Modding a Roland Rhythm 33 (TR-33)

DenDer · December 15, 2008, 09:16:15 AM

Just downloaded the 3 zip packs but this sounds good Graham.....nice deep BD, and i like the conga sounds. Could you maybe upload a bigger mp3 to vintagesynth? Like a pattern or something.

gmeredith · December 15, 2008, 09:54:18 PM

No problems! I'll try and get one happening this week.

Cheers, Graham

DenDer · December 15, 2008, 10:23:59 PM

looking forward to it......the BD of the TR33 is way deeper than that of the Dr55......they are both boomers but the Dr55 has more punch in it while the TR33 is more a constant door shaker. I really want one now!!! Nice to stack with the Dr and a 606...jumjum...

gmeredith · December 16, 2008, 05:45:49 AM

Yeah, i'm pretty impressed by that kick. It really is BIG when I run it through my PA speakers. An interesting thing too is that there is an adjustment pot in the main mix out that I originally thought was a tone control, but is actually a noise balance control for the noise oscillators (for the noise part of the snare, hihats and cymbals) - when you turn it all the way down, the hihats disappear and the snare becomes this amazing sharp impulse click noise, like something Kraftwerk used in their song "Numbers".

Here is a small demo with the modded kick, with lots of decay. The snare is also tweaked so as to be not so ringy and is more hissy. Also, using the individual outs has made it possible to clean up the sounds. Compare this to the "TR33 original preset" in the next post below.

Cheers, Graham

gmeredith · December 16, 2008, 05:48:01 AM

The original sounds:

rqckmounted · August 07, 2012, 06:23:50 PM

Hi

I have just got myself a tr-33 and would like to mod it like some of then users did on previous post.

I would need a bit of guidance perhaps mod schematic or such to help me out!!!

anyone out there have some aditionnal technical info.?

thanks

gmeredith · August 24, 2012, 05:08:21 AM

Sorry for missing this post for such a long time!

Here's the TR33 service manual on my band's website:

http://www.warningwillrobinson.com.au/index_files/InstrumentManuals.htm

Cheers, graham

Circuitbenders · August 24, 2012, 10:25:11 AM

its almost as if you're taunting me!

I've just spend about 2 days searching everywhere for a service manual or schematic for a TR55, and all i can find is the TR33 and TR77. Its like the TR55 doesn't exist.

You wouldn't have to know a source of those ancient inductors that are used in these machines would you? I'm guessing they were custom wound for Roland, but the rimshot in this TR55 seems to have a dead one and i'm having difficulty finding anything close to a drop in replacement.

gmeredith · August 30, 2012, 06:14:15 AM

Again, sorry about being so slow in replying - uni semester has been busy. I've also switched on the notifications funtion on this board so i get emailed when you reply

No, i don't know where you could get an exact inductor from but I do know that you could swap it for another sound's inductor of the same kind and rating to at least test that that is what is wrong. Have you troubleshooted it to the inductor? Swapping one would confirm this - and at least if there is some sound that is not used much like a maraca or something then you've got your snare back and happening and fix the maraca at a later date. You could also have a go at hand-winding the dead one - you have nothing to lose if you know it is actually dead.

Cheers, Graham

gmeredith · August 30, 2012, 06:22:59 AM

This guy here claims to have the TR55 service manual on his lists, you could give him a try:

http://synthsfl.tripod.com/smanuals.html

cheers, graham

Circuitbenders · August 30, 2012, 11:57:20 AM

I swapped the inductor from one of the bongos with the rimshot and it worked, albeit at the wrong pitch, so it must be the inductor thats gone. Having said that, it doesn't test as being dead in any sense other than that it just doesn't work so i'm starting to think its not the original part anyway. How can an inductor possibly just stop working, its just a coil of wire?

Every inductor in these machines appears to be custom wound for each sound, and none of them are labelled, so without the schematic theres very little chance of finding out whats meant to be in there. Even if i could find out what its meant to be, i don't think anyone has made inductors of values that big since the 70's.

Why did i throw away those late 70's radios i had a while back without harvesting them for parts first!

Looks like i'll have to actually pay for a service manual!

Gordonjcp · August 30, 2012, 05:20:49 PM

"How can an inductor possibly just stop working, its just a coil of wire?"

It goes open-circuit. Are there really no markings at all on it? You could measure the one you tested it with, and see if you can guess what would be close.

Circuitbenders · August 30, 2012, 10:07:59 PM

Theres four others in there that look absolutely identical but measure anywhere between 30mH and an astonishing 1430mH. Three of them have a resistance of between 30-60 ohm, but the 1430mH one measures 4.3K, which is ridiculous. Thats measuring them out of circuit

They all have a V followed by a number on the top, i.e V52, but i don't think that relates to the inductance value. I'm guessing thats a Roland code.

The rimshot/clave circuit in the TR33 which is very simliar to the TR55 has a 700mH inductor on the schematic.

The dead one in this TR55 appears to measure at around 36mH, with about 30ohms resistance, but it seems to just be acting as a dead short in the circuit. I'm not sure i trust the reading, especially as the 1430mH / 4.3K one seems to sound nearly correct for a Roland rimshot when i stick it in the circuit.

I actually unwound the dead one and rewound it, testing it every foot or so to see if it unwinding it had stopped a short. Theres no breaks and no shorts in it.

I've just ordered a load of various inductors from mouser so hopefully i'll be able to bodge something together that gets close to what the original was meant to be.

gmeredith · August 31, 2012, 12:24:46 AM

Well that is totally confusing then. They must be an in-house roland component, wound specailly to suit them. Hopefully that means that you can wind your own to make it work then - maybe also you can make custom ones that will give your snare a modded sound.

cheers, Graham

Gordonjcp · August 31, 2012, 02:17:38 PM

Measuring the resistance won't be helpful unless you use a true DC ohmmeter - most digital multimeters get horribly upset when you try to measure the resistance of a reactive component ;-)