a legend is back...System-700 in eurorack

wendallsan · Post by **wendallsan** » Fri Aug 30, 2019 2:25 pm

Modulart_JP wrote:You can contact me privately via my website.
I'm sure we'll figure out what's wrong.

Thanks! I have followed up on your site as requested.

Modulart_JP · Post by **Modulart_JP** » Fri Sep 06, 2019 3:25 am

2 new modules in the SYS-700 family:
713 Gate Delay and 723 Analog Switch

I think there is not much interest in making a clone of the module 712.
However the voltage processor may be useful and that's why I added it to the 713 module.

The 715 Multimode Filters is coming soon...

LektroiD · Post by **LektroiD** » Fri Sep 06, 2019 9:24 am

Hi, I'm building the oscillator which asks for a 453K resistor. Using standard values, I am able to make 454K by either 24K + 430K in series, or 470K + 13MΩ in parallel. Is 454K adequate for this, or should I try to source the exact resistor?

Also... Does anyone know a good source for the subminiature SPDT switches (as used on the VCO) at a reasonable price in the UK?

Modulart_JP · Post by **Modulart_JP** » Fri Sep 06, 2019 11:00 pm

454K will do.

As for the SPDT switches, Farnell carry them:
https://export.farnell.com/multicomp/2m ... t%2Fsearch
Don't know if it's what you consider a good price though.

LektroiD · Post by **LektroiD** » Sat Sep 07, 2019 5:33 pm

Modulart_JP wrote:454K will do.

As for the SPDT switches, Farnell carry them:
https://export.farnell.com/multicomp/2m ... t%2Fsearch
Don't know if it's what you consider a good price though.

Thanks for this... I managed to find some from a company in Taiwan, just a case of waiting on shipping...

My next question is that 250pf capacitor... I have searched all over and cannot for the life of me find any, except those high voltage (>1KV) things used in power supplies, would these be ok, or should I use a 1000pf & 330pf in series to get 248.1pf? That's the closest I can get with standard values.

Modulart_JP · Post by **Modulart_JP** » Sat Sep 07, 2019 6:48 pm

Please refer to the Mouser cart.

LektroiD · Post by **LektroiD** » Mon Sep 09, 2019 11:23 pm

Modulart_JP wrote:Please refer to the Mouser cart.

Thanks, I hadn't noticed the link initially.

The next problem is the LM301, Unfortunately I've now run out of my limited stock. I don't see them in the mouser cart (I have also tried Farnell, RS as well as smaller companies like Bitsbox). I can only seem to find them on ebay or aliexpress, so I'm doubtful of the authenticity. Have these been discontinued? Is anyone managing to get these in the UK?

wendallsan · Post by **wendallsan** » Tue Sep 10, 2019 10:56 am

LektroiD wrote:The next problem is the LM301, Unfortunately I've now run out of my limited stock. I don't see them in the mouser cart (I have also tried Farnell, RS as well as smaller companies like Bitsbox). I can only seem to find them on ebay or aliexpress, so I'm doubtful of the authenticity. Have these been discontinued? Is anyone managing to get these in the UK?

I'm doing a build of several of these modules as well and have also had a bit of a challenge sourcing LM301's. I bought a bunch from China, and they all turned out bad, so apparently trying to score a deal on eBay is not the thing to do. I bought some OP07CPZ chips from Mouser in the US and these seem to have worked fine as drop-in replacements for LM301's in the modules I've tried them out in (including the mixer, the amp/E.F./integrator, S&H, and noise/ring mod modules). When my LM301's from China were causing problems, folks were telling me to replace them with 'pretty much any op amp' that had the same pinout, so it seems like the LM301 is not all the critical? If this is the case, I'd love to hear what acceptable subs could be used for folks having problems sourcing the LM301's. Also, the 3080's are a pain to find and are expensive to boot, which leaves me wondering if there are any acceptable replacements for those as well. I don't know enough electronics to know one opamp from another, other than looking at pinouts and curves in the graphs on the spec sheets for the IC's.

Here's a link to the OP07CPZ chips if anyone needs them:
https://www.mouser.com/ProductDetail/584-OP07CPZ

ringroad1 · Post by **ringroad1** » Tue Sep 10, 2019 11:14 am

In a brief test I did a while back LM13700 worked fine in the 24db VCF, although I had to do some convoluted wiring up to check 'cos the pinout is very different.

Not a UK/EU supplier but Tayda say they have loads of LM301. I've bought some from them in the past, I don't remember having any trouble (not much of an endorsement, I agree)

The impression I get is that the LM301 is fairly rubbish so I don't think there's any need to buy anything fancy.

Modulart_JP · Post by **Modulart_JP** » Tue Sep 10, 2019 8:19 pm

The next problem is the LM301, Unfortunately I've now run out of my limited stock. I don't see them in the mouser cart (I have also tried Farnell, RS as well as smaller companies like Bitsbox). I can only seem to find them on ebay or aliexpress, so I'm doubtful of the authenticity. Have these been discontinued? Is anyone managing to get these in the UK?

You can buy them from me.
They are available for sale in my shop.
Jameco has them too at a slightly better price.

LektroiD · Post by **LektroiD** » Fri Sep 13, 2019 5:01 am

I was looking at the 708A ring modulator, it seems that there were variants (possibly factory modded), the user manual shows one type, yet I found an image of one with 6 extra switched inputs, which looks really interesting...

Modulart_JP · Post by **Modulart_JP** » Fri Sep 13, 2019 7:55 pm

Does not look really genuine to me...
And I'm almost sure Roland would have done a far better job if it had been modded by them.

LektroiD · Post by **LektroiD** » Sat Sep 14, 2019 3:11 am

It was spotted in this sale: http://www.rlmusic.co.uk/rlm3/roland-system-700/

It seems the original 708A had the 4-way switches hardwired to the various oscillators in the synth. Looks like someone had the creative idea to add sockets in place of the hardwiring. It's an interesting configuration having the switchable inputs if you're playing a live sequence and you want to route another source into the RM without repatching. I guess that's another feature that made the System 700 so unique.

wendallsan · Post by **wendallsan** » Sun Sep 15, 2019 11:36 am

LektroiD wrote:It's an interesting configuration having the switchable inputs if you're playing a live sequence and you want to route another source into the RM without repatching.

This looks like fun. I immediately find myself thinking about this plus CV controlled switches for those inputs. I guess we could throw that together with a 708 and a couple 723's?

LektroiD · Post by **LektroiD** » Mon Sep 16, 2019 1:04 pm

wendallsan wrote:
LektroiD wrote:It's an interesting configuration having the switchable inputs if you're playing a live sequence and you want to route another source into the RM without repatching.
This looks like fun. I immediately find myself thinking about this plus CV controlled switches for those inputs. I guess we could throw that together with a 708 and a couple 723's?

I was initially thinking of modding the 708, rather than filling the cabinet with switch modules. The only issue is the PCB covering the blank area of the panel, so no room for a switch. I'm now thinking of maybe a 2HP breakout panel and a couple of 4 way slide switches.

Modulart_JP · Post by **Modulart_JP** » Tue Sep 17, 2019 3:12 am

2x 4 position slide switches and 8 jacks won't fit into 2HP...

LektroiD · Post by **LektroiD** » Fri Sep 20, 2019 2:44 pm

Calibrating the 703F VCF... I see no change on any of the poles when I test at the points indicated. I have my scope set to 50mV and all pots fully CCW. I am grounding the scope from the socket ground. Each pole is giving zero reading on the scope but rotating the trimmers from 0-100k has absolutely no effect on the scope reading.

The filter appears to work as expected with an audio input, but I would like to calibrate the individual poles properly.

Modulart_JP · Post by **Modulart_JP** » Sat Sep 21, 2019 7:31 am

Is your scope set to DC ?

LektroiD · Post by **LektroiD** » Sun Sep 22, 2019 12:56 am

Modulart_JP wrote:Is your scope set to DC ?

Yes, it is set to DC

Modulart_JP · Post by **Modulart_JP** » Sun Sep 22, 2019 8:57 pm

I have my scope set to 50mV and all pots fully CCW.

Set your scope to 5mV.

Frankly speaking, it does not make a difference and I kept those trimmers for each pole to be thorough, stay true to the original schematics.
The truth is that many filters in other Roland synths have a similar filter and they did omit those trimmers.
I think they realized it was not worth it.

If you can do it, fine.
If not, don't bother...

LektroiD · Post by **LektroiD** » Mon Sep 23, 2019 12:11 am

Modulart_JP wrote:
I have my scope set to 50mV and all pots fully CCW.
Set your scope to 5mV.

Frankly speaking, it does not make a difference and I kept those trimmers for each pole to be thorough, stay true to the original schematics.
The truth is that many filters in other Roland synths have a similar filter and they did omit those trimmers.
I think they realized it was not worth it.

If you can do it, fine.
If not, don't bother...

50mV was already too noisy to see a decent signal. I had better luck with a multimeter set to mV, but even then the voltage was reading in the + at the lowest setting of each pole. It already sounds really nice, so if it's not vital, I'll leave it as is.

I was looking at the manual and reading through the various modules, the Frequency to Voltage feature on the 714 looks interesting. Is this something that's likely to be looked at?

Also there is a two-channel phaser (720B) with a lot of really nice features, is this likely to be cloned in the near future?

LektroiD · Post by **LektroiD** » Mon Sep 23, 2019 8:06 am

Hi, I'm having a bit of difficulty with the 702 oscillator (so far I have built only one as I'm awaiting LM301s to arrive).

Firstly, the pitch is about an octave and a half too low, and I cannot calibrate it any higher, even when I set the range to 4 instead of 8, I still cannot get it to reach 440Hz. The scaling and range is perfect otherwise.

I am also experiencing something strange with the sync. When I run in a waveform, it sounds more like an atari punk console than a sync. I have attached an audio demonstration. Firstly set to W, then to S, then back to W with a different source frequency. I sweep through the pitch from 0-10 and back to 0 on each of the three examples.

Modulart_JP · Post by **Modulart_JP** » Tue Sep 24, 2019 3:38 am

I was looking at the manual and reading through the various modules, the Frequency to Voltage feature on the 714 looks interesting. Is this something that's likely to be looked at?

Great on paper, not so great in real life...

Also there is a two-channel phaser (720B) with a lot of really nice features, is this likely to be cloned in the near future?

Nothing you can't do with 2x 711's.
Because this is what the 720 basically is...
To be exact, the 720 is 2x 711's with the addition of a frequency shift pot for each phaser.
Have a look at the schematics and you'll see that's something you can easily add to the 711.
You could make a break-out 4HP module you put between 2x 711's.

Firstly, the pitch is about an octave and a half too low, and I cannot calibrate it any higher, even when I set the range to 4 instead of 8, I still cannot get it to reach 440Hz. The scaling and range is perfect otherwise.

So far, what did you do to troubleshoot it ?

I am also experiencing something strange with the sync. When I run in a waveform, it sounds more like an atari punk console than a sync. I have attached an audio demonstration. Firstly set to W, then to S, then back to W with a different source frequency. I sweep through the pitch from 0-10 and back to 0 on each of the three examples.

What your scope shows you ?

The very last (and final) additions to the SYS-700 series are:
- 715 Multimode Filters (available by the end of this week)
- 717 Pulse Shaper (from the 717 Analog Sequencer), available as pre-order
- 717 Analog Sequencer: HUGE project, available as pre-order
Soon I will create a thread for that guy alone.

LektroiD · Post by **LektroiD** » Thu Sep 26, 2019 3:52 pm

Modulart_JP wrote: So far, what did you do to troubleshoot it ?

Nothing, other than checking over component values.
Which waveform is best to use to check frequency? It doesn't say which waveform output to use in the calibration procedure.

Also, what are the test points for, I have added test point terminals, but these are not mentioned in the calibration.

Modulart_JP wrote:
I am also experiencing something strange with the sync. When I run in a waveform, it sounds more like an atari punk console than a sync. I have attached an audio demonstration. Firstly set to W, then to S, then back to W with a different source frequency. I sweep through the pitch from 0-10 and back to 0 on each of the three examples.
What your scope shows you ?

I'm at college through the week so I don't have access to my workshop, what in particular should i be looking for on a scope reading, and what scope settings?

Modulart_JP wrote:The very last (and final) additions to the SYS-700 series are...

So no 721 (2ch. Audio Delay)? If it's anything like the System 100m, the system 700 audio delay should be a really nice analogue stereo chorus.

wendallsan · Post by **wendallsan** » Thu Sep 26, 2019 5:56 pm

Modulart_JP wrote:The very last (and final) additions to the SYS-700 series are:
- 715 Multimode Filters (available by the end of this week)
- 717 Pulse Shaper (from the 717 Analog Sequencer), available as pre-order
- 717 Analog Sequencer: HUGE project, available as pre-order
Soon I will create a thread for that guy alone.

Oh yeah, so you ARE gonna release a sequencer!

I guess my pharmasonic builds are not done yet!

Will it be 12 steps like the original or something more 'typical'?

Can't wait to see what this will look like.

MUFF WIGGLER

MUFF WIGGLER

a legend is back...System-700 in eurorack