In today’s post, I am documenting my build of the Gyraf SSL. This blog wll be a bit like a build diary and I hope to increase my knowledge of electronics throughout this project.
On the hunt for a G-Comp, I realised they were out of budget. Gyraf’s kept coming up as a decent clone and so, I started to explore my own build on the cheap. I managed to source matched DBX 202 Black Can VCAs from an old console at £25 a pop which I thought would be perfect for a build.
I then identified the current revision of the board and locations where to purchase them from. In this case, Pusherman looks like a good source for the UK.
I then found the Gyraf BOM and resource pack from Mikael (link) and looked into components. The problem I had with these BOMs are that they are vague. For example, in this project, I decided to start with something simple – resistors and then work my way up. Immediately, I had to scratch my head. I needed to understand the tolerance and wattage. Thankfully, a decent answer can be found here (link). Being UK based, I am going to build a BOM for CPC.Farnell as they are a trusted supplier of precision parts. It dawned on me that I then should find a more detailed BOM and came across Greg’s BOM list (link). While some of the parts will have changed – what a starting point! In relation to this, the 0.25 watts have modern replacements at 0.6 watts. Time to ask my first question (link).
For quick answers in the huge GSSL help thread, in Google, you can use site:groupdiy.com and then your query to pinpoint an answer quickly.
To begin, lets look at the resistors. These can be places in any direction. Due to using original cans, I need to pay attension to %-markings. For the actual type, I’m going for 1% but 5% sounds like it should be fine and 1/4 watt (0.25 W).
As tedious as this is – I have counted the resistors from the new revision 7 board – I’ll update this as I actually build it but for ordering – this is useful.
| Resistor Value | Main PCB | Control PCB | Total | Location |
|---|---|---|---|---|
| 10R | 2 | 0 | 2 | Under large PSU caps |
| 47R | 2 | 0 | 2 | Bottom Right |
| 68R | 2 | 0 | 2 | VCA |
| 100R | 7 | 0 | 7 | Bottom left/mid-left, near Output and between VCA output and Sidechain |
| 120R | 2 | 0 | 2 | VCA |
| 470R | 5 | 0 | 5 | Bottom left, near Output. Bottom right. |
| 820R | 0 | 1 | 1 | Cable area |
| 1K | 6 | 1 | 7 | VCA (4 & Outside Bottom 2). Control (right) |
| 2K | 1 | 0 | 1 | Right, near 10 pin header |
| 2K7 | 0 | 1 | 1 | Cable area |
| 3K9 | 3 | 0 | 1 | VCA (2) + Sidechain |
| 8K2 | 0 | 1 | 1 | Cable area |
| 10K | 10 | 0 | 1 | Near Diodes (1) Output (4) VCA (4) Sidechain (1) |
| 15K | 5 | 0 | 2 | Sidechain (1) Outside top VCA (2) Output (2) |
| 20K | 3 | 0 | 1 | Near diodes (3) |
| 22K | 8 | 0 | 8 | Top Left Input |
| 27K | 0 | 1 | 1 | Cable area |
| 33K | 1 | 0 | 1 | Diodes |
| 47K | 6 | 0 | 1 | Output, outside of VCA right. |
| 56K | 1 | 0 | 1 | Between VCA and sidechain |
| 68K | 0 | 1 | 1 | Cable area |
| 82K | 0 | 1 | 1 | Cable area |
| 91K | 0 | 1 | 1 | Right hand side |
| 100K | 3 | 0 | 1 | Sidechain |
| 127K | 0 | 0 | 0 | |
| 180K | 0 | 1 | 1 | Near release |
| 220K | 1 | 0 | 1 | Sidechain |
| 270K | 0 | 3 | 3 | Between release & attack tatio |
| 470K | 1 | 0 | 1 | Diodes/header |
| 510K | 0 | 1 | 1 | Cable area |
| 560K | 0 | 1 | 1 | Near attack |
| 620K | 1 | 1 | 2 | Sidechain, Control board, cable area |
| 750K | 0 | 1 | 1 | Control panel right |
| 1M | 3 | 0 | 1 | 10 Pin header (1) Outside botton of VCA |
| 1M2 | 0 | 2 | 2 | Near attack and left |
| 1M8 | 0 | 1 | 1 | Left |
| 3M3 | 1 | 0 | 1 | 10 Pin header |
| 3M9 | 0 | 1 | 1 | Left |
Notes: Difference between my table and the BOM.
100R, orignal list has 1 less.
10K, original has 4 less
15K, original has 2 less
27K, original has 2 more
47K, original has 1 more
100K , original has 1 less
127K, original has 1 more
| Diodes 5x 1n4148 | These are flow forward with black ring pointing to the tip with the arrow with a line across it. |
| Ceramic capacitors are 10p | |
| Ceramic capacitors are 22p | |
| Ceramic capacitors are 33p |