great stuff! Thanks for going through the mods and explaining the influence of each section. Sounds really cool, a great chewy character to the distortion and nicely balanced low end coming from the depth mod! Would you rate these as a donor amp for any of your PCB's? They regularly go really cheap over here
If I change the preamp(gain) pots (normal and overdrive) to 500k would it be too bright? I have done these exact mods to my JCA 100 and am just waiting on new tubes to fire her up.
JASE PLEASE DO A BILL OF MATERIAL AND INSTRUCTIONS TO DO THIS MOD!!! I HAVE A JCA22H THAT IM MODDING RIGHT NOW, AND HAVE MODS FROM EPIC TONE, BUT THEIR INSTRUCTIONS ARE DOGGY DOO. YOU ARE MY FAV MODDER AND FAV AUSSIE LOL!!! IM A MIDWESTERN AMERICAN BUT HAVE TRUE AUSSIE AND KIWI FAMILY DUE TO MY GRANDFATHER WHO WAS A MARINE IN THE PACIFIC IN WW2 AND WELL..... LETS JUST SAY WE HAD A WHOLE OTHET SIDE OF OUR FAMILY WE DIDNT KNOW ABOUT BUT NOW WE DO. AND I LOVE YOU GUYS AUSSIES AND KIWIS YOURE ALL ABSOLUTE RIOTS😂😂😂. LOVE YA BROTHER!
I see that the R36 1M resistor was replaced with a 470K resistor. I'm a little curious about this. Is it to correct the symmetry because you replaced the plate cap with a 220K? It seems like increasing the plate resistor would be adding gain to an already high gain amp, so I'm assuming the reduction of R36 attenuates it. I'm trying to gain a better understanding of amp design, and certainly appreciate your tutorials.
@@HeadfirstAmps Thank you for the reply! I'm currently working on a project based on a similar design, but I want to keep some of the unforgiving character in. My initial impression was similar to yours. (that the highs were harsh, and that the bass was flagellating). Traditionally, Marshall's had some bass flub. Some people like it for palm mutting. I'm considering going about half way with your design to see how I like it. I took out all of the caps, and replaced them with a mix of Orange drop polyester, and Polypropylene caps thinking that they might help a bit. I also went with your suggestion of using silver mica caps to replace the ceramics. I'm also adding a Hammond 156G choke, and going with bigger transformers, and Russian 6P14P power tubes. The tubes are supposed to sound more like 6V6's. I'm now waiting on parts. Do you accept donations for technical advice? I have another amp I'm working on.
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Sounds great buddy, I would love to see a step by step video guide. Keep up the great work.
I'd love to see this mod in more detail as I do have one of these and this sounds immense!
Thanks, Man. I've got a JCA 22H and a 2212 combo that I think I'll try some of these on.
That Jet City amp is ready for take off!!!
Ha ha, brilliant.
Sounds great man
Thanks for sharing!
great stuff! Thanks for going through the mods and explaining the influence of each section. Sounds really cool, a great chewy character to the distortion and nicely balanced low end coming from the depth mod!
Would you rate these as a donor amp for any of your PCB's? They regularly go really cheap over here
Very good mod. One for the JCA22H ?? Thanks.
If I change the preamp(gain) pots (normal and overdrive) to 500k would it be too bright? I have done these exact mods to my JCA 100 and am just waiting on new tubes to fire her up.
Sure want that diy guide!
that sounds great!!! i wish mine sounded similar. Could you please go on and make the detailed video on how to achieve these mods?
Great stuff bro!
Digging the sounds and would like a more detailed breakdown of this mod but curious if this mod would work with the 100 watt version?
It sure will, same preamp circuit.
Your videos are awesome! I loved your Tone Talk episode as well. Is there a straightforward mod to perform to the crunch channel to make it cleaner?
Hey thanks. Which model JC do you have? I’ll look it up.
@@HeadfirstAmps the JCA50H.
JASE PLEASE DO A BILL OF MATERIAL AND INSTRUCTIONS TO DO THIS MOD!!! I HAVE A JCA22H THAT IM MODDING RIGHT NOW, AND HAVE MODS FROM EPIC TONE, BUT THEIR INSTRUCTIONS ARE DOGGY DOO. YOU ARE MY FAV MODDER AND FAV AUSSIE LOL!!! IM A MIDWESTERN AMERICAN BUT HAVE TRUE AUSSIE AND KIWI FAMILY DUE TO MY GRANDFATHER WHO WAS A MARINE IN THE PACIFIC IN WW2 AND WELL..... LETS JUST SAY WE HAD A WHOLE OTHET SIDE OF OUR FAMILY WE DIDNT KNOW ABOUT BUT NOW WE DO. AND I LOVE YOU GUYS AUSSIES AND KIWIS YOURE ALL ABSOLUTE RIOTS😂😂😂. LOVE YA BROTHER!
Fantastic Job Jason , i ve wrote you privately , but i did not get any answer back , about metro loop full caps completed prices and a private info
Sorry I missed your email. Can you please resend direct to headfirst.amplification@gmail.com
@@HeadfirstAmps pm sent
I see that the R36 1M resistor was replaced with a 470K resistor. I'm a little curious about this. Is it to correct the symmetry because you replaced the plate cap with a 220K? It seems like increasing the plate resistor would be adding gain to an already high gain amp, so I'm assuming the reduction of R36 attenuates it.
I'm trying to gain a better understanding of amp design, and certainly appreciate your tutorials.
Dropping the value of that resistor to ground will help to pull some bottom end out the signal, like a high pass filter.
@@HeadfirstAmps Thank you for the reply! I'm currently working on a project based on a similar design, but I want to keep some of the unforgiving character in. My initial impression was similar to yours. (that the highs were harsh, and that the bass was flagellating). Traditionally, Marshall's had some bass flub. Some people like it for palm mutting. I'm considering going about half way with your design to see how I like it.
I took out all of the caps, and replaced them with a mix of Orange drop polyester, and Polypropylene caps thinking that they might help a bit. I also went with your suggestion of using silver mica caps to replace the ceramics. I'm also adding a Hammond 156G choke, and going with bigger transformers, and Russian 6P14P power tubes. The tubes are supposed to sound more like 6V6's. I'm now waiting on parts.
Do you accept donations for technical advice? I have another amp I'm working on.
I just did this mod step by step and now my Overdrive pot does not work. any ideas???
Please post questions over in the FB DIY group if possible
@@HeadfirstAmps done. Thank you
Can we use that schematic for jca 100/100hdm?
Yes. It has the same preamp circuit.
Shouldn't R32 be 2.2M ohms?
so you sell a slo50 pcb?
No. Check out Alex @ Sirrius Amplification, he will be able to help.