Polytone in a Pedal

[Frank67]

maybe the polytone preamp would just be the layer you put before your DI, in order to get a classic jazz tone

I think that the appeal of the pedal would be to be able to have that classic Jazz tone in a small package and be able to go direct to the PA or into a recording device. XLR is helpful in this respect but most PA systems also accept regular connectors.

In my mind adding a cab sim and reverb ist not strictly necessary since peoples preferences vary so much. Sure, if you have a setup that invokes just one pedal and your guitar that is nice. But most people, I guess, would want their own choice of reverb and possibly their own choice of cab sim.

In my opinion, most simple cabsims are strongly underdelivering compared to good ones and hence the urge to put something like the torpedo cab after it would probably still be there (plus the power amp sim that is an important component of the sound, but perhaps less so when modeling a solid state amp). Hence, unless one can load a commercial (or non-commercial) IR into the device (which will add to complexity, perhaps size and price of the pedal), I'd rather keep it simple and have the pedal being one component in a tailored signal chain that is just there to deliver that nice, warm, lush, signature jazz tone.

I personally would not look for any kind of overdrive in this pedal. The original polytone overdrive sounds terrible and if I want to have an overdriven tone, I'd likely go for an emulation of a Marshall or Soldano or whatever amp or a clean amp with a nice overdrive or distortion pedal, but likely that clean amp would not be a polytone (although some people say good things about a polytone and a rat).

Looking forward to this pedal!

Good luck!

[lawson-stone]

I think I would enjoy having a reverb on the pedal, but it would not be deal-breaker if it didn't.

[add4]

Hello guys,

just a little update..
it's far from being mature ... and too large :'(, but it's a starting point

[add4]

I think you can easily see why adding reverb or cab sim might not be so easy .. at least not in a small box

[MilesPG]

Awesome!!! Let me know if you print the final PCB I'd buy one to build the preamp with the AMT IR loader and a digital reverb

[Herbie]

I think you can easily see why adding reverb or cab sim might not be so easy .. at least not in a small box

No cab sim, ok, but does it make espresso?

Seriously speaking, the Two Notes Torpedo cab sim is about twice this size and costs ~ 500€. If one could get the same quality just like that in DIY method, why would anyone pay for the real thing? It ain't a Klon!

And the Polytone is an old thing, a classic from '70s. Cab sims are contemporary thing that is developing all the time. The Torpedo is now the hot one, next year there is another hot one. But Polytone stays!

A pedal with a Polytone sound is a revolutionary thing alone. Thumbs up, add4!

[add4]

Awesome!!! Let me know if you print the final PCB I'd buy one to build the preamp with the AMT IR loader and a digital reverb

This is entirely possible of course. I can provide a BOM and the PCB, but probably won't be able to help a lot if you run into a problem building it, since i know how hard debugging a faulty build can be even with both hands on the PCB (don't ask me how i learned that... )

the voltages on the ICs will be pretty usual anyway, except that i'm using a charge pump in an unconventional way to get -9v/9v instead of the traditionnal 0/18v used in pedals. This is to keep the original polytone design on the preamp on which the opamp is biased around 0v, with a -15/15V swing, and not around 4,5V or 9v like traditionally done in pedals.

[add4]

No cab sim, ok, but does it make espresso?

Seriously speaking, the Two Notes Torpedo cab sim is about twice this size and costs ~ 500€. If one could get the same quality just like that in DIY method, why would anyone pay for the real thing? It ain't a Klon!

And the Polytone is an old thing, a classic from '70s. Cab sims are contemporary thing that is developing all the time. The Torpedo is now the hot one, next year there is another hot one. But Polytone stays!

A pedal with a Polytone sound is a revolutionary thing alone. Thumbs up, add4!

Thanks for the kind words .. it pretty much summarizes my point of view!

i have no merit in this, i'm merely adapting the preamp a bit to get it more 'pedal friendly', and also adding the gain knob... nothing really special or amazing.
The idea .. i've wanted to do that for a looong time since i miss my polytone everytime i play on anything else

i truly hope i can bring something useful for the jazz community, and also have the fun of making it happen, and i confess i'm proud everytime i hear someone using one of my pedals and getting great sounds.

[add4]

I think I would enjoy having a reverb on the pedal, but it would not be deal-breaker if it didn't.

that would be possible but on a larger box. the problem is always the same. you can get a great sounding reverb in a box, but the more you add into one box, the less flexible you are..
i can relate to the idea of taking just one pedal to a jam session and know you can plug into it, then into the PA, and sound good.. and reverb would definately be a part of it so i added it to the list of possible mods
in the end, we'll and up with a community driven jazz guitar preamp, a bit like the ethos clean but for jazzers
i'd love to be part of that story!

[Frank67]

That sounds awesome! I had an Ethos clean but I never bonded with it (it is now with Jorge). I would be all over your polytone pedal. Are you planning to add a Bright/Dark/Neutral switch? That might come in handy.


Cheers,
Frank

[add4]

That sounds awesome! I had an Ethos clean but I never bonded with it (it is now with Jorge). I would be all over your polytone pedal. Are you planning to add a Bright/Dark/Neutral switch? That might come in handy.


Cheers,
Frank

The bright/neutral/dark switch is on the design. i don't know if you can see the pictures of the PCB and the mockup (for some reason they don't appear on my computer, but they are on my phone.. ) but the switch is there, i called it 'voice'.

I could add another switch for the tighter low end, but i'm not really sure where to put it .. i might need to sacrifice the gain knob, which is not in the preamp in the first place, but i think it could be a great addition..

choices choices

[Frank67]

A tighter bass or low cut filter may be important to deal with boominess - that is notorious problem with archtops and just turning down the bass makes everything sounding thin.

sounds like a fun project!

[lawson-stone]

that would be possible but on a larger box. the problem is always the same. you can get a great sounding reverb in a box, but the more you add into one box, the less flexible you are..
i can relate to the idea of taking just one pedal to a jam session and know you can plug into it, then into the PA, and sound good.. and reverb would definately be a part of it so i added it to the list of possible mods
in the end, we'll and up with a community driven jazz guitar preamp, a bit like the ethos clean but for jazzers
i'd love to be part of that story!

If you just put the Polytone pre-amp and Polytone-like controls on it, I think you'll have a winner. Any of us who use it to play through a PA likely won't need reverb because PA's are in rooms, and rooms provide a natural reverb. Just having the Polytone magic in a little box in my guitar case or kit bag... that'd be wonderful.

[lawson-stone]

I had one thought.... often the criticism made against ES175 copies is that they try to improve on the ES175. I hope you'd consider NOT trying to improve on the Polytone. People who like Polytones generally like them pretty much as they are. I personally don't want the pre-amp improved, sound wise. Extras like an auxiliary input or XLR out would be nice, but the sound itself (for me, that is, not necessarily others) should be authentic Polytone.

[add4]

If you just put the Polytone pre-amp and Polytone-like controls on it, I think you'll have a winner. Any of us who use it to play through a PA likely won't need reverb because PA's are in rooms, and rooms provide a natural reverb. Just having the Polytone magic in a little box in my guitar case or kit bag... that'd be wonderful.

well it will be different from a polytone ... and the same thing also..

because by design, the polytone preamp can be transparent (switch to normal, bass/medium/treble at noon). Then the EQ is dead flat, and you basically hear your guitar through the power amp and cab/loudspeaker.
In that position, if i plug the pedal into my fender i hear ... my fender , no difference.
so, that means that you will have the sound of the PA, power amp, cabinet, preamp, ... whatever chain you're plugging into. and it will sound different from a polytone cab and speaker.

But, once your start using the EQ and the switch, you are enhancing the polytones frequencies, in a way that only the polytones do. and you can actually correct the amp you're using to get a very polytoneish sound.
from my experience it will be useful to corret all preamp related voicing problems.
What you will not be able to correct will be the power amp problems (tube sag, compression, lack of dynamics, ...) the polytone power amp have a LOT of headroom and reat REALLY fast so the attack is ultra clean, fast and dynamic... that will still depend of the power amp you plug into.

To summarize, i am certain that you can get polytoneish sounds with the preamp but not at the same settings at the ones of a real polytone because you will probably be correcting something. the flatter and cleaner the platform you plug into, the closer you will be to a real polytone sound. But i am confident that you can make a fender sound at 95% like a polytone.
The dynamics and reaction, 'directness' of the sound will still depend of your power amp and speaker.

i hope that makes it clear so everyone who actually decides to get one in the end knows the pro and cons

[Nils]

Count me in! This sounds like a really cool pedal, and I agree - keep it simple and let it do its thing...

[Little Jay]

I think it will be a pretty ideal pedal to use to go directly into the power amp of my AER Alpha (it's preamp is voiced for acoustic guitar, I can get good useful tones with my ES-125 but with pretty extreme settings), maybe even with my Boss FRV-1 reverb (pretty good spring reverb emulation!) after it. The power-amp of the AER is also really fast and the closed-cabinet is pretty Polyfone-ish, so I have high hopes it will do a pretty good Polytone-like tone. Can't wait......

[add4]

I had one thought.... often the criticism made against ES175 copies is that they try to improve on the ES175. I hope you'd consider NOT trying to improve on the Polytone. People who like Polytones generally like them pretty much as they are. I personally don't want the pre-amp improved, sound wise. Extras like an auxiliary input or XLR out would be nice, but the sound itself (for me, that is, not necessarily others) should be authentic Polytone.

at the moment i'm making one change, that is virtually without impact: this things has tons of available volume, so i'm adding a gain knob which would be 100% clean for the first half of the course of the pot, and then start to ... not even crunch, more like purr, just adding a bit of harmonics.. it's actually an adaptation of the gain stage of the RC booster so if you konw that pedal or look at demos, you can have an idea of how clean it stays even when the gain maxed out.
I am proposing this because most people who have a RC booster actually love that gain knob. but i could also remove that (and have more space for the tight low end switch).
But i think it would be a neat improvement.

[add4]

I think it will be a pretty ideal pedal to use to go directly into the power amp of my AER Alpha (it's preamp is voiced for acoustic guitar, I can get good useful tones with my ES-125 but with pretty extreme settings), maybe even with my Boss FRV-1 reverb (pretty good spring reverb emulation!) after it. The power-amp of the AER is also really fast and the closed-cabinet is pretty Polyfone-ish, so I have high hopes it will do a pretty good Polytone-like tone. Can't wait......

if you have a polytone around you, you could have a pretty good idea of the results by plugging the polytone 'preamp out' into the return of the effect loop of your aer.
i'd be really curious to try it ... and one friend has both amps at his place..

[MilesPG]

Regarding IRs, AMT sells a pedal to load and change IRs, similar to the Logidy, I guess is using the same chip Jorge mentioned, here's the link
https://m.thomann.de/intl/amt_pangae...3AES.EUR%3AEUR

[add4]

or, as Jorge said: this chip http://amtelectronics.com/new/new-20...-cp-16-module/
i didn't find it earlier on my phone but it seems to be very interestign for small pedal builders. i'll try to put my hands on one of those when i fund where to source them... if the price is decent

but then that would definately be in another version of the preamp.. maybe one more complete with reverb and IRs?

[jorgemg1984]

Basically, there are two potential customers: 1) people who gig and want xlr, reverb, low cut, IRs, phantom power, batteries, etc... 2) pepple who don't gig and just want a simple bass treble volume pedal, 1 jack in 1 jack out.

I think we'll need two different pedals

Two other useful possibilites for those who record: two mono outs to split the chain and a buffered fry outyo keep a dry track on the studio, just in case.

[jorgemg1984]

For IRs I've been using an Amplifire or an EPSI plus DI combo, but the AMT will work great too!

[add4]

Basically, there are two potential customers: 1) people who gig and want xlr, reverb, low cut, IRs, phantom power, batteries, etc... 2) pepple who don't gig and just want a simple bass treble volume pedal, 1 jack in 1 jack out.

I think we'll need two different pedals

Two other useful possibilites for those who record: two mono outs to split the chain and a buffered fry outyo keep a dry track on the studio, just in case.

i'll first be happy if i can make the simple one in an efficient way which allows me to keep a reasonable cost

but i'm also up to the challenge of going one or more steps higher to make a more complicated pedal, useful for people.

[lawson-stone]

What about the simple one, but simply with a regular and XLR output? I also like having a separate gain control as you've stated.