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) and here (link) from 2017 and a 2019 BOM from Weiss (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) and a link to a suitable resistor (link) at 1%, MF0207. To make life easier – I am going to share my own BOM as I build it but please note – there may be errors (link) and my BOM questions will be posted here (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 |