General Discussions => The Lab => Topic started by: peat on January 10, 2010, 01:52:00 AM

Title: RSP Technologies Tube Saturator
Post by: peat on January 10, 2010, 01:52:00 AM
Can't seem to find anything about this, let alone the company.

Seems to be well built, looks like a 12ax7 and a THAT 2155 in each channel,

Just curious about it, i think this one needs a retube, get alot of crackle when adjusting one of the pots (maybe new pots too)
but the metering is funky, not sure what the trimmers are doing

any help, info, schematics would be awesome!

Title: Re: RSP Technologies Tube Saturator
Post by: Adky on January 10, 2010, 11:18:47 AM
More closer pictures to the PCB and the read out on all the IC please?
Title: Re: RSP Technologies Tube Saturator
Post by: JohnRoberts on January 10, 2010, 11:31:25 AM
Rocktron went out of business years ago (based in Mich IIRC)... I think some of the old crew are still around trying to sell a big dog sound reinforcement system.

Many people have tried to mimic tubes in solid state, or even sell real tubes, for people wanting that "tube" sound.  The market for such gimmicks is pretty fickle and ebbs and flows with fashion like regularity.

I believe Rocktron had one or more patents for their single ended NR work. If there is anything protected in that effects unit, there should be a patent notice on the back and what it is, in the patent files.

Title: Re: RSP Technologies Tube Saturator
Post by: guavatone on January 10, 2010, 11:48:50 AM
Is it the drive pot that crackles?
Title: Re: RSP Technologies Tube Saturator
Post by: peat on January 11, 2010, 02:10:24 AM
just about to take some closer photos, and will list all the IC's

just did some tests on it,

The left drive pot is very crackly, but seems to work fine if you get it in the right spot
I swapped the tubes and it's the same problem, so definitely pot's need replacing.

It seems that when the metering is switched to saturation, its showing the level at the drive pot
and when switched to output, the level at the output pot (pretty obvious)

I ran a -12dBFS sine into it and set drive to give 0dBVU in saturation metering
and set output to get 0dBVU in output, this returned -12dBFS to my 002, so that seems like a good thing

One of the trimmers is definitely some sort of high frequency control, super bright to super dull.
i couldn't hear much when adjusting the other trimmer.

The tubes in it are 'Audio Classic' 12ax7 / ecc83/7825, never heard of them.
I noticed that with drive and output all the way down, sending the -12dBFS tone into gave about -7dBVU on the left channel and -6.5dBVU on the right.
So i thought, i'll try some different tubes,

put a pair of groove tubes ecc83's in. they worked fine, but had a huge difference in channels, ~10dB. swapped tubes and the level difference followed the tube.
Tried another set of GT ecc83's. same thing, huge level difference. Guess I'll have to hand match some tubes if i want to replace them (adjusting the internal trimmers had no effect on this and the level difference was visible on the RSP meters and on my return meters in PT)

Running some music through it, it sounds ok, distorts fairly easily with the drive control, not a great distortion. (this was running cd master level program through it but)

John, there is a little sticker referring to patents, it says:

This product may be covered by one or more of the following:
U.S. Patents # 4,538,297
4,647,876 - 4,696,044 - 4,745309
4,881,047 and 4,893,099 with other patents pending and foreign patents pending.

ok, i'll take some photos!
thanks for your help guys
Title: Re: RSP Technologies Tube Saturator
Post by: Adky on January 11, 2010, 02:44:49 AM
Well, Sounds like you need to replace that pot for sure, or try Lubricate it a bit before you go all the way, i guess that pot is controlling the output of the tube, and a 12AX7 is the loudest in its range, try to swap it to a 12AT7 or anything in the 12A?7 lines, for different tone and sounds, for a perfect balaced dual channel you sure need to have matched tubes, to what I understand and guess the unit maybe is a solid-state thing that have some kind of compressor there and then finally it pump the signal to a tube gain or buffer stage , the drive knob maybe just controlling the audio hitting the tube stage input................waiting for your extra pict and IC path, so that I can do a better guess. and another thing youc an do is to check the Plate Voltage on the Tube, to see rather the tube is getting normal voltage not staved.  :-\
Title: Re: RSP Technologies Tube Saturator
Post by: peat on January 11, 2010, 03:41:22 AM
PSU (it has an external 9VAC 1.5 supply)




tube sockets




complete board




ch 1


drive pot


output pot

Title: Re: RSP Technologies Tube Saturator
Post by: Adky on January 11, 2010, 04:41:51 AM
OK! I think this thing work more or less lke those fancy tubed guitar effect, to my guess, it should work like this , the 5532 is the balancer and un balancer for the input and output , and then the TL064 do some of those make up or gain stage and then the VCA maybe controlling the blend of original sounds and the "tube" sound , by useing a 9VAC I am very very sure it is on a staved plate design, so thue shoudl be makeing all the distortion so called TUBE sounds.  let say if you want to improve the performance , you could re-cap all the audio cap with really nice cap, and bypass it with a 0.1 uf wima and sockeet all the IC , swap out the LF353 with OPA2604 and the TL064 with MC33079 or OPA4132, then the 5532 with a AD826 , also you could replace the diode with fast recovery diode and bypass with 0.1uf wima cap...........and so on, finally it really depends on what you want to do to it, it is just my personal opinion only . try one thing, take the tube out and see rather you still get sounds coming out of the box.......... :o
Title: Re: RSP Technologies Tube Saturator
Post by: peat on January 11, 2010, 09:07:52 AM
thanks for your help adky

i tried it with the tubes out of their sockets, and no signal passes

I guess ill change all of the pots to start with, get some chicken heads on the front and see what it sounds like
could be ok for recording here and there, dont know about mixbuss duties though

im just about to order some stuff, might get a bit more and try some of the replacements you mentioned.
do you mean to replace all the smaller electrolytics with wimas?
Title: Re: RSP Technologies Tube Saturator
Post by: Adky on January 12, 2010, 12:10:15 AM
if you took the tube out then it got no sounds, it means the audio signal "must" pass thur the tube stage, so replacing the tube will affect the "tone" , one really easy things you can check to see if the caps are in the audio path are take a DMM and poke the Negative leg of the Electrolytic and then poke to the Pin 1 (usually ground) of the input or output , if it go bee bee bee, that mean it is not in the signal path, if it doesn't then it is , so you can go ahead and replace that not so good quality or looking cap to something really nice, a same value replacement will be fine, I guess they usually either 22uf, 47uf, or 100uf. after replaceing it you can also connect a small value let say 0.1uf wima or ERO type cap in parallel to let more "high end" pass thur it. what i usually do is I will double the value of the electic cap if space are avaliable. you can do just one channel first a step at a time, and compare with the other channel to see rather you hear a different. take your time and have fun. fyi: replaceing all those IC to those BB or OPA they do use up more power you might concider a bigger power supply after you done if the power supply seems small or making heat. good luck with it. you might also consider tracing out the schematic your self.
Title: Re: RSP Technologies Tube Saturator
Post by: Kingston on January 12, 2010, 05:10:41 AM
also you could replace the diode with fast recovery diode and bypass with 0.1uf wima cap

No wanting to get into discussion on modifying a lofi starved plate stomp box, but the above piece of advice is wrong.

Contrary to the popular (audiophile fueled) belief, diode bypass caps do more harm than good, especially bulk values like 0.1uF that do not relate to real world. Diode bypass caps were much needed band aid for slow diodes back in the day (20 years a go?). Schottky or other fast diode performance is harmed by smoothing with caps, since there is nothing to smooth.
Title: Re: RSP Technologies Tube Saturator
Post by: Adky on January 12, 2010, 06:28:06 AM
Well, absolutely, if you replaced with fast diode then don't add the bypass cap, but you can always try it to see rather you notice a different......... bypassing the diode is the last thing I will do, also I have very good result replace those 1N400x to faster diode such as some ON Semi , or Telefunken ones. and you can always replace all your resistor if you got all that time, there are so many things you can do to a box, but just really depends on what you are after,. and mostly what you don't like and what you want it to be. try for yourself. ;) P.S. one thing at a time, and make notes. Have Fun! good parts does make a different, thats why I would always want to swap out the cheap tube. why the tube? because it is the first thing you can pull of the socket.......... ;D but to be honest, when I am after some tube over driven sounds I usually will use a real tube distortion box (about 4 gain stage type )and parallel the direct sounds and the wet sounds back to the console and then blend it the way I wanted, that way I can get better control and got the dynamic on hand.
Title: Re: RSP Technologies Tube Saturator
Post by: superslaukey on January 16, 2010, 03:30:08 AM
Hi everybody,

I`m new to the forum - please don't mind my bad english, I'm from germany  ;D

Like peat I am trying to find the schematics for the RSP Saturator. I have already contacted someone at Rocktron/GHS who was involved with RSP in the 90ties but he doesnt have the schematics, he only had the manual but it doesn't contain any helpful infos.

So, currently I`m redrawing the schematic for the Saturator, which isn`t an easy task, especially for beginners like me. Any help would be appreciated.

Since some of the posts already "disqualifiy" the saturator because of its starved plate design, here is why i am doin all this:

The first tries with this unit when I got it were really dissapointing. The unit distorted easily with just a twist of the pot and the distortion wasn`t pleasing at all, it was nasty. So I tried swapping the tubes - no improvement (I used vintage NOS Telefunkens!). At first I just wanted to sell the unit straight away and then I discovered that with a lower input from the DAW, you can have a much better control of the distortion (because of the wider range you can go with the pot) and also the distortion itself was more pleasing! I do not know why this is but maybe other components in the circuit contribute to the overall sound too. What I did then was to take out the TRS input jack and wire a passive volume contorl to this input ( That helped to really improve the distortion characterisik and you can somehow even tweak the "tone" of the unit.

The other thing that peat mentioned is the high cut, a trimmer on the pcb. I replaced it with a pot. With this additional control you can go from really vintage (max high frequ. damp) to "modern"/industrial like, according to the settings of the (new) input and drive controls.

Now, this really helped to turn the unit into a really great tool. I made mixes with and with out it and it not only improved the room info content and thickness of the sound (a little hf-damp is all you need). Now my saturator is much more than a saturation tool, it is a COLOURATION TOOL.

So, despite the starved plate design it is a really great tool and i never got some of the sounds/colourations out of any other plugs/hardwares i used so far. I don`t compare it to real tube designs and exiter like tools because it is nothing like this. It is just a cool tool to add fatness/colouration/tone to a mix.

Hopefully we`ll get the schematic worked out   :)