Versatone Pan-O-Flex

[CJ]

searched the usual suspects for a circuit diagram of the Versatone Pan-O-Flex,

no luck

this is an obscure bi-amp affair with a 12 and 8 inch speaker

used by Jack Cassidy and Carol Kaye

supposed to have some serious mojo

thanks for any help! 

 

[stoya]

Voila CJ

 

[pucho812]

maybe we should add to the schematics collection. I met Carol Kaye last year when she was touring the work place. She  had lunch with us which happened to be BBQ day that day.  She is one hell of a player bass or guitar.

 

[CJ]

WOW!  A Million Thanks!  Thought the thread was dead like fred.

 

[CJ]

ok i redrew the schematic, there might be a few resistors that are off because they were hard to read, but i think everything is pretty close,

left off the Casady mods, and drew the speakers without the 5 pin jack as it was very confusing,

this amp uses an 8 inch and 12 inch speaker, do not know if the Utah spk numbers are correct so i left them out, looks like they added line outs for a power amp, possibly a big Macintosh amp for stage use since this guy is only good for about 30 watts,

it uses 7591 power tubes, which were used in some Fischer stereo amps,

looks like they have a pi filter on the bass speaker,
calculations for a
50 uf - 14 mH - 50 uf
pi filter look is 270 hz is the center frequency, phase angle will be 180 degrees at this freq if i have the filter right,

looks like Casady's amp was modified to combine both channels into the 12 inch only, he probably blew up the 8 inch,

here is the schematic, let me know if you spot any errors, have not built the amp yet so schematic is not verified>

 

[CJ]

at the bottom are  some shots of the speaker cab and chassis that i lifted off the web,

notice that the output transformers are different, the 8 inch spk xfmr is smaller than the 12 inch xfmr, this is because it does not have to handle as much powere as bass really uses the watts,

smaller means better high freqs due to reduced Capacitance,

used for guitar>

http://www.youtube.com/watch?v=SqZspx3ebzI

this the site with the schematic>

http://www.talkbass.com/forum/f15/versatone-pan-o-flex-copies-they-there-926609/

page 2 with chassis shots that i lifted>

http://www.talkbass.com/forum/f15/versatone-pan-o-flex-copies-they-there-926609/index2.html

wiki>

http://en.wikipedia.org/wiki/Versatone

bass being played thru the Versatone>

http://www.youtube.com/watch?v=E_k5ZOuJrh0

Hot Tuna with Casady using the Pan O Flex>

http://www.youtube.com/watch?v=mjfhsLuOEWI

uses 2 can type caps for pwr supply filters, one one the right near the pwr trans, and one on the left by the preamp,

pi filter caps are those big silver guys on the middle board,

pi filter inductor is mounted inside the chassis, looks like a choke coil,

 

[PRR]

7591 tubes in Treble channel will be much happier with resistors from G1 to a bias supply.

Are you sure the 360K in Treb Cathodyne returns to the speaker? That can work, sure, and give bootstrapping, but not enuff to matter. Also not done on Bass side.

High-pass filter into Treble channel, 0.0047u+470K chain, seems to be 75Hz..... no wonder the poor Eight died.

That also casts doubt on the idea that the Treb carries less Power (strictly V/F) than Bass, since 75Hz includes most of the notes you would play through a Twelve. (However I wonder if the designer sat there with two similar amps and two speakers he liked in two different ways, and combobulated.)

1N4007 will work but are not sufficiently robust, IMHO, considering trash on the line, possible heavy use, and the low cost of 1,600V 2.5A diodes.

I'd put 1Meg-3Meg on the input jack to ground. The plan shown will work for all passive guitars but maybe only 99% of active stuff (guitar or pedals).

 

[CJ]

good eye on the bias resistors PRR!

schematic fixed and 1 Megs added,

8 inch speakers can be pretty solid for bass these days, but the old Utah stuff was sure to get cooked by Casady who probably had a stomp box of some kind  in front of the amp back then,

he used to put the amp in a hall, mic it, and then  bleed some of the signal back  in with his other amps for some songs like Crown of Creation by JA.

people say the amp has a cross over but it is really just a split  off the bass and treble controls,

also, the  speaker cab has a hole drilled for blending the air between the 2 speakers,

 

[desol]

The thing sounds killer. Lots of nice sag (?) and compression to the sound....
Beauty

 

[tubegeek]

I saw Hot F'ing Tuna back in the day, late '70's, outdoors in the Berkshires (Massachusetts, not England.)

Oh My God, were they loud! Seriously.

Great band. Cool amp, thanks!

 

[PRR]

In the mid-1970s, their Rampage Years, I was walking toward a Hot Tuna show. I had been with a basement band the night before and my ears were still seriously ringing. I stopped in the parking lot, 200 feet and a steel wall away from Tuna, enjoyed a song, and walked away. I miss not seeing Jack live but going in there was more than my ears would bear.

In the 1980s, my partner and I scored gigs doing PA for Ella Fitzgerald +and+ Hot Tuna on the same night. He drew the Tuna gig. They were considerably downsized by then. I don't think we owned 500 Watts and I wudda took 100W for Ella. (Fat hollow-state Watts, not the skinny silicon watts.)

 

[tubegeek]

500 watts wouldn't have lit the pilot lights when I saw them.