Sound On Sound of RE-301 and 501

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dub vibe
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Sound On Sound of RE-301 and 501

Post by dub vibe » Fri Dec 26, 2008 4:11 am

Hello, I am very much interested in the Sound On Sound on RE-301 and 501 (and SRE-555) and trying to buy one of those.
Could anyone tell me how the SOS on each 301 and 501 works? I looked up on internet, but could get only brief explanations about it.

I know that those have erase head at different position.

my questions are,

- Can you make a long loop which repeats more than twice? with both models?
- Can you use echo and chorus effects during the SOS? (can you make loop with echo sound on it?)
- Maybe in other words, Which head does the SOS mode cancel? (or doesnt cancel any?)
- If it makes loop, how long does the looped-sounds last? (do they fade out?)

I own Line-6 and make loop with it but its too short (14 sec or smth?). I also use a laptop to make loops, but i feel thats not what i want.
I need some analogue physical thing to play with... of course, I need an analogue reverb and echo, so those space echos seem my dream gear.

any comments would be appreciated, especially from actual users!
thank you!

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Post by interruptor » Mon Dec 29, 2008 2:35 am


Detailed info on the operation of the RE-301 and the RE-501 can be found in the user manuals:
click here for RE-301 manual
click here for RE-501 manual

Unfortunately these do not provide enough details on the interior of these machines. Therefore I connected a guitar to the RE-301 and listened closely to figure out the internal wiring by ear. Below is a simplified schematic of the unit based on what I heard (see attached image).

- In normal echo mode the incoming sound (IN) is recorded on the tape by a record head (R) and read off the tape by three different playback heads (1,2,3). The heads are switchable, so either of those or a combination of two heads or all three heads can be activated.

- repeated echos are generated by looping back the signal from the three playback heads to the record head.

- In Sound-on-Sound mode an additional playback head (SoS) is switched on. It is located right at the end of the tape loop before the erase head (E). The erase head is NOT deactivated in SoS mode. This means everything that is on the tape is played back exactly once. Repeated loops or even layering of several parts is not possible.
(You can layer two parts: Play a first part; Then while this first part is being repeated play a second part live. After this your second part is being repeated once and the first part cannot be heard anymore)

- The loop time depends on the length of the tape loop and on the tape motor speed. In my case with a factory loop this ranges from ca. 12 to 38 seconds. You could achieve longer times by splicing your own extra-long tape loops.

- Everything which is on the tape is also played back in SoS mode. If you have echoes activated, then these are being recorded on the tape and therefore can be heard during replay. The other two effects however (chorus and spring reverb) are not recorded on the tape. These will not be heard at playback time. See the wiring displayed in the schematic..

- Contrary to the RE-301 manual which claims that additional effects can be added during playback in Sound-on-Sound mode the SoS head is routed directly to the output. Chorus and reverb settings do not affect the SoS signal!

- The spring reverb is fed by the input signal as well as by the signals from playback heads 1 to 3. (But not by the SoS signal as mentioned above)

- If you switch off all effects and enable Sound-on-Sound you will hear the dry input signal repeated once after 12 to 38 seconds.

- The spring reverb and the chorus can also be used on their own when tape delays and SoS are switched off. Somebody wrote that the sound of the reverb can be adjusted via a pot in the mains lead hatch. The pot is there but I couldn't hear any effect on the reverb.

- The tone section (bass and treble control; not displayed in below schematic) affects the signals from replay heads 1,2,3, from the spring reverb and from the chorus. The direct signal and the signal from the SoS head are not affected.

Regarding the RE-501: On harmony central somebody wrote the following:
The best feature that makes the 301 the best of the bunch is the sound-on-sound function. For those unfamiliar, it is a switch that allows you to listen to the whole of the tape whilst the delay effect is going on, a bit like a giant 15 second delay!! Play delicate chords, then as soon as you hear them start to repeat, harp some high notes. I cannot tell you how much fun you will have in hyperspace building soundscapes! With the other models, including the big brother RE501 the SOS does not cut it. The 501 has the SOS playhead in a different place so you only get a maximum of 5-6 seconds which is a real shame. The 301 is definately the most musical of all the space echos as I have tried all of them out.
Apparently the SoS head of the RE-501 is not at the end of the loop but somewhere after heads 1,2,3.

If you want endlessly repeated Sound-on-Sound the Korg SE-500 seems to be an option. Somebody at gearslutz writes:
But the SE-500 is very interesting indeed, It has this Sound on sound feature which switches off the erasehead so the tape becomes an endless loop. Just put some some nice/calm pattern, piano for example, on a loop and play it thru se SE-500, instant ambient machine!
I think switching off the erase head would be an easy modification of the RE-301 (Cut a cable, install a switch, done). I would expect however that the signal will be heaviliy degraded from one repetition to the next, as with each pass a new signal is recorded on top of the unerased tape.

I hope this provides the info you need :D
By the way how do you plan to use the Sound-on-Sound? As far as I understand this is mostly useful for solo players. Your nickname implies that you are doing something dubby. However in a typical dub setting these long echoes which are not synced with anything would mess up the timing completely.

Schematic-Roland-RE-301-m.jpg (63.4 KiB) Viewed 41526 times

dub vibe
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Post by dub vibe » Tue Dec 30, 2008 2:49 am

Hey interruptor, thanks a lot!!!!!!!!!

i could even see and hear a RE-301 in front of me with your explanation and lovely picture!
ya, thats a bit shame that no reverb is fed by the SOS. and bass and treble control too.

to get more repeats, maybe i could cover the erase-head with a piece of paper or something.
(has anyone tried like that with any roland echo? or any other machine?)
i am a bit afraid of cutting lines and connect something by myself... :no3:

>I would expect however that the signal will be heaviliy degraded
>from one repetition to the next, as with each pass a new signal is
>recorded on top of the unerased tape.

it could sound cool. i am not expecting a nice and clean repetition.
a gradually fading repetition might be cool too.

i thought about other echo machines, but the tape echo with spring reverb and SOS all in one is very attractive for me.

i also thought about buying 201 and cover the erase head with a piece of paper to make a loop,
but the position of replay head (would use the 1st head or 3rd as sos head, maybe?) wouldnt so good as 301...
im not sure if i am saying something even possible, but it just came to my mind.

i play the vibraphone alone using looper or live-recordiing/processing with beats or tracks and so on.
i play and use loop or even beats out of timing sometimes, so i dont really need to care about timing with tape loop.
the music i make is not really dub, but i am very much influenced by dub, and respect its sound and philosophy. :respect:
you can listen to some on myspace.

thanks again for your comment.
and also, still would love hear from 501 or 555 users!
of course from 301 users and 201 users too!!!

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Post by interruptor » Tue Dec 30, 2008 2:17 pm

Covering the erase head is something that could work. You can try that with any cassette tape recorder. Probably this will reduce the lifetime of your tape loop though (unless you use a really smooth surfaced material to cover the erase head).
I once disabled the erase head of a cassette recorder many years ago because I wanted to create a mix tape without having access to a dj-mixer. The results were not satisfying. If I remember correctly the signal recorded first on the tape lost most of the high frequencies and there were also some ugly switching noises. This would not necessarily be a problem in your case though.

By the way, I discovered some more in-depth info on the RE-301 and RE-501:

- Roland RE-301 service manual
- Roland RE-501 schematics and block diagram

These basically substantiate the findings in my last post.
- Additionally I saw that the pot in the mains lead hatch of the RE-301 sets the threshold level of a noise gate. This eliminates tape hiss and should particularly hide the faint noise that can be heard when the splice position of the tape loop passes the playback heads.
- The chorus and reverb on the re-301 are in fact routed in series not in parallel. When using the unit in reverb-only mode the signal is actually also passing the chorus circuit (a modulated bucket brigade delay). This will hardly be audible if the direct signal is muted and the chorus intensity pot is set to minimum.

Using a normal playback head of the RE-201 with diabled erase head may be an option too. You will hear an immediate echo (ca. 1 sec range) and then degraded echoes each time the same position of the tape passes the head again. As there is no SoS head you will never hear an undegraded long time echo.

I guess it all depends on how bad the degradation is. You should try with a tape cassette recorder and judge the potential yourself.


dub vibe
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Post by dub vibe » Wed Dec 31, 2008 2:23 am

yeah right, on the 201, the immediate echo is what i dont really want.
that the second repetition is already degraded is also not very nice.
seemingly, similar thing will happen with 501/555 too.
i want it like, first normal repeat and then it can be degraded.
so, 301 seems the only choice.

i will try the paper-covering thing on my tape deck. :boombox:

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