# First Build report - M800



## TravisM (Jan 1, 2022)

I wanted a MIAB pedal so I decided on the M800 for my first build. It took 4 days to get everything soldered and wired together. The offboard wiring gave me a bit of trouble with polarity of the input/output jacks, the DC jack I was using was grounding out the ring to the enclosure and had to be replaced, and I wired the switch wrong the first go. After I found and fixed all those issues, the pedal turned on and the effect worked! It sounded fine, but was more low to medium gain with just a bit of high gain. I suspected something wasn't quite right when I couldn't get Q5 to bias as expected. A post in the troubleshoot forum and a few hours later, the culprit was spotted as the wrong value resistor in the circuit. Replacing that netted a much different animal, but I still wasn't sure it was what I wanted. So, I built another one.

The second try went together much quicker with all the offboard wiring and values correct the first time. The two effects sound the same so I guess this pedal isn't quite what I was looking for, but that's okay.

Other lessons learned:
1) Use multiturn trimpots - biasing the JFETS with single turn trimmers takes a finer touch than what I can provide. I can get them close, but they are extremely touch sensitive when dialing in.
2) When I was testing components, I checked the value against the order sheet and not against the build sheet. This let the wrong value resistor sneak by.
3) I used a soldering tip that was very small for the first build and in order to get enough heat into the board and parts, I had to crank up the temp and hold the tip in place longer than what is typical. I used a larger chisel tip instead of the fine conical tip when I made the second build and it was much easier with a lower temp and less time heating.

All in all, I learned a lot. The second build went together in 3 hours instead of 4 days and worked as expected the first time so even though the pedal(s) are not quite what I was looking for, I still consider this a success.


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## Preverb (Jan 2, 2022)

I am hoping to have mine finished in the next few days (realized I forgot to get 470r resistor and 470p caps).  I didn't know you could get multi-turn trim pots.  Do some people just bias these by ear? I am also looking at getting chisel tip (K tip for T100).  

BTW, what do the tops of these look like?


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## TravisM (Jan 2, 2022)

Preverb said:


> BTW, what do the tops of these look like?


Tops are plain. I've not figured out what to do with them yet.


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## music6000 (Jan 2, 2022)

TravisM said:


> The second try went together much quicker with all the offboard wiring and values correct the first time. The two effects sound the same so I guess this pedal isn't quite what I was looking for, but that's okay.


If it's dialed in right, this is a Marshall in a Box in the higher realm!
Q1, Q2, Q3, Q5 & Q6 should be @ 4.5v, when you get the last one right, go back & re bias again to 4.5v!!!
Q4 is fixed biased
The Trimmer below Q4 is a Tone Trimmer, This can make or break the overall desired sound of this pedal!
Turn it to around 9.00 O'clock ( my Favorite) , just up from the full anti- clockwise position & then try it at 12.00 & 3.00 and you will see what I talking about !!!


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## TravisM (Jan 2, 2022)

music6000 said:


> Q1, Q2, Q3, Q5 & Q6 should be @ 4.5v, when you get the last one right, go back & re bias again to 4.5v!!!
> Q4 is fixed biased



I've got the bias dialed in. Don't get me wrong, they are fire breathing monsters of gain and volume, but I just haven't got tones from them  I like yet. 
I find the bass response in particular gets muddy when the A and low E strings are played at the same time, but single note lead lines are fine.


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## Popnfreshbass (Jan 2, 2022)

You should try the jhs angry charlie clone next. I built the m800 and felt the same as you. I built the angry charlie and it was exactly what the m800 was missing.


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## music6000 (Jan 2, 2022)

TravisM said:


> I've got the bias dialed in. Don't get me wrong, they are fire breathing monsters of gain and volume, but I just haven't got tones from them  I like yet.
> I find the bass response in particular gets muddy when the A and low E strings are played at the same time, but single note lead lines are fine.


Play with the Internal Tone Trimmer & report back!
Bass around 10.00 O'clock is as high as I go.


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## TravisM (Jan 2, 2022)

Popnfreshbass said:


> You should try the jhs angry charlie clone next. I built the m800 and felt the same as you. I built the angry charlie and it was exactly what the m800 was missing.


Thanks, I was strongly considering the dirty Sanchez or brown Betty next, but this gives me something else to think about.


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## music6000 (Jan 2, 2022)

I have a lot of Overdrive & Distortion pedals (200 plus) & JHS would be at the bottom of the list.
I find them sterile, Different Strokes for Different Folks!


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## TravisM (Jan 2, 2022)

music6000 said:


> Play with the Internal Tone Trimmer & report back!
> Bass around 10.00 O'clock is as high as I go.


I think the problem is from dialing it in with a lower output single coil and then hitting it with a humbucker. I tend to grab whatever I have out at the moment and I think I'll be a bit more deliberate with the input source and see what I get.


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## TravisM (Jan 2, 2022)

music6000 said:


> Play with the Internal Tone Trimmer & report back!
> Bass around 10.00 O'clock is as high as I go.


After some very deliberate tuning of the JFET's bias, I was able to tighten the bass response to acceptable levels starting with my highest output humbuckers. Thanks for the additional nudge to get back inside and do this.


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## Travis (Mar 1, 2022)

Anyone know how to make it lower gain ir with more headroom?


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## TravisM (Mar 1, 2022)

Travis said:


> Anyone know how to make it lower gain ir with more headroom?


Put the circuit on a breadboard and try some stuff. When I first assembled it, I accidentally put the wrong resistor in R11 which kept the circuit from going into high distortion. You could start there and see if it does what you want.


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