Enclosure not stated · 5 knobs
Exar HM-02 Heavy Metal
Based on the Exar HM-02 Heavy Metal
- Category
- Distortion
- Build
- Vero· 25×32· 50 cuts, 24 links
- Layout
- Unverified · no build reported at Dirtbox Layouts yet
- Tags
- Distortion, Exar
From the post
As many others, I thought this was just a clone or a close derivate to the Boss HM2. We couldn't be more wrong. Vitali from drunk beaver pedals opladed a schematic for it and it reveals a quite an interesting circuit. The distortion section resembles Boss DS2 with a discrete op amp and hard clipping diodes. The 3-band eq section is fairly unique. Mid control is basically a volume control for the raw unfiltered signal. Low is built around a 3rd order Sallen key filter and the High control is driven with an active dual high pass filter not dissimilar to one of the filters found in EHX Knockout.
The layout turned out quite big with all these transistors and op amps so it is intended for a BB enclosure.
Schematic
This is a board layout, a drawing of where each part goes, and the post may link the schematic it was drawn from. Open the layout at Dirtbox Layouts. No KiCad fragment has been drawn for this circuit yet.
Parts list 46 rows
Report a wrong parseGot parts in a drawer? See what you can build with them.
Check before you build · 1 value the reader of this layout was not sure of
- 14K horizontal at G8-G10 (left of centre, above IC2): printed clearly, unusual value
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 15 | ||||
| ×2 | 1M | 1M | read from the layout by eye | |
| ×1 | 470K | 470k | read from the layout by eye | |
| ×2 | 220K | 220k | read from the layout by eye | |
| ×4 | 100K | 100k | read from the layout by eye | |
| ×4 | 22K | 22k | read from the layout by eye | |
| ×1 | 16K | 16k | read from the layout by eye | |
| ×1 | 15K | 15k | read from the layout by eye | |
| ×1 | 14K | 14k | read from the layout by eye | |
| ×1 | 12K | 12k | read from the layout by eye | |
| ×15 | 10K | 10k | read from the layout by eye | |
| ×5 | 4.7K | 4.7k | read from the layout by eye | |
| ×4 | 2.2K | 2.2k | read from the layout by eye | |
| ×1 | 1.5K | 1.5k | read from the layout by eye | |
| ×2 | 1K | 1k | read from the layout by eye | |
| ×1 | 220Ω | 220 | read from the layout by eye | |
| Capacitors 13 | ||||
| ×2 | 100pF | 100p | read from the layout by eye | |
| ×1 | 470pF | 470p | read from the layout by eye | |
| ×4 | 1nF | 1n | read from the layout by eye | |
| ×1 | 4.7nF | 4.7n | read from the layout by eye | |
| ×2 | 10nF | 10n | read from the layout by eye | |
| ×2 | 22nF | 22n | read from the layout by eye | |
| ×4 | 47nF | 47n | read from the layout by eye | |
| ×1 | 100nF | 100n | read from the layout by eye | |
| ×2 | 220nF | 220n | read from the layout by eye | |
| ×2 | 470nF | 470n | read from the layout by eye | |
| ×5 | 10uF | 10u | electrolytic; read from the layout by eye | |
| ×2 | 47uF | 47u | electrolytic; read from the layout by eye | |
| ×2 | 100uF | 100u | electrolytic; read from the layout by eye | |
| Diodes 2 | ||||
| ×4 | 1N4148 | 1N4148 | D1-D4; read from the layout by eye | |
| D5 | 1N5817 | 1N5817 | read from the layout by eye | |
| Transistors 9 | ||||
| Q1 | 2SK117 | 2SK117 | JFET; read from the layout by eye | |
| Q2 | BC550B | BC550B | read from the layout by eye | |
| Q3 | 2SK117 | 2SK117 | JFET; read from the layout by eye | |
| Q4 | 2SK117 | 2SK117 | JFET; read from the layout by eye | |
| Q5 | BC550B | BC550B | read from the layout by eye | |
| Q6 | BC560B | BC560B | read from the layout by eye | |
| Q7 | BC550B | BC550B | read from the layout by eye | |
| Q8 | BC550B | BC550B | read from the layout by eye | |
| Q9 | BC547B | BC547B | read from the layout by eye | |
| ICs 2 | ||||
| IC1 | JRC4558D | JRC4558D | read from the layout by eye | |
| IC2 | JRC4558D | JRC4558D | read from the layout by eye | |
| Potentiometers 5 | ||||
| Dist | B220K | B220k | Potentiometer | read from the layout by eye |
| High | B10K | B10k | Potentiometer | read from the layout by eye |
| Mid | B10K | B10k | Potentiometer | read from the layout by eye |
| Low | B10K | B10k | Potentiometer | read from the layout by eye |
| Level | B50K | B50k | Potentiometer | read from the layout by eye |