Home Brew Electronics - Hematoma Bass Overdrive/Preamp [traced]
- D-Day
- Mojo Book Buster
Labeled board: Labeled toggle: Numbered footswitch: Parts side: Solder side: A couple of misc gutshots: BOM
IC1 - 4558
Q1 - 2N5484
Q2 - MPSA18
D1 - silicon
D2 - silicon
D3 - LED
D4 - 1N4001
C1 - 1n
C2 - 4u7
C3 - 100u
C4 - 47u
C5 - 47n
C6 - .47u
C7 - ?
C8 - 50p
C9 - 4u7
C10 - .47u
R1 - 47K
R2 - 10M
R3 - 1K8
R4 - 100K
R5 - 1K
R6 - 10K
R7 - 12K
R8 - 1M
R9 - 10K
R10 - 10K
R11 - 10K
R12 - 47K
R13 - 1K5
R14 - 1M
R15 - 1K
R16 - 10K
R17 - 10K
R18 - 1K5
R19 - 1K
R20 - 1K
R21 - 1K
R22 - 1M
CONNECTIONS
PRE
1 - GND
2 - BP 2
3 - board
GAIN
1 - board
2 - board
TONE
1 - LEVEL 3
2 - TOGGLE 2
3 - board
LEVEL
1 - GND
2 - OUT
3 - TONE 1
BO FOOTSWITCH
1 - LED
2 - board
3 - LEVEL 2
4 - GND
5 - BP 6
6 - OUTPUT JACK TIP
8 - bypass
9 - bypass
BP FOOTSWITCH
1 - CIRCUIT IN
2 - PRE 2
3 - LED
4 - INPUT JACK TIP
5 - BO 5
6 - GND
7 - bypass
8 - bypass
Never degooped or took part in an RE before so let me know if I've done something wrong or have not been thorough enough.
- bubstance
- Solder Soldier
Information
- D-Day
- Mojo Book Buster
Oh duh! I wrote that down and forgot to include it. Thanks for reminding me.
PRE = B100K
LEVEL = B100K
GAIN = B500K
TONE = B10K
PRE = B100K
LEVEL = B100K
GAIN = B500K
TONE = B10K
- D-Day
- Mojo Book Buster
Nice one! My girl leaves town tomorrow and I'll give it a good look then. And jeez the youtube videos for this thing paint it in a pretty bad light. People who have wielded overdrives with bass before should be able to get something real sweet out of this.
- pedalgrinder
- Cap Cooler
this is my thoughts hey bubstance great trace good one!!! if you added a charachter pot same as the tubezone. I found with bass it's excellent as it tightness the flabbyness of the distortion up. It would only take say a 1uf cap and a pot of the 2 distortion diodes and you can control how to tight so to speak the distortion is on the lower bass notes when used on a bass. Try you will see what i mean. Cheers
What's the best thing about fat chicks and scooters? There both fun to ride around until your mates find out!
- D-Day
- Mojo Book Buster
Sorry for the long interval guys. I have a very old dog who is just coming apart at the seams these days. If it's between my dog and YATS I'll make the same choice every time.
Okay, C7 is (or might as well be) 1uf. The only way I could get the gain right was to put the tone section before the second op-amp exactly as a regular TS. It also seems to sound better without the 1M from the base of Q2 (mpsa18) to VB. I decreased the 1.5K from pin 1 to 5 to 1K and preferred it. Lastly it seemed to sound best with .47 coming from the clipping arrangement to ground instead of VB. The whole thing works as you've drawn it Bub, but it sounds just like the original with these changes.
I have to give this thing back soon so if there's any info anybody'd like please let me know asap.
Okay, C7 is (or might as well be) 1uf. The only way I could get the gain right was to put the tone section before the second op-amp exactly as a regular TS. It also seems to sound better without the 1M from the base of Q2 (mpsa18) to VB. I decreased the 1.5K from pin 1 to 5 to 1K and preferred it. Lastly it seemed to sound best with .47 coming from the clipping arrangement to ground instead of VB. The whole thing works as you've drawn it Bub, but it sounds just like the original with these changes.
I have to give this thing back soon so if there's any info anybody'd like please let me know asap.
Hello,
I know this is an old thread, but I was looking into building this pedal.
I prefer having the part references and not only the values, so while I was checking the schematic I believe I found an error :
R13 - 1k5 connects on one side to C6 (0.47uF, in turn connected to VB), just like the schematic.
But the other side of R13, by tracing the PCB should connect to pin 2 of IC1, and not to junction R12/R11/D2/D3.
R13 and R12 are not connected together in any way. You can verify this looking at the copper side image.
So that might be why D-Day needed to make changes to make it work correctly.
This also means the stripboard version posted on tagboardeffects is incorrect.
Btw, thank you D-Day for the photos and values. Great job!
Dae.
I know this is an old thread, but I was looking into building this pedal.
I prefer having the part references and not only the values, so while I was checking the schematic I believe I found an error :
R13 - 1k5 connects on one side to C6 (0.47uF, in turn connected to VB), just like the schematic.
But the other side of R13, by tracing the PCB should connect to pin 2 of IC1, and not to junction R12/R11/D2/D3.
R13 and R12 are not connected together in any way. You can verify this looking at the copper side image.
So that might be why D-Day needed to make changes to make it work correctly.
This also means the stripboard version posted on tagboardeffects is incorrect.
Btw, thank you D-Day for the photos and values. Great job!
Dae.
- Attachments
-
- Schematic error
- Hematoma_err.png (4.9 KiB) Viewed 4171 times
Well I've been waiting for close to 2 weeks for an answer from bubstance with no response, so here is my redrawn and corrected schematic for the Hematoma with part references. I made the correction for R13, as well as added the pinout for both footswitch so hopefully it makes it clearer for everyone. I also added the LEDs, as they were on the original PCB. Let me know if I missed anything, or if you have any questions.
@bubstance, if you want your nickname removed from it, let me know and I'll change it.
Daemons
@bubstance, if you want your nickname removed from it, let me know and I'll change it.
Daemons
- Silver Blues
- Breadboard Brother
I built one of these using the Tagboard vero layout and it works just fine for me. It does have a very dark sound to it (expected, I was informed this was the natural case) and I made a few mods to the tone control and whatnot and it sounds good.
- D-Day
- Mojo Book Buster
daemons found an error!
5 - should be BP 5
Can a mod please edit?
5 - should be BP 5
Can a mod please edit?
D-Day wrote: BO FOOTSWITCH
1 - LED
2 - board
3 - LEVEL 2
4 - GND
5 - BP 6
6 - OUTPUT JACK TIP
8 - bypass
9 - bypass
- D-Day
- Mojo Book Buster
Thank you daemons!!!daemons wrote:Well I've been waiting for close to 2 weeks for an answer from bubstance with no response, so here is my redrawn and corrected schematic for the Hematoma with part references. I made the correction for R13, as well as added the pinout for both footswitch so hopefully it makes it clearer for everyone. I also added the LEDs, as they were on the original PCB. Let me know if I missed anything, or if you have any questions.
@bubstance, if you want your nickname removed from it, let me know and I'll change it.
Daemons
- Manfred
- Tube Twister
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I made a PCB-clone from the first version for my private use:
I don't know if the dimensions matches the original size, because a created it form shots.
It is not verified in practice, but verified by the SprintLayout6 trace function. SprintLayout6:
I don't know if the dimensions matches the original size, because a created it form shots.
It is not verified in practice, but verified by the SprintLayout6 trace function. SprintLayout6: