Getting a more 303 sounding box..

Discuss x0x construction and related issues

Moderators: altitude, adafruit_support_bill, adafruit, phono, hamburgers

Please be positive and constructive with your questions and comments.
3phase
 
Posts: 203
Joined: Wed Apr 22, 2009 2:06 pm

Re: Getting a more 303 sounding box..

Post by 3phase »

i know it because i tried it..but its not a "real big difference.. One of many little aspects that seem to make the 303 sound like a 303.. the impact of the caps is definitely bigger.

User avatar
rv0
 
Posts: 395
Joined: Tue Jul 14, 2009 4:50 pm

Re: Getting a more 303 sounding box..

Post by rv0 »

Too bad there's no before/after recordings to compare.

3phase
 
Posts: 203
Joined: Wed Apr 22, 2009 2:06 pm

Re: Getting a more 303 sounding box..

Post by 3phase »

its years ago i did that. And it was not the measure i am still looking for on the quest to get the xox to get the sweet and smooth v elvet like quality of a 303 when you bring the resonance up.
And after 24 hours checking it all over again my xox box sounds totally different again but still dont gets that quality.. however..i ve trimmed it for heavy bass and high resonance to make it worthwhile using it at all together with my other machines. But..
:-/.. Its somehow sounddesign at the wrong point.

However..where does the sound differences come from?

One interesting point is the very low resonance you get when the xox is build after specs without any mods..

In the original 303 there is nothing that would indicate that roland has used matched transistors in the filter ladder. Usually you find selected parts in Roland machines marked with a little color dot.
And old components had a wider stray variation than new batches..

but.. would´nt proper matched pairs dont increase the filters ability to resonate?

Has anybody went sofar to really properly match the transistor pairs for the ladder?

3phase
 
Posts: 203
Joined: Wed Apr 22, 2009 2:06 pm

Re: Getting a more 303 sounding box..

Post by 3phase »

But one more detail i found yesterday.. C28 has a remarkable big impact on the sound .. The type of cap really does make a difference here..and i wonder wether the low voltage versions used in the original 303 play a part here since a 16V cap on a 12 volt supply is maybe behaving different than a 35 volt version. In any case astonishing how big the impact on the sound is from this power supply cap alone and highlights once more how sensible the circuit reacts to part choices

However.. i went for something that is 180 degree the opposite of what roland used, a highend elna silmic .. because i liked the heavier bass it creates..the one i most liked was a nichicon KZ ..but that was to big .sweeter sounding but not bass strong as the smaller elna.

I think for now i close pandoras box again to visit the problem at another time again..
Except someone strongly suggest a real matching for the ladder pairs..

User avatar
rv0
 
Posts: 395
Joined: Tue Jul 14, 2009 4:50 pm

Re: Getting a more 303 sounding box..

Post by rv0 »

3phase wrote:C28 has a remarkable big impact on the sound .. The type of cap really does make a difference here..and i wonder wether the low voltage versions used in the original 303 play a part here since a 16V cap on a 12 volt supply is maybe behaving different than a 35 volt version. In any case astonishing how big the impact on the sound is from this power supply cap alone and highlights once more how sensible the circuit reacts to part choices.
interesting.. got a recording of it? :D

rarara
 
Posts: 169
Joined: Wed Apr 05, 2006 9:47 am

Re: Getting a more 303 sounding box..

Post by rarara »

the x0xb0x BOM for C28 describes it as 47uF 10V, what are the specs of the original 303 version?

User avatar
aminoacid
 
Posts: 352
Joined: Tue Jun 20, 2006 5:27 am

Re: Getting a more 303 sounding box..

Post by aminoacid »

C28 is 47/16V in the 303 schematic.

When theese caps are changed they will need to burn in for a while, up to two Days in some cases before they settle in their sound if they will have such an effect.

I just got some carbon film resistors today and and changed about 20 that i thought would be crucial ones.
And i have a little bit more slurry sound now. Either this was the switch to carbon (not sure what was there before, its a adafruit, 4th run.) Or the different values of resistance made it.

Its so funky now.

3phase
 
Posts: 203
Joined: Wed Apr 22, 2009 2:06 pm

Re: Getting a more 303 sounding box..

Post by 3phase »

when it was cole before its just the different values. ;-)

However.. carbon resistors have a higher noise floor.. and this has an effect .. The are also known for a "more natural or musical" tone in the hifi and guitar amp/fx world. When you build a phaser with metalfilm resistors for example the phasing will be so clean that you cant hear it very much..same circuit with carbon resistors and the phaser starts to sing since the noise gives the allpass filters some food.. Change the op amps to old high distortion ones like 741..and you get the so called jet sounds whhoosshh… A total noise free phaser would only do that when you feed it noise.. but on your normal instruments it would sound rather thin.

I am sorry that i dont illustrate every move with test recordings..but i am no scientists and this all eats more than enough time already.
But this thread is not about proving technical theories..its about sharing tricks one has found that make the xox a little closer to the 303.
or? And sofar i dont see contradictions here..just an always growing list of details that probably only in their sum make the 303 sounding like a 303 and no single tweak can achieve that. Always more difficult, or even impossible, to 100% recreate a sound than making a new one..
Last edited by 3phase on Mon Feb 24, 2014 5:16 pm, edited 2 times in total.

rarara
 
Posts: 169
Joined: Wed Apr 05, 2006 9:47 am

Re: Getting a more 303 sounding box..

Post by rarara »

i am getting confused now with regards to C28 - it was said "since a 16V cap on a 12 volt supply is maybe behaving different than a 35 volt version" so what voltage is recommended?

3phase
 
Posts: 203
Joined: Wed Apr 22, 2009 2:06 pm

Re: Getting a more 303 sounding box..

Post by 3phase »

i dont know.. everything above 12 volts should be fine. i didnt had the chance to test 2 caps of the same brand with different voltage capabilitys.. only can state that the cap has an audible fx. Does the voltage capability has an audible fx? Higer voltage ratings usually come with a lower ESR.. the caps i tested was actually low esr types, so the opposite of what a low voltage standard in the original 303 does. But i am actually surprised that this position makes a difference at all..What again put an highlight on the power supply question..since C28 is the gate keeper of the power supply input of the filter .. Thats where the filter gets its juice from.. And even litte changes in that position have an audible impact?

interesting detail

Anyway, it definitely gets a xox closer to 303 choosing similar caps.. But what are similar caps? The manufacturing process has changed and todays standard elecrtolytics have better technical data but often inferior quality than old standard, like the ones used by roland. I almost never had a broken cap in old roland machines.. The quality of these standard sanyos is very good. but the sound is very mushy.. so no cap one would want to use in a highend device but definitely part of that Roland sound..

I once had a real 303 recapped with panasonics bc.. but changed that back to standard types since the sound got harder and not better.. So panasonic BC´s are not a really good idea for a xox too. The mushiness of standard caps actually make the sound more mushy ;-)
However.. a 303 with panasonics BC still sounds more like a 303 than a xox with standard caps.. So the real difference is either somewehre else.. Or its really the sum of a lot of little details..

Just..sofar i havent found a singel detail that was pushing the sound in the direction of that hard to describe feature of the real 303.that singing smooth quality it gets on real hard setting that usually would eat your ear of but you can play it directly into a big pa and it dont hurts..

I wonder if i can find such a dc/dc conevrter like in the 303 somewhere else? old japanese batterie radios? I really dont want to turn my real 303 into a permanent building side and open it all the time.it had its fair share of mods already..without ever loosing that 303 quality. even changed the transistors in the enveloping from 1536 to 945 since i like that more..or have a higher value of C13 as tantal..aso.. The case is abused by extra cv outs.. aso.. it has done enough..i checked for the diodes..but i dont open it to look whether C28 is really just a 10 volt type.
Last edited by 3phase on Mon Feb 24, 2014 5:21 pm, edited 1 time in total.

User avatar
antto
 
Posts: 1636
Joined: Thu Apr 15, 2010 3:21 pm

Re: Getting a more 303 sounding box..

Post by antto »

let me get this straight

your TB-303 is modified?

3phase
 
Posts: 203
Joined: Wed Apr 22, 2009 2:06 pm

Re: Getting a more 303 sounding box..

Post by 3phase »

sure it is..all my synths have little mods.. except the DX7, where is the problem with that? Do you want to say that i dont know how a 303 sounds after 24 years of using one? unmodified and heavy modified ones like the devilfish?
A 303 sounds like a 303 regardless of some mods..even a badly tuned 303 still sounds like one..
A xox box comes in a lot of different sounding shapes.. from ice cold shrill, stiff, to plasto elasto. Just i havent come along one that really sounds like a 303 yet.Something is missing and not as fluent. What dont says that i havent heard good sounding ones..but reminded me more to a 101 than to a 303 than. Not the same thing really. What is a bit surprising seeing how close the xox circuit is related to the original machine.

I get a bit the idea when i read your slightly priggish sounding "let me get this straight" that you have a different opinion here? And what might that opinion be? do you have a 100% 303 sounding xox now?

User avatar
antto
 
Posts: 1636
Joined: Thu Apr 15, 2010 3:21 pm

Re: Getting a more 303 sounding box..

Post by antto »

okay
this answers many questions.

3phase
 
Posts: 203
Joined: Wed Apr 22, 2009 2:06 pm

Re: Getting a more 303 sounding box..

Post by 3phase »

antto wrote:okay
this answers many questions.
you had questions? What about my question? Have you or anybody succeeded in really getting the missing bit of the 303 sound into a xox?
Since you supplied many useful hints one could think that you maybe have nailed it just by adjustments. But is that really the case? what do you think? How close is your xox sounding like a 303 after all the fine adjustments and experiments you did?

3phase
 
Posts: 203
Joined: Wed Apr 22, 2009 2:06 pm

Re: Getting a more 303 sounding box..

Post by 3phase »

antto wrote:let me get this straight

your TB-303 is modified?

Still no answer from you?

So let me get this straight.. you dont know how a real 303 sounds?

ok..that explains a lot..but still some usefull insights you gained into the xox circuit..

Locked
Please be positive and constructive with your questions and comments.

Return to “Making x0x”