Santiago Alvarez (electronics engineer, JVM, YJM, AFD...)

2dor said:
@santiall I recall Bjon of In Flames going Marshall way back in the late 2000s (think he started using JVMs) and then recently saw a sit-down with Ola where he mentioned there was a prototype for the amp:



Would love to know more about how that amp differed from the main production line stuff :D
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Björn was one of the first JVM endorsers back in the day. They used JVMs for some time
That other amp was a prototype of a metal amp that another engineer, Jonathan Langstaff, worked on. It roughly was the orange OD1 mode of a JVM with a tube screamer boost and the 2203KK gate. Nothing to do with Cameron or other Jose style amps.
People like Bonamassa tried that amp and enjoyed it a lot. I'm not sure why it never ended seeing the light, I remember some people wanting to market or as a metal head, others as a more generic amp... ended here:
https://reverb.com/item/6897268-marshall-doug-aldrich-dla-custom-prototype-1-of-2-2009
 
santiall said:
Björn was one of the first JVM endorsers back in the day. They used JVMs for some time
That other amp was a prototype of a metal amp that another engineer, Jonathan Langstaff, worked on. It roughly was the orange OD1 mode of a JVM with a tube screamer boost and the 2203KK gate. Nothing to do with Cameron or other Jose style amps.
People like Bonamassa tried that amp and enjoyed it a lot. I'm not sure why it never ended seeing the light, I remember some people wanting to market or as a metal head, others as a more generic amp... ended here:
https://reverb.com/item/6897268-marshall-doug-aldrich-dla-custom-prototype-1-of-2-2009
Click to expand...
Appreciate your taking the time to reply & share some knowledge on this.
Thank you!
 
@santiall I recall you saying that there is a small error in the Jubilee schematic found online compared to the original '87 and the reissue, do you mind sharing what it is?
 
James Freeman said:
@santiall I recall you saying that there is a small error in the Jubilee schematic found online compared to the original '87 and the reissue, do you mind sharing what it is?
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Hi, copy paste of what we spoke before: few people asked about that 'mistake' in the Jubilee schematic, it was an old online schematic that had a value corrected by hand and that value was wrong. I was trying to find it in my notes but it was many years ago and I also don't have any of the documents I was using while in Marshall. The schematics that I see now online seem to be OK.
I vaguely remember that it was on of the 100n caps, maybe around the bass control or the feedback that was marked as 470n.
 
Santiago, are the heaters on the reissue Silver Junilee 2555x DC or AC?
Can't see much from internet photos of the board, it's black, also, is the PCB multi-layered or just top bottom?
 
@santiall Good evening! I recently picked up a used Marshall DSL100H that I believe was manufactured in 2016. Would you know what the bias recommendation is on this amp? I'm finding all kinds of info online, but none that look reliable. One YT video was recommending 90mV and I emailed Marshall, but have not heard back yet. Thanks!!
 
Byrdman said:
@santiall Good evening! I recently picked up a used Marshall DSL100H that I believe was manufactured in 2016. Would you know what the bias recommendation is on this amp? I'm finding all kinds of info online, but none that look reliable. One YT video was recommending 90mV and I emailed Marshall, but have not heard back yet. Thanks!!
Click to expand...
Hi, I think the 45mA/tube value was the recommendation for the very first JCM2000 amps made in UK.
Not sure what they recommend for the newer versions but I'd imagine something more 'normal' in the range of 35-40mA/tube.
 
santiall said:
Björn was one of the first JVM endorsers back in the day. They used JVMs for some time
That other amp was a prototype of a metal amp that another engineer, Jonathan Langstaff, worked on. It roughly was the orange OD1 mode of a JVM with a tube screamer boost and the 2203KK gate. Nothing to do with Cameron or other Jose style amps.
People like Bonamassa tried that amp and enjoyed it a lot. I'm not sure why it never ended seeing the light, I remember some people wanting to market or as a metal head, others as a more generic amp... ended here:
https://reverb.com/item/6897268-marshall-doug-aldrich-dla-custom-prototype-1-of-2-2009
Click to expand...
Build me one dude!!!
Fire in the hole with that bad boy!!!
 
santiall said:
Hi, I think the 45mA/tube value was the recommendation for the very first JCM2000 amps made in UK.
Not sure what they recommend for the newer versions but I'd imagine something more 'normal' in the range of 35-40mA/tube.
Click to expand...
Thank you! I appreciate you getting back with me quickly and being here to help us all. Have a great day!
 
santiall said:
Hi, I think the 45mA/tube value was the recommendation for the very first JCM2000 amps made in UK.
Not sure what they recommend for the newer versions but I'd imagine something more 'normal' in the range of 35-40mA/tube.
Click to expand...
If I remember correctly the info I found back when I had a JCM2000 DLS50 was to bias it to 35 mA per tube. No idea how official that was. Not that it stayed there for long thanks to the damn bias drift on those amps...
 
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