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Author Topic: Polytone Taurus Elite amp low volume no schematic!  (Read 19518 times)

Kaz Kylheku

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #30 on: August 10, 2013, 01:06:32 AM »
sometimes i can hold a key down and the volume will jump up to full volume for a split second if i pick the right key to hold.

That sounds like it could be a problem with the keyboard (in addition to the amp problems). Do you have another amp with which the keyboard can be shown to behave itself?
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Roly

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #31 on: August 10, 2013, 10:27:16 AM »
Nope, nobody wins.

It's starting to look like the horror stories around the net are right, and one has to wonder about a company that is so careless of its good reputation.

JM remarked on the dubious internals, and it's in keeping with the saying that "you never find just one roach in a kitchen".

I am simply boggled by the claim that they refused to service a brand new amplifier that turned up faulty; but given that claim it should be said that it is possible that this particular amp has never worked correctly and has been doing the rounds.  Still, if you fix it it's a feather in your cap.
If you say theory and practice don't agree you haven't applied enough theory.

J M Fahey

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #32 on: August 10, 2013, 11:18:15 AM »
Polytone used to be a small but serious Company, but like many similar ones, based around *one* person, not a team.
If that person starts failing, for whatever reason, the Company may well go down the drain.
I long suspected Mrt Tony Gumina  (Mr Polytone) has passed away, and maybe a widow, or children who are not into Electronics ut something else, are trying to keep it running.
Just checked, Mr Gumina is still alive, but being 82 it's not that unlikely that he had some kind of health problem.
Hey!! Just being alive at 82 is already an accomplishment !!! :)
I imagine a small, Family type Company, being run and staffed by elderly, retirement age people.
Even their Web Site, up to a very short time ago, consisted of scanned (paper) Catalog pages !!!
And they had no EMail but you had to **Phone** them !!!

This particular amp, the "made for something else" PCBs, the weird "let's add something else to an already designed panel, wherever it may fit" stringly hints at "let's use some unused/unsold stuff lying around".
Pity, because the product used to be good, and the idea very innovative.
FWIW: http://www.polytoneamps.com/index.html

By the way, they *still* list phone and fax as only contact means  :o

Mr Tony Gumina himself in 1950 (do the Math):

EDWARDEFFECT1

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #33 on: August 10, 2013, 03:52:31 PM »
got a call from Polytone and a e-mail that said they were sending me a schematic usps.will let you all know if i get it. diane seemed to be very nice on my answering machine. seemed like a nice lady judging by her voice.I tested one of the regulators on the 1st preamp board and i got -15vdc.I didn't find the +15vdc yet. i powered up the amp and ran a chord from the Polytone send to a traynor 20 watt amps return and the volume is low.must be a preamp problem.i need to verify the output section the same way as the volume is lower than what i had previously.if i get the schematic. i can use my signal tracer and check the ic's ect for signal starting at the inputs...
« Last Edit: August 10, 2013, 03:53:58 PM by EDWARDEFFECT1 »

Roly

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #34 on: August 11, 2013, 01:43:43 AM »
Quote from: JMF
the weird "let's add something else to an already designed panel, wherever it may fit"

I sat here for some time initially looking at the control panel layout, scratching my head trying to figure out the signal flow, and why it seems to depart so radically (and confusingly) from convention.

Meanwhile @Ed, track down those power supplies - no amp can be expected to boogie if it doesn't have the right supplies.
If you say theory and practice don't agree you haven't applied enough theory.

phatt

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #35 on: August 11, 2013, 06:13:29 AM »
Something to consider,, This is likely NOT a guitar amp, it's a line input mixer Amplifier package ..
So if you are plugging in an electric guitar then don't expect it to be as loud as the average Mega Gain guitar Amp. 8|

If all controls work then I'd hazza guess the amp is working fine you just need a dedicated Axe preamp in front and all will be fine.

I own and use a keyboard mixer amp so I'm familiar with the not so gainy inputs.
Just quietly,,, lower gain Amps like this are far more versatile. :-X
Phil.

Kaz Kylheku

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #36 on: August 11, 2013, 10:37:58 AM »
i powered up the amp and ran a chord from the Polytone send to a traynor 20 watt amps return and the volume is low.

I'm afraid that no hard conclusion can be drawn from this type of thing. We would need some assurance that the line levels in the effect loops of the two amps are nominally supposed to be the same.

Jumping volume levels can be caused by worn or dirty potentiometers, due to the wiper making an intermittent contact with the resistive element.

The first thing to do is give the unit a thorough cleaning: pots, jacks, and any switch contacts that carry audio that you're able to reach with spray or swab.
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g1

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #37 on: August 11, 2013, 11:59:52 AM »
i powered up the amp and ran a chord from the Polytone send to a traynor 20 watt amps return and the volume is low.must be a preamp problem.i need to verify the output section the same way as the volume is lower than what i had previously.
  Verify the output section by running the send from the Traynor into the return of the Polytone.

EDWARDEFFECT1

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #38 on: August 14, 2013, 11:13:00 PM »
i am supposed to get a schematic from polytone from Diane. it is supposed to be in the mail.i tried the effects loop with my traynor 20 watt tube amp and got very low volume using the traynor as a preamp and the polytone as a power amp and also got low volume with the polytone as a preamp and the traynor as a power amp.the only thing i question is that the polytone has what is called a main out.is it a preamp out,speaker out,power amp out.need a manual that identifies what it is.maybe thats why i didn't get volume using the polytone as a power amp.as i hooked the traynor send  into the effects return of the polytone.i don't have the volume i had previously.i am guessing i might of not hooked up a connector before putting the two back boards on the amp again. i thought i plugged everthing in ,but now i/m not sure.i've lost my patience with this thing and i am going to wait till i get the schematic to renew my interest in this thing...Ed!!

EDWARDEFFECT1

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #39 on: September 21, 2013, 02:11:18 PM »
got the schematic from poly tone.i have to figure out how to downsize it.i found out that i have the - 15v supply ,but lost the +15v supply. if i touch the regulator it gets hot.something is loading it down.i have the +24volts at pin 1 of the pnp regulator.any suggestions on locating the short that is loading down the regulator.i only get .003volts going to the ic socket of the +15v.the -15v is present. i replaced the regulator and got the same results.now how to find the part that is shorted and loading down the circuit.Roly,enzo,and juan ,i am going to leave my e-mail adress.if you want a copy of the schematic i will send one to you (polytone taurus elite).i have the power supply and another print with everthing else.the only problem is the print and the circuit board numbers don't match as they use the same circuit board for all three channels,but it does allow you to go part by part thru the circuit.....edwardeffect1@yahoo.com....thanks...ed!!
« Last Edit: September 21, 2013, 07:24:08 PM by EDWARDEFFECT1 »

DrGonz78

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #40 on: September 21, 2013, 08:09:34 PM »
Here are the schematics for the Taurus Elite amp... Ed sent them over to post up here for convenience. Thnx Ed!
« Last Edit: September 21, 2013, 08:11:25 PM by DrGonz78 »
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Kaz Kylheku

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #41 on: September 21, 2013, 10:59:35 PM »
Don't overlook the possibility that what is loading the regulator down could be ... the regulator itself, due to being toast, with an internal short.
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DrGonz78

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #42 on: September 22, 2013, 02:26:56 AM »
Yeah sure the regulator could be the problem but I think Ed said that he had replaced the 78M15 part. In this case I would be checking zener diodes or resistors for shorts. ZD3-6 and all zeners need to be tested. Also, voltage check of the 24volts rails needs to be established as well.
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EDWARDEFFECT1

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #43 on: September 22, 2013, 07:56:44 AM »
thanks Dr Gonz for posting schematics.all diodes on the board with the 15v supply regulators test good with a diode test. both 24v supply rails are present.when i do the pinkie test on the regulators.the new regulator i installed is getting hot to the touch.something must be loading it down.getting .003v output from it.now how to find the shorted part that is doing this?i have tested all the capacitors with a capacitor meter and also checked across the leads of the caps on low ohms of my fluke for shorts and i haven't found anything.also tested a transitor on the board and it is good also.there is a trace cut near a opto- isolator.i believe it was done at the factory and it doesn't seem to be in the same part of the circuit as my problem.as the amp previously did work with this same condition.just didn't seem to have 130watts.previously i found 2 wires detached from the unit.a black wire on the regulator board and a purple wire in the reverb board. they have been repaired.that is all i have for now. open for any ideas for testing for the short.guess it could be on any of the board with the 15+v supply.thats alot of parts to check.might not be on the supply board ,but may be on another board in a later part of the circuit.tough to test do to layout of boards all sandwiched together vertically.
« Last Edit: September 22, 2013, 08:08:22 AM by EDWARDEFFECT1 »

DrGonz78

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Re: Polytone Taurus Elite amp low volume no schematic!
« Reply #44 on: September 22, 2013, 12:14:43 PM »
Is there a way to detach the power board wires that carry 15v rails to the other boards? I mean at least then we could test the voltage at the source just to make sure it is good. That way we can then start looking at opamps etc etc... Well then again... So far it sounds like the +/-15v rails are being bogged down by something upstream. Are any opamps getting hot in conjunction with the regulator getting hot?
« Last Edit: September 22, 2013, 12:16:36 PM by DrGonz78 »
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