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

Orvillain said:
This is amp heresy!!!!

Depth and presence both at 2 o'clock!!! The amp sounds absolutely MEGA that way!
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sure, those presence and resonance settings will add an extra 'smiley EQ curve' at the power amp. Which pickups/speakers are you using, high output pickups and V30? :p
 
santiall said:
sure, those presence and resonance settings will add an extra 'smiley EQ curve' at the power amp. Which pickups/speakers are you using, high output pickups and V30? :p
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Of course! :rofl

Duncan Distortions in my Les Paul, and V30's in my 4x12 !
 
santiall said:
The JVM was designed with G12T-75 and I tend to use it with those. I also like the Greenbacks and the G12H-75 Creamback. I am not that fan of the V30 though.

For the JCM800 I tend to prefer Greenbacks
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Season 9 Yes GIF by Friends
 
Thanks a lot for this Great Informations Santiago !


Another question:

As i Like the jcm800 a lot. And as i am an electrician..

Are there any JcM800 Kits you Could recommend ?

100/50/20 Watt doesnt matter.

Im very courious how accurate they are
 
Sorxes said:
Thanks a lot for this Great Informations Santiago !


Another question:

As i Like the jcm800 a lot. And as i am an electrician..

Are there any JcM800 Kits you Could recommend ?

100/50/20 Watt doesnt matter.

Im very courious how accurate they are
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I really have no idea, I haven't built nor seen any in person...
I've built myself a couple of clones over the years but I always bought everything myself and had the chassis manufactured for me.

Anyway, as long as the chassis and transformers are half decent, the rest is easiy changed if you fancy any particular brands. The circuits are super simple and have been puiblic for decades so one would hope that they are getting that bit right :grin
 
@santiall

What do you think about 4x12 straight vs angled cabs? What would be your choice and why? For example 1960A vs 1960B?

I might be getting JVM soon and I am trying to gather as much information as possible to make it a good purchase :)

I was originally going to get 1960AHW as I hate plastic handles on other M cabs but... Reading this thread made me think again about 1960A or 1960B to go with the JVM.

I was/am also considering 1960AV. I've had briefly 1960BV (sent it back as the plastic handles were dire and both price/quality/sound was worse or the same as my cheaper Harley Benton 4x12 v30 which I already had) and Mesa 4x12 OS and didn't really like them that much. That made me think that I might prefer angled cabs more after all... even though I was on a hunt at the time to get the most thunderous, punchiest and full sounding cab there was/is. Actually the whole dream rig kind of fell short of my expectation... (Mesa Dual Rectifier + 4x12 Mesa OS straight). Probably user error though ;)

Anyway, I would love to hear your experience, thoughts and every other detail about angled vs straight cabs. Of course any other info is more than welcome as well :)

After reading this thread I am mostly inclined to get 1960A or 1960B at the moment (if I will go with JVM)

I am also thinking about DSL100HR as I really love my DSL1 which is amazing and I love it a lot, except for the *POP* when you change channels from red>green :) . I think I would pair it with 1960AV. Was there any specific speaker that DSL100HR was designed to work with the best?


Also, is it safe to hook up a 100W or even 120W monster of an amp to a single 1x12 speaker (50W or even lower like 25W) if you will not play loud (ohms properly matched of course)?

From a technical point of view, is there anything more to worry about except for playing it too loud?




Thank you in advance for the reply. Health and Happiness to you and to whomever might be reading this/
 
tgchan said:
@santiall

What do you think about 4x12 straight vs angled cabs? What would be your choice and why? For example 1960A vs 1960B?

I might be getting JVM soon and I am trying to gather as much information as possible to make it a good purchase :)

I was originally going to get 1960AHW as I hate plastic handles on other M cabs but... Reading this thread made me think again about 1960A or 1960B to go with the JVM.

I was/am also considering 1960AV. I've had briefly 1960BV (sent it back as the plastic handles were dire and both price/quality/sound was worse or the same as my cheaper Harley Benton 4x12 v30 which I already had) and Mesa 4x12 OS and didn't really like them that much. That made me think that I might prefer angled cabs more after all... even though I was on a hunt at the time to get the most thunderous, punchiest and full sounding cab there was/is. Actually the whole dream rig kind of fell short of my expectation... (Mesa Dual Rectifier + 4x12 Mesa OS straight). Probably user error though ;)

Anyway, I would love to hear your experience, thoughts and every other detail about angled vs straight cabs. Of course any other info is more than welcome as well :)

After reading this thread I am mostly inclined to get 1960A or 1960B at the moment (if I will go with JVM)

I am also thinking about DSL100HR as I really love my DSL1 which is amazing and I love it a lot, except for the *POP* when you change channels from red>green :) . I think I would pair it with 1960AV. Was there any specific speaker that DSL100HR was designed to work with the best?


Also, is it safe to hook up a 100W or even 120W monster of an amp to a single 1x12 speaker (50W or even lower like 25W) if you will not play loud (ohms properly matched of course)?

From a technical point of view, is there anything more to worry about except for playing it too loud?




Thank you in advance for the reply. Health and Happiness to you and to whomever might be reading this/
Click to expand...

Hi!, I personally prefer the B type, I don't really like having speakers pointing to my head... One may say that the B type has a tad more bass than the A ones but, for me, the main factor would be speaker direction. The JVM was designed using a standard 1960B with G12T75 speakers but I know that many people use V30s or Greenbacks, it is a matter of personal choice. If you like the Harley Benton more than the BV then nothing wrong with that, stick to it!
Nowadays I see myself using almost all the time a reactive load an IRs to play guitar, which is another option if you don't need an actual guitar cabinet.

The DSLs, originally, were designed to be paired once again with the 1960A and B cabinets, G12T75. The newer versions are circuit-wise similar to the original amps and were still developed with the standard cabs but nothing wrong to use another cabinet if you prefer.

You can plug a 100W amp into a 1W speaker if you want, it'll be perfectly safe as long as the power that the amp is delivering doesn't exceed 1W for too long... the speaker doesn't know how much the amp 'upstream' could devilver and will do its job regardless of that. Then yes, as you say, if you start getting louder and louder you may end blowing up that speaker and perhaps the amp too... Don't forget that 1W is already quite loud, and 25W isn't too far from 100W when talking about loudness. With this I mean that you would probably be safe but be careful :)

cheers!
 
Hi, I'm new here. I found this forum while researching some information related to the JVM. I think it's amazing to be able to ask direct questions to the brains behind the JVM and more. I wanted to express my gratitude for the opportunity given.

Santiago, I want to thank you for taking the time to stick around and answer all the questions. I went through all 18 pages and I don't think my questions have been asked yet.

I am new to the JVM410H and to Marshalls in general. I used to prefer American-voiced amps, but now I realize I was missing out. Overall, I'm happy with the amp, except for the FX loop.

I'm currently using a single pedalboard for all my amps, and I'm having difficulty with the stock JVM loop. I'm finding it hard to balance the signal and keep it from clipping when using my pedals. I came across a schematic of the loop with a mod for series operation, which I believe came from you. The schematic I found on the Marshall forum suggests tweaking the values a bit. Can you explain how to tweak the loop for the best results? I also noticed that the loop with the series-only mod is very similar to KO TUT1 loop. Would tweaking the values to Kevin's specifications work well? Lastly, if I match it to the 12AT7 return values, what other changes to the reverb mixer triode would I have to make? I assume the Loop Send triode would be better left alone since it's shared with the cathode follower?

I have a question regarding the green/orange/red modes on the JVM. I am trying to understand how this is accomplished. I thought it might be related to changes in the cathode R/C or other amp voicing, but I'm having difficulty pinpointing it on the schematic. Could you please elaborate how this is achieved? Thank you.

When my (your) amp arrived, I decided to check the tube health and the bias. I was surprised to notice that the amp is biased to only 42% of the maximum plate dissipation (481v / 23mA). I'm wondering if this bias setting was a design choice or if it's Marshall's way of managing tube reliability. Most of my high-gain amps are biased on the cold side, but rarely less than 55% of the maximum plate dissipation. What would be your personal recommended range of bias to ensure optimal performance for the JVM410H?

Lastly. I noticed you was kind enough to answer Satch gear questions;

Are there any insights into Joe Satriani's gear list for his 1995 self-titled album? It's my favourite tone of all time and one of my personal top 10 albums. I would love to know the signal chain.

Once again, thank you Santiago. You did a great job on the JVM, and I wish you all the best for the future. For the rest of the forum, thank you for having me.

Edit: schematic of said loop attached
 

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Nerd said:
Hi, I'm new here. I found this forum while researching some information related to the JVM. I think it's amazing to be able to ask direct questions to the brains behind the JVM and more. I wanted to express my gratitude for the opportunity given.

Santiago, I want to thank you for taking the time to stick around and answer all the questions. I went through all 18 pages and I don't think my questions have been asked yet.

I am new to the JVM410H and to Marshalls in general. I used to prefer American-voiced amps, but now I realize I was missing out. Overall, I'm happy with the amp, except for the FX loop.

I'm currently using a single pedalboard for all my amps, and I'm having difficulty with the stock JVM loop. I'm finding it hard to balance the signal and keep it from clipping when using my pedals. I came across a schematic of the loop with a mod for series operation, which I believe came from you. The schematic I found on the Marshall forum suggests tweaking the values a bit. Can you explain how to tweak the loop for the best results? I also noticed that the loop with the series-only mod is very similar to KO TUT1 loop. Would tweaking the values to Kevin's specifications work well? Lastly, if I match it to the 12AT7 return values, what other changes to the reverb mixer triode would I have to make? I assume the Loop Send triode would be better left alone since it's shared with the cathode follower?

I have a question regarding the green/orange/red modes on the JVM. I am trying to understand how this is accomplished. I thought it might be related to changes in the cathode R/C or other amp voicing, but I'm having difficulty pinpointing it on the schematic. Could you please elaborate how this is achieved? Thank you.

When my (your) amp arrived, I decided to check the tube health and the bias. I was surprised to notice that the amp is biased to only 42% of the maximum plate dissipation (481v / 23mA). I'm wondering if this bias setting was a design choice or if it's Marshall's way of managing tube reliability. Most of my high-gain amps are biased on the cold side, but rarely less than 55% of the maximum plate dissipation. What would be your personal recommended range of bias to ensure optimal performance for the JVM410H?

Lastly. I noticed you was kind enough to answer Satch gear questions;

Are there any insights into Joe Satriani's gear list for his 1995 self-titled album? It's my favourite tone of all time and one of my personal top 10 albums. I would love to know the signal chain.

Once again, thank you Santiago. You did a great job on the JVM, and I wish you all the best for the future. For the rest of the forum, thank you for having me.

Edit: schematic of said loop attached
Click to expand...
Hi, thanks for the message and the compliments of course :) . Happy to give a hand whenver I can regarding JVM in particular or any amps or other devices in general.

Would you mind sharing more details about the pedalboard like what pedals, how you use it? (you switch the pedals on.off, switch the loop on/off, etc)..., the series/parallel loop should work set to -10dB, MIX to 100%, then you may need a few dBs of volume compensation from one of the pedals. I wouldn't bother to modify the loop at this stage, at least not after knowing what you have connected there.

Bias, I tend to start at 35mA, perhaps till 40-42mA but usually 35mA does it for me. I forgot what was the initial bias from the factory, probably 30mA?, but they might have changed that over the years. 23mA is definitely cold
 
santiall said:
Hi, thanks for the message and the compliments of course :) . Happy to give a hand whenver I can regarding JVM in particular or any amps or other devices in general.
Click to expand...
Thank you, Santiago. It truly means a lot to me to be able to communicate with you directly. I will definitely have more questions as there are a few things that have been bothering me for a while.

But I'm about to embark on a 7-hour drive to Scotland, so I'm typing this under a bit of time pressure ;)


santiall said:
Would you mind sharing more details about the pedalboard like what pedals, how you use it? (you switch the pedals on.off, switch the loop on/off, etc)..., the series/parallel loop should work set to -10dB, MIX to 100%, then you may need a few dBs of volume compensation from one of the pedals. I wouldn't bother to modify the loop at this stage, at least not after knowing what you have connected there.
Click to expand...
Sure. I have attached the diagram of my rig. The effects loop mainly contains the Eventide H90. The H90 has two insert loops, with the gate and EQ plugged in. I'm just taking advantage of being able to bypass, activate or move these pedals within the effects chain via MIDI without additional MIDI loopers. The Origin Limiter is bypassed when working with the JVM. The H90 is set to "instrument" levels for i/o's


santiall said:
Bias, I tend to start at 35mA, perhaps till 40-42mA but usually 35mA does it for me. I forgot what was the initial bias from the factory, probably 30mA?, but they might have changed that over the years. 23mA is definitely cold
Click to expand...
Thank you, so 65-70% then. Once I return from my holiday, I will adjust the bias and see where the amp feels happier.
 

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Nerd said:
Thank you, Santiago. It truly means a lot to me to be able to communicate with you directly. I will definitely have more questions as there are a few things that have been bothering me for a while.

But I'm about to embark on a 7-hour drive to Scotland, so I'm typing this under a bit of time pressure ;)



Sure. I have attached the diagram of my rig. The effects loop mainly contains the Eventide H90. The H90 has two insert loops, with the gate and EQ plugged in. I'm just taking advantage of being able to bypass, activate or move these pedals within the effects chain via MIDI without additional MIDI loopers. The Origin Limiter is bypassed when working with the JVM. The H90 is set to "instrument" levels for i/o's



Thank you, so 65-70% then. Once I return from my holiday, I will adjust the bias and see where the amp feels happier.
Click to expand...
Hi, let me have a look a the diagram but please bear with me for a couple of days. I was expecting something like "I am using just a Boss DD3 in the loop" :grin

I think I forgot to reply about how the modes are achieved in the JVM. Mostly is switching tubes in an out, then the 3rd gain stage has a variable anode resistor to change its gain. No cathode switching here at all. If my memory isn't wrong I think the signal path was in the handbook specifying which tubes were used in every mode.

Regarding Satriani, again, again please bear with me. Once I have the chance I'll try to get the info from him.

cheers
Santiago
 
santiall said:
Hi, let me have a look a the diagram but please bear with me for a couple of days. I was expecting something like "I am using just a Boss DD3 in the loop" :grin

I think I forgot to reply about how the modes are achieved in the JVM. Mostly is switching tubes in an out, then the 3rd gain stage has a variable anode resistor to change its gain. No cathode switching here at all. If my memory isn't wrong I think the signal path was in the handbook specifying which tubes were used in every mode.

Regarding Satriani, again, again please bear with me. Once I have the chance I'll try to get the info from him.

cheers
Santiago
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Cheers Santiago, take all the time you need. It's essentially one digital unit set to instrument level acting as a host to some other gadgets.

Thank you
 
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