Hi,
As the title says, I want to try to recreate the Roland SVC-350 Vocoder. My reason for choosing the svc are that it sounds great from the videos I've seen. Also, I imagine a ton of satisfaction from putting a few hundred dollars to build something myself that goes for >$1000 on the market. I'm looking to this forum to help me with some of the challenges of this project.
My initial plan is to put together the part list on octopart (this involves figuring out what goes where). From there I'll try to piece together the schematic, one section at a time, possibly on a lab bench with an oscilloscope. I'll work towards getting a functional 1 channel vocoder and from there i'll drop in the other 10 channels. I'm not so sure I care about the ensemble section. I think I may outsource a PCB manufacturer (i'm familiar with making eagle files-it's part of my day job).
The inital challenge I see is getting all the right components in the right spots. Does the schematic give enough information. Possibly one of you might know how to identify which Diode or Transistor goes where (since there are only a handful of semiconductors in the parts list it may be obvious to someone with more knowledge than me as to which part goes where). Here's the service manual: http://soundprogramming.net/manuals/effects/Roland_SVC-350_ServiceNotes.pdf
Also, what are some of the other foreseen challenges this project poses?
As the title says, I want to try to recreate the Roland SVC-350 Vocoder. My reason for choosing the svc are that it sounds great from the videos I've seen. Also, I imagine a ton of satisfaction from putting a few hundred dollars to build something myself that goes for >$1000 on the market. I'm looking to this forum to help me with some of the challenges of this project.
My initial plan is to put together the part list on octopart (this involves figuring out what goes where). From there I'll try to piece together the schematic, one section at a time, possibly on a lab bench with an oscilloscope. I'll work towards getting a functional 1 channel vocoder and from there i'll drop in the other 10 channels. I'm not so sure I care about the ensemble section. I think I may outsource a PCB manufacturer (i'm familiar with making eagle files-it's part of my day job).
The inital challenge I see is getting all the right components in the right spots. Does the schematic give enough information. Possibly one of you might know how to identify which Diode or Transistor goes where (since there are only a handful of semiconductors in the parts list it may be obvious to someone with more knowledge than me as to which part goes where). Here's the service manual: http://soundprogramming.net/manuals/effects/Roland_SVC-350_ServiceNotes.pdf
Also, what are some of the other foreseen challenges this project poses?
first challenge - sourcing custom parts from that far back. ROMs, programmed CPUs, any DSP, and ASICs will likely not be there in stock. There are certainly many old synth parts from that era that are no longer available. Especially custom hybrid ICs.
Your link does not work right for me. It gets me to a web site, and I can select effects, then Roland, the SVC350, but when I click on it, it just delivers me back a couple pages.
Can you provide a direct link to the service manual? The schematic ought to identify every part.
Your link does not work right for me. It gets me to a web site, and I can select effects, then Roland, the SVC350, but when I click on it, it just delivers me back a couple pages.
Can you provide a direct link to the service manual? The schematic ought to identify every part.
Hey Enzo, Thanks for the reply. As far as digital ICs and programmed CPUs I was hoping I can avoid all that stuff and just streamline the main vocoder aspect of the design (if possible). The direct link doesn't seem to be working but try Roland SVC-350 Vocoder | Sound Programming
and then click "Service Manual" right in the middle of the page.
and then click "Service Manual" right in the middle of the page.
yeah, I click that and it takes me to a earlier page in the tree.
The digital stuff may be part and parcel of the system though, that is why we need a good schematic.
The digital stuff may be part and parcel of the system though, that is why we need a good schematic.
I realized I said service manual but it's actually the Service Notes,not the manual. I'm looking at page 7 of that pdf and I see a schematic with a parts list on page 8. Are you looking at the same thing? Thanks.
I wasn't until just now, at my other office the computer could not get to the files. I could download it here though, so I now have the schematic.
OK, you are in luck, this is old enough it is just a huge pile of basic analog circuits, no hybrids or customs.
All the parts are identified on the schematic, and there is a parts layout on the previous page.
OK, you are in luck, this is old enough it is just a huge pile of basic analog circuits, no hybrids or customs.
All the parts are identified on the schematic, and there is a parts layout on the previous page.
Great to hear!
Now how about the transistors/diodes? I see how they are labelling the ICs but I have yet to find where they denote which specific diode goes where, for instance.
Also, would it be easier to just get ready-to-use power supply? Although, it looks like they are using a few different voltages so I suppose you would need more than one.
I'm anticipating some of these old vintage parts are gonna be difficult to acquire. I have no problem using one op amp over another if it means replacing a $20 op amp with a $0.20 that is functionally similar. My main goal here is to make an Analog Vocoder that's closest to the SVC-350.
Now how about the transistors/diodes? I see how they are labelling the ICs but I have yet to find where they denote which specific diode goes where, for instance.
Also, would it be easier to just get ready-to-use power supply? Although, it looks like they are using a few different voltages so I suppose you would need more than one.
I'm anticipating some of these old vintage parts are gonna be difficult to acquire. I have no problem using one op amp over another if it means replacing a $20 op amp with a $0.20 that is functionally similar. My main goal here is to make an Analog Vocoder that's closest to the SVC-350.
I guess I am unsure the question. I mean there are diodes in the power supply, but out in the circuit, unless they are zeners, are they not all the same types? The little ones will be like 1N4148 or equivalent
Thanks for the reply Enzo. So my question to you is where do you get '1N4148' from? The parts list says under diode: 1S2473 or equivalent. Maybe that's what you meant? I know the 1N4148 is common so maybe they are equivalent.
What I was really asking was about the transistors (since there seems to be a larger list of transistors used in this circuit). How do I tell if a given transistor, let's say Q44 near the bottom-left corner of the schematic, is 2SA733-P or 2SD880-0 or any of the other numerous transistors that are listed in the parts list?
Thanks
What I was really asking was about the transistors (since there seems to be a larger list of transistors used in this circuit). How do I tell if a given transistor, let's say Q44 near the bottom-left corner of the schematic, is 2SA733-P or 2SD880-0 or any of the other numerous transistors that are listed in the parts list?
Thanks
I got it because it is the most common small diode in western circuitry, the Asian equivalent is equally as common over there on that side of the ocean.
I cannot open the link from here. So in general 2SA/SB numbers are PNP and 2SC/SD are NPN.
I cannot open the link from here. So in general 2SA/SB numbers are PNP and 2SC/SD are NPN.
I see now, that's helpful.
In one corner of the main schematic it has a little section that simply says:
There are a few instances where an mpn is written next to a transistor. However, for the most part they are unlabelled. Am I to assume that every unmarked instance of an NPN is going to be the 2SC945-P and so on according to the chart above?
In one corner of the main schematic it has a little section that simply says:
Code:
transistors: PNP 2SA733-P
NPN 2SC945-P
FET 2SK30A-GRThere are a few instances where an mpn is written next to a transistor. However, for the most part they are unlabelled. Am I to assume that every unmarked instance of an NPN is going to be the 2SC945-P and so on according to the chart above?
That is what the chart means, yes. If it is not spelled out, it is generally understood that the chart means "unless otherwise noted".
Great, thanks! This is starting to make more sense now. I'm trying to figure out the power section. To me, it looks like the majority of the circuit is being powered by +/-15V (I'm assuming that's what +B1 and -B1). And also, it seems that there are two versions of this unit - 1 designed for a 100/117V Power Supply and 1 designed for a 220/240V Power (Just trying to wrap my head around the schematic).
So for the most part, where I see a black arrow up that means +15V, and a black arrow down means -15V, correct? I also see a +/-22V and a +/-7V but would those only be applied at the location they are mentioned?
So for the most part, where I see a black arrow up that means +15V, and a black arrow down means -15V, correct? I also see a +/-22V and a +/-7V but would those only be applied at the location they are mentioned?
Power Question
Here is a picture of the power supply on the schematic. I'm trying to figure out what +/-B2 and +B3 are supposed to be.
I've run a few a SPICE simulations on this section.
Here's the Voltage Curves of the three nodes (Green: +B2; Blue: +B3; Red: -B2) This picture has no load resistance. However, with a 1k load on each node the curves have a similar shape but peak around +/-12V.
If someone could help provide some insight that would be greatly appreciated. I should also note that the +/-B2 and B3 are only used in the "output" section of the circuit (on the opamp that is before the vocal amp output).
Here is a picture of the power supply on the schematic. I'm trying to figure out what +/-B2 and +B3 are supposed to be.
I've run a few a SPICE simulations on this section.
Here's the Voltage Curves of the three nodes (Green: +B2; Blue: +B3; Red: -B2) This picture has no load resistance. However, with a 1k load on each node the curves have a similar shape but peak around +/-12V.
If someone could help provide some insight that would be greatly appreciated. I should also note that the +/-B2 and B3 are only used in the "output" section of the circuit (on the opamp that is before the vocal amp output).
B1 is 15v, those B2 and B3 are mainly just isolated nodes of the 15v. They will be a small amount lower in voltage. Note B3 is just one diode drop lower than B2. And B2 is a diode drop and a transistor junction drop less than B1. So B1-2-3 might be something like 15-14-13v. If you have your 15v supplies, then just duplicate the circuit as you see it, and your B2,B3 will fall into place on their own.
- Status
- Not open for further replies.