Reply to Thread Bookmark Thread
Page 1 of 6 123 ... LastLast
Posts 1 to 50 of 289
  1. #1

    User Info Menu

    Well this kinda got unnoticed on the original thread and I guess it deserves it's own thread.

    An old forum member, quite knowledgeable of electronics, gave me his "instructions" to a an old 80s polytone preamp in a pedal format. Mine is being built by a friend so I can't give feedback on sound but my hopes are high. Mine will be called "Polyclone".

    Hope these files are helpful for others.

    Polyclone.rar - Google Drive

    PS - Sharing was allowed by the mentioned member but please do not use it for commercial purposes.

  2.  

    The Jazz Guitar Chord Dictionary
     
  3. #2

    User Info Menu

    Many thanks for the great info. Nice pcb.

    I can't see a Mid pot, I'd prefer a Mid pot for more control over the middle freq 400 - 600Hz(ish), like the Mega brute's Baxandall tone stack.

    Polytone in a Pedal-polytone-mega-brute-419715-jpg

  4. #3
    This is based on the old Polys, just bass and treble. My Zoom MS100BT has a parametric eq to cover the mids

    Chris (Franz1997) has some info on how to add a mid pot to the old circuits, he'll chime in for sure.

  5. #4

    User Info Menu

    Thanks Jorge, I was just passing...I can't open the files that you posted for some reason.

    I have added a mid control. But be aware that Poly tonestack circuits from different eras have different values; I think the one Guy showed in the other thread was a 90s stack. From memory, this centres the mid frequencies around the 1.2K mark. I find that using appropriately scaled values of around 25n for the mid control caps moves it to a less nasal 400 Hz.

    I prefer the cap values in the 80s era models - maybe your files show that schem. anyway

    It's not hard - but difficult to do without hacking the amp, without a double-gang pot of the correct values.

  6. #5

    User Info Menu

    Quote Originally Posted by Franz 1997
    Thanks Jorge, I was just passing...I can't open the files that you posted for some reason.

    I have added a mid control. But be aware that Poly tonestack circuits from different eras have different values; I think the one Guy showed in the other thread was a 90s stack. From memory, this centres the mid frequencies around the 1.2K mark. I find that using appropriately scaled values of around 25n for the mid control caps moves it to a less nasal 400 Hz.

    I prefer the cap values in the 80s era models - maybe your files show that schem. anyway

    It's not hard - but difficult to do without hacking the amp, without a double-gang pot of the correct values.
    I'll breadboard the circuit and test different caps in the 3 pot Baxandall tone stack and listen.

    Thanks for the info.
    Guy

  7. #6

    User Info Menu

    Do you know of any vendor who is willing to fabricate low volume of PCB for consumer?

  8. #7
    A friend of mine gets his from China but no idea which specific site.

  9. #8

    User Info Menu

    Quote Originally Posted by r_cc_c
    Do you know of any vendor who is willing to fabricate low volume of PCB for consumer?

    I've not tried them, but:
    https://oshpark.com/

    or ask at

    freestompboxes.org ? Index page
    Last edited by GuyBoden; 06-06-2015 at 11:08 AM. Reason: Too fast typing..

  10. #9

    User Info Menu

    Wow - this is all Greek to me but I have wished for something like a portable polytone preamp for years. Is the schematic posted something I could just send to a builder or would they need other info? (Very preferably with a mid knob added like Franz was talking about) All I know is how to solder in pickups and other easy stuff, otherwise I would be all about trying to do this myself.

  11. #10

    User Info Menu

    I'm not an expert, but I've built many electronic circuits and I think that you can use this "TONE TWEQ" baxandall type board to build a similar pedal and tweak the tone stack caps/resist to get the sound you prefer. Even change the Dual opamp TL072 to a OPA2134 if you want cleaner HiFi sound.

    Guy
    Last edited by Dirk; 04-21-2020 at 01:24 PM.

  12. #11
    So, it has arrived. First impressions are pretty good and, as my experience has proved, the best impulse response speaker match is an EVM12L in a closed back cab. Will report again and do a few clips soon!

    One first note is, despite being a baxandall eq, it sounds vastly different from other baxandalls (rc booster, rocket eq, shape eq, ampeg amps, even mambo). There's something completely unique about the Polys.

    Also I added a low cut (high pass) filter to the pedal (30hz-300hz), that works passive, this is it works even with the pedal off so I can also use it with my fender pedal. This feature is an excellent one to cut archtop's rumble and should be included in all "jazz amps" (works much better than turning the bass down which brings a lack of depth to the sound and does not kill all the rumble in my experience).
    Last edited by jorgemg1984; 10-16-2015 at 07:08 AM.

  13. #12

    User Info Menu

    This has got me thinking, if this is just the Polytone preamp circuit could someone use this and pair it with say the poweramp section of a 5e3 tweed deluxe and make a really awesome little jazz amp that meets the best of both worlds? I know enough about electronics to get me in trouble, but maybe someone here could figure it out.

  14. #13
    It seems perfectly possible... maybe even convert it to tubes?

  15. #14

    User Info Menu

    Now we're talking! I love the warmth of tubes but the polytones sound so good.

  16. #15
    I don't have the skills to do it but it seems perfectly doable - a polytone preamp converted to tubes and a 5e3 tube power amp.

    Open back cab with an Altec 417-H?

  17. #16

    User Info Menu

    This is doable. I have Polytones from the 70s, 80s, and 90s. I haven't yet dabbled in one with the Sonic circuit. I have or have had, thus, Polytones with the plain Tolex and CTS speakers, the fuzzy cabinets and CTS, the diamond black Tolex with early Eminence speakers, and the blue Tolex with Eminence speakers. The tone stacks evolved from just bass/treble and the brite/normal/dark slide switch, to the bass/mid/treble with slide switch. Some of the early amps also had "room eq" switches that were actually negative feedback loop on/off switches.

    In my estimation, the best sounding Polytones are the ones with the simplest tone stack, i.e., just treble/bass and the slide switch. I would copy this in a pedal that I would make.

    As far as coupling this with an amp/cabinet goes, just about any good amplifier would work. It should not be underestimated, however, how much of the Polytone sound is tied up in really driving an amplifier hard into a low-impedance, heavy-duty speaker in a closed back cabinet. This will sound different than, say, running a Polyclone preamp into a power amp working into a Fender Twin Reverb 15-style open-back cab. That will sound good, but it will be different than a close-back Polytone cabinet with a low-impedance 15" driver.

  18. #17

    User Info Menu

    Tube powered Polytone sound gets another vote from here!

    I love my Mini Brute but when I compare it to my Princeton Reverb the "naturalness" and the headroom of the tube amp just makes me breathless and thinking that MB sounds a bit dull. As any SS amp.

    But first I am waiting keenly further reports about the pedal from Jorge!

  19. #18

    User Info Menu

    Yeah if the pedal ever becomes available for purchase I'd be all over that.

  20. #19
    If anyone wants this pedal to be built my tech can build one equal to mine.

    miguel.oliveir@gmail.com

    He's based in Portugal but he ships overseas. My pedal has a few custom options (OPA2134, pump charger to 18v, low cut, stereo out) and killer looks but he'll customise to your needs.

    I'll post clips and photos in maybe a week.

  21. #20

    User Info Menu

    What is the pump charger to 18v and is the OPA2134 just an IC chip that you prefer?

  22. #21
    The pump charger doubles internal voltage, so you feed 9v and the pedal has 18v internally. Good for headroom.

    The OPA2134 are my absolute favourite op amp for cleans - I modded all my SS amps and eq pedals to have them.

  23. #22

    User Info Menu

    Jorge
    the low cut feature will work wonders when the pedal is off for users of the 5e3 Deluxe amp. That circuit has such wide band pass filters that it is flat to ten hz. And, it has no bass roll off control. This will tame the low bass on the Deluxe that can make a muddy tone.

  24. #23
    destinytot Guest
    Fascinating - I'm keen to find out more. The electronics are beyond me, but I do get an amazing tone when I feed a line from an Evans RE200 into a Polytone.

  25. #24
    Quote Originally Posted by Greentone
    Jorge
    the low cut feature will work wonders when the pedal is off for users of the 5e3 Deluxe amp. That circuit has such wide band pass filters that it is flat to ten hz. And, it has no bass roll off control. This will tame the low bass on the Deluxe that can make a muddy tone.
    The low cut has been a life saver. I find that archtops plus humbuckers plus either fender or "jazz amp" tone stacks tends to produce too much low end (I don't have any problem with my flattop or my classical). For years I struggled with that - most of the bass knobs can't even kill all the rumble and even if they do I don't like running bass knobs too low, it makes the highs too shrill (in either fender or "jazz amp" eqs).

    So one day I was in some music producers forum and someone was saying that he always high-passes everything below 150hz in guitar tracks - and after a while I got a Pocket Pod HD from Line6 which had a low cut incorporated and it worked wonderfully. I wish I had found this a long time ago!! My tech build me one I still have and use at a very small board I have in my car for when I use "rental amps" and it has worked great with all amps I tried so far. When I decided on the Polyclone pedal I had to have it incorporated and still passive so it would work with any other preamps I buy. So far it's great with the Polyclone and the Barb EQ and I suspect it will be with other pedals too!

    Funny thing is, it's the cheapest easiest pedal to build (basically the opposite of a guitar tone control).

  26. #25

    User Info Menu

    Quote Originally Posted by Greentone
    Jorge
    the low cut feature will work wonders when the pedal is off for users of the 5e3 Deluxe amp. That circuit has such wide band pass filters that it is flat to ten hz. And, it has no bass roll off control. This will tame the low bass on the Deluxe that can make a muddy tone.
    Bruce at Mission Amps has a humbucker mod that allows the use of the normal channel's volume control as a low cut when plugged into the bright channel. It's switched so that you can run the stock circuit or the modded circuit. It's not perfect for this use but works pretty well at taming the boisterous bass of the 5e3 circuit (I run my 5e3 head into a RE 12 so it probably acccentuates the bass even more than an open backed combo cab.). I wonder about pulling the bright cap out of the circuit to result in two normal channels...
    Last edited by Cunamara; 10-17-2015 at 01:07 PM.

  27. #26

    User Info Menu

    Two nights ago, a fellow musician brought a mint condition 70ies or 80ies Minibrute IV to a jamsession. Or at least I think it was that model: only bass and treble controls, no mid pot, 15" speaker, great reverb.

    I have very limited experience with Polytones but man, this one in combination with my ES-125 was tonal heaven! All the other guitarist in the room agreed and two of them begged me to use my guitar on the Polytone because the sound was soooo good! It was just THE classic old school jazz sound that I have embedded in my brain!

    So I am very interested in this pedal!

  28. #27

    User Info Menu

    Interesting pedal!

  29. #28
    So for anyone interested in the low cut... I did some more tests and this should be an active design, using an opamp like an OPA2134 to serve as buffer and "make up gain". As it is, passive, it looses too much gain. I use so many pedals this artefact was not evident...

  30. #29

    User Info Menu

    So how would a person not skilled at building things like this obtain one of these pedals?

  31. #30
    Quote Originally Posted by jorgemg1984
    If anyone wants this pedal to be built my tech can build one equal to mine.

    miguel.oliveir@gmail.com

    He's based in Portugal but he ships overseas. My pedal has a few custom options (OPA2134, pump charger to 18v, low cut, stereo out) and killer looks but he'll customise to your needs.

    I'll post clips and photos in maybe a week.
    Here

    I strongly recommend an on / off switch for the low cut AND making it active. Or not adding it if you don't feel the need!

  32. #31

    User Info Menu

    Quote Originally Posted by lawson-stone
    So how would a person not skilled at building things like this obtain one of these pedals?
    There is thousands of DIY builders making clone pedals and designing their own pedals in DIY Stompboxes, The Gear Page etc forums. Try to find there someone who could build this to You. I'll bet You'll find there one who lives in Your neighborhood!

  33. #32

    User Info Menu

    Haha!

    I actually had the same idea after recording my polytone from the line out (output of preamp) and loving its sound. I really wanted to check if a polytone-in-a-pedal could bring the 'polytoneness' to a regular fender amp found in a jam session for example. I love what the polytone preamp does to my sound it's just something special.

    I started a few months ago and stopped halfway through creating the PCB due to time constraints and priorities shift.
    My version is based on my 82' Mini brute 1 and includes the mid pot. I also included the charge pump (great minds think alike).
    i really have to finish the design of this PCB and start building it, but i have so many useful pedals projects in parallel already (special buffer, analog delay, mixer pedal, django electric sound type overdrive, bypass loop with mix (mix any distortion with clean signal), other wierd stuff or tests .. ) that i can't keep up.

    Pedal building is fun and addivtice but also SO time consuming and it's sometimes hard to finish complete projects (at the moment with no place to drill and varnish at home) and a new house to paint and to work for..

    Anyway, i'm glad that someone tried this and that it worked.. i'll start this project again and probably put it in priority
    Last edited by add4; 04-29-2016 at 09:25 AM.

  34. #33

    User Info Menu

    add4, do you have a schematic of your version with the mid pot? Care to share it? I've been looking for a schematic of a Polytone (Baxandall) preamp with a mid-pot but haven't found one I found useful. Thanx!

  35. #34

    User Info Menu

    mine comes from the schematic that i found on the net, that i verified as similar to my mini brute 1
    (it's actually the complete schematic with reverb and distortion, but crossing this schematic with the ones posted earlier in this thread i created my version (unverified yet) , similar to the one in my amp . i basically removed the distortion and reverb driver, and used the last stage from the other schematic)


    Polytone in a Pedal-polytone-mega-brute-schematic-jpg

  36. #35
    Quote Originally Posted by Little Jay
    add4, do you have a schematic of your version with the mid pot? Care to share it? I've been looking for a schematic of a Polytone (Baxandall) preamp with a mid-pot but haven't found one I found useful. Thanx!
    Jay do you know Chris (Franz1997)? He's a really nice guy and he has added a 400hz mid pot to his old Poly I believe. PM him!

  37. #36
    Quote Originally Posted by add4
    Haha!

    I actually had the same idea after recording my polytone from the line out (output of preamp) and loving its sound. I really wanted to check if a polytone-in-a-pedal could bring the 'polytoneness' to a regular fender amp found in a jam session for example. I love what the polytone preamp does to my sound it's just something special.

    I started a few months ago and stopped halfway through creating the PCB due to time constraints and priorities shift.
    My version is based on my 82' Mini brute 1 and includes the mid pot. I also included the charge pump (great minds think alike).
    i really have to finish the design of this PCB and start building it, but i have so many useful pedals projects in parallel already (special buffer, analog delay, mixer pedal, django electric sound type overdrive, bypass loop with mix (mix any distortion with clean signal), other wierd stuff or tests .. ) that i can't keep up.

    Pedal building is fun and addivtice but also SO time consuming and it's sometimes hard to finish complete projects (at the moment with no place to drill and varnish at home) and a new house to paint and to work for..

    Anyway, i'm glad that someone tried this and that it worked.. i'll start this project again and probably put it in priority
    Hi Arnaud, I would love to hear your thoughts on the pedal when you build it. Good to see you're still building stuff, luckily I am unable to solder

  38. #37

    User Info Menu



    you should start it's the easiest part actually!!!
    think of all the crazy stuff you could try..

    Seriously thanks for your kind message. i'm building stuff on and off. I still try to prioritize playing, and even that has been slowed down a little lately.
    I've had this huge breakthrough in my guitar playing and now that i manage a lot of situations really better, i have less drive for working all that stuff out as i used to do. I geuss it's just a momentary thing. I also started playing more and practicing less, and writing some music too .
    and also started doing sports again . my free time always was divided between music and sports and apparently after a few years focused on music, i much enjoy doing sports again
    Last edited by add4; 01-17-2017 at 07:03 AM.

  39. #38

    User Info Menu

    If anyone ever gets this to the point of being willing to make one on commission for a reasonable price, I'd love to buy one. I don't want to just drop onto an unknown website and ask. But if any of you guys ever build one of these (I like the mid range knob too) and can quote a price, I'd love to be your test market!

  40. #39
    Quote Originally Posted by add4


    you should start it's the easiest part actually!!!
    think of all the crazy stuff you could try..

    Seriously thanks for your kind message. i'm building stuff on and off. I still try to prioritize playing, and even that has been slowed down a little lately.
    I've had this huge breakthrough in my guitar playing and now that i manage a lot of situations really better, i have less drive for working all that stuff out as i used to do. I geuss it's just a momentary thing. I also started playing more and practicing less, and writing some music too .
    and also started doing sports again . my free time always was divided between music and sports and apparently after a few years focused on music, i much enjoy doing sports again (- 10 kgs in 2 months )
    I know it's easy but I need to focus on music... I have to stay from pedals and studio stuff, I like them too much

    Yeah, too much stuff we like to do... no time for everything!! Keep me posted on your Polyclone pedal progress!

  41. #40
    Quote Originally Posted by lawson-stone
    If anyone ever gets this to the point of being willing to make one on commission for a reasonable price, I'd love to buy one. I don't want to just drop onto an unknown website and ask. But if any of you guys ever build one of these (I like the mid range knob too) and can quote a price, I'd love to be your test market!
    Lawson as I said I can't solder, I just have ideas (too many ideas)! If I did I would gladly build you one and send it to you - some guys here can and will help you for sure!

  42. #41

    User Info Menu

    Quote Originally Posted by lawson-stone
    If anyone ever gets this to the point of being willing to make one on commission for a reasonable price, I'd love to buy one. I don't want to just drop onto an unknown website and ask. But if any of you guys ever build one of these (I like the mid range knob too) and can quote a price, I'd love to be your test market!
    Haha!

    for me there will never be a market! building a pedal takes about 8 hours for me (building the circuit 2h, offboard wiring 2h, drill box according to the board specificities 1h, apply artwork on pedal 2h, find the usual small problem in a build and solve it 1h) and it's not counting the time spent on designing the pcb, producing it, creating the artwork and the drill template, ...
    so i'm selling some to friends in the belgian jazz scene who really want some stuff they heard (i modded a rat used on the LG jazz collective album, and have 3-4 guys using a few pedals from me, one even had half of his boad built by me ... but i'm practically giving them to him since hess my best friend and i want to see him succeed in music ) for it, and most are for me (my pedalboards are too small ).

    What i mean is that if i wanted to make you pay for it it would probably be closer to a boutique price than a chinese factory price if i wanted to have a little something for my hours. This is probably where you'll say you prefer something else
    Even worse: i have a few orders (for friends as i said) in the backlog and i might take months before i can actually give you something..

    That's why i'd avise you to contact Jorge's friend who apparently found a way to build pedals on demand and rather cheap

    If you absolutely don't find an other solution i can maybe do it but within the limitations i gave you .. don't hesitate to contact me if the rest doesn't work (i mean .. i HAVE to order the pcbs by multiples of 3 so i might have 2 sleeping in a cardbox)

    hope that helps
    Last edited by add4; 04-29-2016 at 11:01 AM.

  43. #42

    User Info Menu

    Quote Originally Posted by jorgemg1984
    Lawson as I said I can't solder, I just have ideas (too many ideas)! If I did I would gladly build you one and send it to you - some guys here can and will help you for sure!
    Jorge's ideas are usually veru good in terms of pedals and sounds!

  44. #43

    User Info Menu

    Hey guys,

    I stared working on this again and here is the schematic i plan on using in case it can help someone

    Polytone in a Pedal-polyclone-jpg

    this is basically the polytone mini brute preamp with the mid pot, and the charge pump (i actually choosed to use the charge pump to provide -9volts and +9volts, it's closer to the original polytones than using +18v). the results should be the same from the audible point of view.

    i'm still thinking on adding or not the low pass filter discussed here, and where/how to add it if i do.


    i'll try to finish the circuit for today

  45. #44

    User Info Menu

    Hi add4,
    Did you ever continue working on the preamp? I'm curious about cuz I'm having like a lot of gigs in a place far from my place and they have a backline but no amps.
    C
    Last edited by Cris Gomez; 01-11-2017 at 03:30 PM.

  46. #45

    User Info Menu

    Hi Cris,

    Sadly, no.
    The good news is that i recently had a few pedals ordered and i then discovered someone who can help me with the enclosure preparation so i now can build pedals a good bit faster, and with a far better enclosure quality. So i'm currently working towards making small batches of pedals and sell them. The polytone preamp could be one of those if i can find a few people interested that could be worth investing some time in. I'll put it back on my (already gigantic) list of things to try and test.
    Last edited by add4; 01-11-2017 at 04:17 PM.

  47. #46

    User Info Menu

    Quote Originally Posted by add4
    i'm still thinking on adding or not the low pass filter discussed here, and where/how to add it if i do.
    Eager to hear results! And as a many year Polytone user I would not worry about low pass filters. Or Joe Pass filter!

  48. #47

    User Info Menu

    I'll try to do that after the booster project I'm working on right now.

    Some images (because im proud of these Polytone in a Pedal)



    Envoyé de mon iPhone en utilisant Tapatalk

  49. #48

    User Info Menu

    Quote Originally Posted by add4
    I'll try to do that after the booster project I'm working on right now.
    Some images (because im proud of these) Polytone in a Pedal)
    Wow! And for a reason! If these sound as good as look they sound fabulous!

    Clones or original designs?

  50. #49

    User Info Menu

    This booster is based on a RC booster with two main changes: earlier break-up so that passed noon the drive starts to break-up slightly but it's more like a light growl or added harmonics than overdrive. And I changed the frequencies of the treble and bass knobs to my personal taste.

    There is a limited number of possibilities to amplify a signal anyway so my idea here is to use the architecture of a pedal with the sound quality I am looking for top get a specific effect. Here, I think that combination being a decent guitar player
    With an ear for sounds and an understanding of how to make these signs happen is the added value. For instance i made myself a rat based pedal with a few mods to get it more useful for jazz (including a pot to stimulate the volume control of the guitar at the input. To me the rat really shines with the guitar volume on 5-7 but I like to play with my volume 10 on clean so I can now just turn the pedal on and have both the volume down and the effect on. Simple but useful addition Polytone in a Pedal


    Using the same idea you can use the tubescreamer circuit to get wildly different sounding pedals. Or the big muff circuit can go from scooped fuzz to mid boosting overdrive.

    Here, Interestingly, the RC booster circuit is not so far from the Polytone preamp: bandaxall tone stack, op amp amplify stage,...

    I also have some 100% original designs in the work, but not for this booster


    Envoyé de mon iPhone en utilisant Tapatalk
    Last edited by add4; 01-12-2017 at 07:13 AM.

  51. #50
    Just to clarify - the filter on the Polyclone is a low-cut (high-pass) filter that now has been upgraded to active and has an on / off switch, so it can be removed from the circuit. When off it has no effect on sound and it can be quite useful when playing with boomy archtops / cabs / rooms - lowering the bass knob will make your sound thin, the low-cut will not.