my preference is really for a classic bulky linear adapter - that's what the device was originally designed for, after all. people who swap theirs for some generic, more efficient SMPS probably don't realize that those come with the tradeoff of producing more ripple/noise so they just wear out the capacitors faster, as they weren't selected with this in mind.

that being said, switch-mode adapters differ of course and the boss one might be of decent quality, in fact for that price you better hope it is. but it's still not what the device was originally designed for.

auron wrote on 2021-02-07, 06:53:

my preference is really for a classic bulky linear adapter - that's what the device was originally designed for, after all. people who swap theirs for some generic, more efficient SMPS probably don't realize that those come with the tradeoff of producing more ripple/noise so they just wear out the capacitors faster, as they weren't selected with this in mind.

that being said, switch-mode adapters differ of course and the boss one might be of decent quality, in fact for that price you better hope it is. but it's still not what the device was originally designed for.

Considering the fact that these modern switching Roland PSUs are sold for use with all sorts of gear, at least some of which is meant for the recording industry, one can indeed hope that Roland specced to them to a high degree of quality (including low noise and ripple).

That said, if the devices that these PSUs are meant to power run the received DC current through a linear regulator to begin with, I imagine that ripple would be taken care for everything that is fed by the said regulator . Please correct me on this if necessary.

Additionally, AFAICR, the original linear PSUs for these modules were unregulated, so wouldn't they be even worse in terms of ripple than high quality switching regulated PSUs ?

darry wrote on 2021-02-07, 07:17:

That said, if the devices that these PSUs are meant to power run the received DC current through a linear regulator to begin with, I imagine that ripple would be taken care for everything that is fed by the said regulator . Please correct me on this if necessary.

i've seen a generic SMPS cause massive amounts of interference on the video output of an SNES, and that has a regulator inside as well.

auron wrote on 2021-02-07, 07:42:

darry wrote on 2021-02-07, 07:17:

That said, if the devices that these PSUs are meant to power run the received DC current through a linear regulator to begin with, I imagine that ripple would be taken care for everything that is fed by the said regulator . Please correct me on this if necessary.

i've seen a generic SMPS cause massive amounts of interference on the video output of an SNES, and that has a regulator inside as well.

I imagine those were extremely crappy, badly designed, cost-cut SMPS . Hopefully, we are talking about the bottom of the barrel.

It would be nice if someone who has the necessary equipment could run some comparison tests between some generic and purportedly good Roland branded ones (both switch mode and linear), in terms of both ripple and RF emissions when under load .

darry wrote on 2021-02-07, 06:48:

But, the official Roland US recommendation for the SC-155 was the PSB-1U whose european version was replaced by the PSB-230EU, AFAICT .

Hmm, it seems like the PSB-230EU has 9V and 2000 mA. On the other hand, the PSA-230S appears to have 9V and 500 mA.

Looking at the back of my SC-155, it states that 9V and 500 mA should be used. Seeing as how both of these (European) adapters were not really meant for the Sound Canvas, wouldn't it be safer to go with the one whose specs match the SC-155 more closely?

Joseph_Joestar wrote on 2021-02-07, 08:02:

darry wrote on 2021-02-07, 06:48:

But, the official Roland US recommendation for the SC-155 was the PSB-1U whose european version was replaced by the PSB-230EU, AFAICT .

Hmm, it seems like the PSB-230EU has 9V and 2000 mA. On the other hand, the PSA-230S appears to have 9V and 500 mA.

Looking at the back of my SC-155, it states that 9V and 500 mA should be used. Seeing as how both of these (European) adapters were not really meant for the Sound Canvas, wouldn't it be safer to go with the one whose specs match the SC-155 more closely?

AFAIK, in theory if both have over current protection, that should kick in lat a lower current on the lower specced unit . Again, AFAIK, that should really only come into play if a failure mode causing something like a short were to happen inside your SC-155 .

I know that the PSA-120S and PSB-120 have over current protection (written in/on the box) and I would guess that the PSA-230S and PSB-230EU are the Euro version of those, so I imagine they would too . Roland and Boss web sites do not say anything on the subject, AFAICT .

Incidentally, in the US, the 500mA PSA-120S is the Roland recommended replacement PSU for the MT-32 whose original PSU was rated at 650mA ! Either Roland know something we do not or their recommendations are to be taken with a grain of salt.

At the end of the day, my guess is that if the PSA-230S is indeed current limited at 500mA or so, it is likely safer to limit damages in the case of the SC-155 having a specific over current failure mode . Excluding that scenario, the PSB-230EU should work just as well in day to day use, with the added potential benefit of being re-usable in the future with higher current devices .

That is my 2 cents worth of an opinion .

auron wrote on 2021-02-07, 07:42:

darry wrote on 2021-02-07, 07:17:

That said, if the devices that these PSUs are meant to power run the received DC current through a linear regulator to begin with, I imagine that ripple would be taken care for everything that is fed by the said regulator . Please correct me on this if necessary.

i've seen a generic SMPS cause massive amounts of interference on the video output of an SNES, and that has a regulator inside as well.

I've ran in to that too, but a lot of those cheap PSUs are complete garbage with massive amounts of ripple. When they can be had individually for £3 including shipping from China, you know they're not going to be quality.

My rules for PSUs for old consoles and gear are to buy from legit electronics suppliers that supply to industry, buy ones from known PSU manufacturers, and try to choose ones with low amounts of ripple in their specs. If I can't find a datasheet for it, I don't buy it. That rules out virtually everything from ebay and everything suspiciously cheap. Rather irritatingly, companies supplying replacement PSUs for their gear, such as Boss/Roland, are rather bad at providing detailed datasheets for their parts. That always makes me suspicious that they might be cheaping out slightly, although this might not be the case at all.

darry wrote on 2021-02-07, 15:15:

I know that the PSA-120S and PSB-120 have over current protection (written in/on the box) and I would guess that the PSA-230S and PSB-230EU are the Euro version of those, so I imagine they would too . Roland and Boss web sites do not say anything on the subject, AFAICT .

Yeah, it really surprised me that there were no detailed specs on the Roland/Boss website. I had to either go to third-party resellers or look for a picture where the sticker is clearly visible on the adapter in order to find the relevant info.

I guess I'll go with the PSA-230S then. For the price they are asking, I really hope the adapter uses high quality components.

Joseph_Joestar wrote on 2021-02-07, 17:49:

darry wrote on 2021-02-07, 15:15:

I know that the PSA-120S and PSB-120 have over current protection (written in/on the box) and I would guess that the PSA-230S and PSB-230EU are the Euro version of those, so I imagine they would too . Roland and Boss web sites do not say anything on the subject, AFAICT .

Yeah, it really surprised me that there were no detailed specs on the Roland/Boss website. I had to either go to third-party resellers or look for a picture where the sticker is clearly visible on the adapter in order to find the relevant info.

I guess I'll go with the PSA-230S then. For the price they are asking, I really hope the adapter uses high quality components.

Yet another option is getting a North American version of one of these PSUs . AFAIK, they are all all 100v to 240v 50Hz/60Hz capable (my PSB-120 and PSA-120S are, according to the writing on them). Then you would just need a plug adapter. I am only suggesting this because it might actually be cheaper for you .

As a curiosity, the PSB-120 can be had in Canada for 29.99 CAN$ whereas it is 29.99 US$ in the USA . Depending on shipping costs and duties, it may actually be cheaper your you to get on abroad. If you know people in places where these are significantly cheaper, it may be worth asking one these people to buy one and ship it to you .

Joseph_Joestar wrote on 2021-02-07, 08:02:

darry wrote on 2021-02-07, 06:48:

But, the official Roland US recommendation for the SC-155 was the PSB-1U whose european version was replaced by the PSB-230EU, AFAICT .

Hmm, it seems like the PSB-230EU has 9V and 2000 mA. On the other hand, the PSA-230S appears to have 9V and 500 mA.

Looking at the back of my SC-155, it states that 9V and 500 mA should be used. Seeing as how both of these (European) adapters were not really meant for the Sound Canvas, wouldn't it be safer to go with the one whose specs match the SC-155 more closely?

Using them on a Sound Canvas is fine. You won't be able to find the correct adapter as stated in the manual from Roland because the old adapters are all out of production. As long as the polarity, output voltage, mA, and plug size match, you're good to go. Higher mA than mentioned on unit/in manual does not actually matter, by the way.

Oh, and just get the US version of that adapter if you're in the US...

The new power adapter and audio cable just arrived. The buzzing is much fainter now but not completely gone. Maybe one of the capacitors inside the SC-155 needs replacing. I'll check up on that the next time I open it up.

EDIT - quick update. Turns out I only get the buzzing when the volume dial on the SC-155 is either at the middle position or lower than that. On the other hand, if I move the volume dial completely to the right (max) the buzzing is gone. Very strange.

I made a couple of recordings to showcase the buzzing issue. Both files were recorded with the SC-155 powered on and directly connected to the Line In of an X-Fi Titanium. Nothing in between.

Recording #1 - SC-155 volume knob exactly at half. Faint buzzing/ticking noise present, mostly on the left channel.

Recording #2 - SC-155 volume knob at maximum (turned completely to the right). No buzzing/ticking noise present, just the usual white noise.

My best guess is that a faulty capacitor might be causing the buzzing, but I'm not sure why it goes away when the volume is maxed out. Any ideas?

Joseph_Joestar wrote on 2021-02-10, 13:12:

I made a couple of recordings to showcase the buzzing issue. Both files were recorded with the SC-155 powered on and directly co […]
Show full quote

I made a couple of recordings to showcase the buzzing issue. Both files were recorded with the SC-155 powered on and directly connected to the Line In of an X-Fi Titanium. Nothing in between.

Recording #1 - SC-155 volume knob exactly at half. Faint buzzing/ticking noise present, mostly on the left channel.
Buzz.mp3

Recording #2 - SC-155 volume knob at maximum (turned completely to the right). No buzzing/ticking noise present, just the usual white noise.
No_Buzz.mp3

My best guess is that a faulty capacitor might be causing the buzzing, but I'm not sure why it goes away when the volume is maxed out. Any ideas?

Wouldn't it make sense if it was an issue with the volume pot being dirty?

Oetker wrote on 2021-02-10, 13:16:

Wouldn't it make sense if it was an issue with the volume pot being dirty?

That might just be it.

I'll see if I can get in there with some contact cleaner.

Hey this place is awesome! This thread is how I found vogons. Anyway I will soon have a SC-155 and was wondering what sort of maintenance I can expect like replacing the battery. I have a ridiculous setup and currently have a mt32, sc55mk2, sc88, and Alexis nano synth. I got interested to get an older sound canvas and learned about the sc-155 which looked cool to me with the faders so I had to go looking for one. I also ordered an older sound canvas in the usual form factor. I plan to setup some of these at my brothers place because he really likes old dos games. I mostly like playing midi tracks through them and connecting midi controllers to them. I have a large mixer and a midi split box so I can play midi back though up to 4 modules at once and easily compare how they sound. It is a lot of fun and the mt32 has an interesting character. The nano synth is also pretty neat. Anyway now that I found this forum I’m sure I’ll dig around and find more fun stuff. I haven’t tried recording the modules yet but I can multitrack up to 32 channels so my setup would be ideal for it. My mixer is an Allen and Heath qu32, it’s awesome and I’m pretty sure I could get great recordings from the modules with it.

Geddon wrote on 2021-10-30, 19:15:

Hey this place is awesome! This thread is how I found vogons. Anyway I will soon have a SC-155 and was wondering what sort of maintenance I can expect like replacing the battery.

Welcome! I didn't even realize this thread of mine was picked up by Google. Pretty surreal, but I'm glad it introduced someone new to the Vogons community.

Concerning SC-155 maintenance, I'd definitively suggest getting a new power adapter if your device didn't ship with the original one. You'll get cleaner output that way.

It might also be a good idea to take a look at the capacitors on the PCB while you're changing the battery. These things are almost 30 years old now, so it's possible that some of them might be bulging or leaking.

I realize this post is on an old thread. I just changed out the CR2032 battery and took some pictures.
There are five screws to remove to get to the battery without pulling connectors: 3 on bottom and 2 on back. Arrows point to them in the pictures.
The service manual shows which ones. Service and Owner manuals are still posted here as of 2023: https://www.synthxl.com/roland-sc-155/