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 on: Today at 04:22:53 PM 
Started by jerryb - Last post by jerryb

Thank you for all that information, although I must admit, I'm not an electronics guy so most of what you said was over my head.

If I understood you correctly, your link to the schematic for the Taurus Elite (I see the the middle and right image scans on the other forum) will apply to my Taurus II?

If I provide the entire 3 pages of that schematic to the amp technician, will he be able to work from it?

 on: Today at 05:28:10 AM 
Started by jerryb - Last post by teemuk
Polytone amps were designed very modularly: They featured power amp modules, which were subject to design changes since the beginning. For example, you can likely find a handful of “378” power amp designs. Few are discrete; few have an integrated driver chip, which is now obsolete.

Once in a while they made a preamp design packed with features, which then went to the “flagship” model mostly as is. Other models were then derived from that design, largely by stripping off unnecessary features. This is no different from what other manufacturers were doing as well. For example, “Lead” model could include two channels, fuzz or distortion, reverb and perhaps a vibrato function of some sort. For “Bass” model the design was identical except for stripping away one channel, reverb, fuzz/distortion and vibrato as unnecessary features not implemented.

Therefore Polytone schematics were often just titled “Preamp” and notes were included to describe what parts of the portrayed circuitry various preamps of different amp models actually contained.

For example, this preamp schematic applies to Mini Brute models 1 – 4, Brute models 1 – 3, and Mega Brute and Mega Brain models.

All in single schematic. Ignore parts that simply were not fitted.

Note that this was for ‘90’s Brutes. Polytone also made Brute series in the late 1970’s simply by stripping certain features away from their former “Lead & Bass” preamp design. With some searching you can find a pre ’77 schematic titled ”Lead & Bass” and an identical schematic from 1977 titled Lead / Bass / Mini-Brute. The latter describes what sections of the circuitry are used for MB models 1, 2, 3 and 4.

For that reason, with Polytone schematics, make sure you have the period correct! They sure loved to recycle model names.

Here’s partial snippet of Taurus series preamp:
(You can find rest of the schematic from Music Electronics Forum*)
This applies to Taurus models, I, II, III and Elite. Taurus I was a single channel amp with most of the portrayed features stripped, Taurus II and III were dual channel amps. Depending on model, “Midrange” and “Distortion” controls were implemented to other controls using dual potentiometers.
“Elite” was a three-channel amp and if you refer to schematic notes (the schematic IS NOT just for Elite model) channel 3 was same as channel 2 and the circuitry involving distortion feature was omitted from "Elite". Also, not all Taurus models featured the rotating cabinet simulator titled “Modulator”. 212 versions of these amps were only ones with the portrayed X-over.

AFAIK, all Polytone amps – except Fusion – are built this way. Fusion is an exception since it wasn’t a solid-state amp.

I hope this answered your query.

*Link to "Polytone Schematics" -thread here:
Do also check out and for more Polytone schematics.

 on: June 24, 2017, 02:09:02 AM 
Started by galaxiex - Last post by galaxiex
Cool.  8)

Thanks Enzo.

Hopefully when the new O/T gets here, it will have something to ID the leads.

Edit; Oh... yes it does...  I ordered this one...

 on: June 23, 2017, 11:13:46 PM 
Started by galaxiex - Last post by Enzo
Phasing really only matters when the same signal is fed to multiple amps.

There appears to be no negative feedback loop, so phasing doesn;t matter there either.

usually output transformers identify hot and cold lead by color.  SO good practice would be the cold side to chassis.

 on: June 23, 2017, 10:29:42 PM 
Started by galaxiex - Last post by galaxiex
Sooooo, as per the schematic attached above, the original O/T secondary went straight to the speaker.
No connection to the chassis.

Since I am installing a speaker jack,
I have the option of installing an insulated jack that obviously, would also not make any connection to the chassis.

If I were to install a non-insulated jack, would it then make some difference as to which side of the secondary should be connected to the ground side of the jack?
IOW, is there a phasing issue that I need to be concerned about?


 on: June 23, 2017, 08:28:43 PM 
Started by jerryb - Last post by Enzo
No help, but also try here:

 on: June 23, 2017, 05:46:04 PM 
Started by jerryb - Last post by jerryb
Hello, someone from another forum suggested I ask here. I'm searching for a schematic for a Polytone Taurus II
Does anyone here have one? I checked two other sites that sell schematics and they didn't have it.

Here is what one looks like:

Thank you!!

 on: June 23, 2017, 05:44:25 PM 
Started by solidstate2199 - Last post by Enzo
Or cut the dust dome off a dead speaker and glue it to a stick.

 on: June 23, 2017, 12:10:22 PM 
Started by solidstate2199 - Last post by solidstate2199
Thanks for the tip Enzo, :dbtu:

i will try the oldschool duct tape trick or
McGyver me some beamblockers.

 on: June 23, 2017, 12:03:48 PM 
Started by solidstate2199 - Last post by Enzo
That is why they make "beam blockers".

Easy to install, and they are effective at spreading the sound and killing that ray-gun beam straight out the front.

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