chuckNC

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Joined
Apr 24, 2012
Messages
1,261
Chicago's Terry Kath was known to run a Bogen PA head through a Showman cab back in the day.
 

Mitchell

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Joined
Feb 20, 2002
Messages
3,012
This one was in amazing condition when I got it. It was full pf Sylvania glass that looked original. The 6L6GA's sound so nice clean. They are really soft sounding tubes. I put a pair of RCA 6L6GC black plates in the amp more out of concern for today's modern wall voltage pushing this higher than those tubes could handle.

Riffraff,, the main you need to do, if you haven't already, is to upgrade the filter caps asap, 500 or 600vdc.
Just going to GC's is not going to handle everything correctly, if you want to run todays fluctuating wall voltage.
Replace any major power resistors that are stock/original too.
Good choice on the speakers/cab, as they seem to prefer brighter sounding speakers.
Use a power conditioner, if you have one.
Then record us a stock sounding clip with no pedals, etc.

.... :yah
 

fender69

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Joined
Apr 17, 2003
Messages
987
Any tips on which ones to pursue? I'm in Chicago and there's probably tons of things like those floating around this town.

I've converted some old Stromberg Carlson PA heads for guitar and they just smoke most amps. HUGE heavy duty transformers, coke bottle 6L6GB's, octal preamp tubes and great tone. My favorite tube amps.
 

Riffraff

Member
Joined
Jun 16, 2002
Messages
165
This amp was done by Skip Simmons. The dude is the God Father of Masco conversions. All caps have been replaced. Those big filters were clipped and left in place to cover the holes but modern caps are installed below. Numerous resisters in key locations were checked for drift and voltages were checked all over. Surprisingly there wasn't a lot of drift so he left them alone. Skip comes from the school of less is more. He does vintage amps for a ton of pro players and studios so I left it in his very capable hands. He said he does most of them for harp players. Usually they are the smaller 8 & 10 amp units for guys looking for that authentic Chicago blues sound. Masco's in particular are their most sought after amps. He said every once in a while he gets a request for one done up for guitar. He said they are his favorite to do. I told him do this one up the way you like them. The amp got a clean bill of health and is ready for decades more service.

By the way, the Hotplate on top of the amp in some of the VIDs isn't hooked up, it's just sitting there.

I have a clip of a Les Paul straight in. The playing sucks but hey, what can I say....I blanked. :D
I'll try to get one together clean with my Strat. That sounds really good through this.

Anyway, here it is....just Lester:

https://www.youtube.com/watch?v=SIuTTY3uzOY

More dirt - Here is one with a Tele that starts with no pedals but I stomped on a SD-1 about 30 seconds in and let it rip. The dirty tone is less defined, sort of lofi with a single pole loaded Telecaster. Very different vibe. More Silvertone Twin 12 flavored than the Plexi-ish tone you get with a Les Paul.

https://www.youtube.com/watch?v=M2V_yZaAYSU
 
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Mitchell

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Joined
Feb 20, 2002
Messages
3,012
Luv it either waay,, thanks.
"Straight in" it really has some great touch sensitivity coming through... :yah
 

Big Al

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Apr 24, 2002
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14,318
Any tips on which ones to pursue? I'm in Chicago and there's probably tons of things like those floating around this town.

Masco, Bogen, Knight, Stromberg Carlson... The main thing for me is 6L6 power tubes, 6S7N's or similar preamp tubes. Those fat octal preamp tubes are key to the magic in feel and tone. Watch out for oddball tubes, (Bogens in particular).

Make sure it is the PA type and not an intregated amp. You'll have to replace the mic inputs with 1/4 phone jacks and Ilike to change to the same for spkr outs. Don't forget the three prong plug.

You can find working nice examples for a few hundred bucks.
 

straightblues

Member
Joined
Mar 17, 2004
Messages
954
I have a couple of Bogen pa amps converted over for guitar use. I had the preamps totally rewired to Fender Harvard specs. They sound just like a sweet vintage tweed fenders. Great transformers. I love them. I would put these amps up against anything, at any price! There tone is that good.
 
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