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

Hello @santiall

1) I don't know if you like to talk about competitors or other brands, but I am wondering what you think about Friedman amps. They kind of took the world of "Marshall"-style amps like no other (known to me). There were always Marshall-clones being made (good and bad), but the BE 100 (and the likes) is the first one, that I really see mentioned EVERYWHERE.

2) You have no limited budget and can buy/use exactly 1 (one) digital amp suite (Softube, Neural, Nembrini, whatever): What is your choice?
 
BahamaDada said:
Hello @santiall

1) I don't know if you like to talk about competitors or other brands, but I am wondering what you think about Friedman amps. They kind of took the world of "Marshall"-style amps like no other (known to me). There were always Marshall-clones being made (good and bad), but the BE 100 (and the likes) is the first one, that I really see mentioned EVERYWHERE.

2) You have no limited budget and can buy/use exactly 1 (one) digital amp suite (Softube, Neural, Nembrini, whatever): What is your choice?
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Hi, there is no such thing as 'competitor', I don't work for Marshall anymore nor have any endorsemnt, ambassador role or any relationship with them apart that I have fully designed or had my input in like 90% of their current catalog :D. People somehow know me for all the years and understandbly associate me with the brand, which I still think it is a great honour, but actually I am working for some of their competitors so I don't have any personal interest in increasing their sales either hahaha

I like the BE100 quite a lot, it is a bit dark, let's call it 'playing-alone friendly' and perhaps trickier to mix in a band situation but an excellent amplifier. I know Dave, we spoke in multiple times, you also can see me with him and Mark in the Tone-Talk youtube channel.
I think there always have been 'the new kid on the block' high gain amp, but the first one clearly going after Marshall cosmetics is him. ANyway, as said, great amps.

Regarding plug-ins/amp suites, you are asking probably the less indicated person in the guitar world... I just don't use them. If I do, it will be some Universal Audio stuff that I run in an Apollo 8 interface for some quick test or reference, but otherwise I have to say that pluging a guitar in a computer interface just kills my inspiration. So on the list above, I have familiarity with the Softube ones (some of the UA are from Softube) but I don't have any opinion or recommendation about the others.
 
santiall said:
you also can see me with him and Mark in the Tone-Talk youtube channel.
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Whoa, I love these kind of in-depth interviews. Thx for the heads up.

Just want to leave this here also:
The JVM OD1 (Orange) to me is the greatest distortion sound of all time (besides the 5150 III 6L6 Blue (2nd channel)). It is tight, but still isn't too tight to be "unmarshally". Does that make sense, at all? On it's own (esp. with V30) it can be quite... "sawy", but this is what will get you through in a mix. Anyway... I just wished they would a) progress to a JVM II or b) continue to build the Satriani JVM bc the "normal" JVM I had I could have lived without reverb, but the NG I'd take any day. And I did not read all of the last pages, but whoever came up with the JVM footswitch shall forever be granted extra curly fries in normal fries and Coca Cola, even when the place only serves Pepsi.
 
2112 said:
Santiago is a certified legend. It was great to have him on the Gear Podcast!

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This is just great, very interesting stuff!

The bit about the Yngwie amp was interesting and also about him using G12T-75s. I never really looked into the YJM100 because I'm not a huge Yngwie fan and it was really expensive when it was released, but the feature set makes a lot of sense for him.

My take on the G12T-75s is that they pretty much only sound great on Marshalls and similar. Maybe Mesa Mark series would do good because I feel they need a mid-forward amp to make them work well.

@santiall I read more about the amp and it seems the power scaling on the YJM is based on the Kevin O'Connor/London Power power scaling method. I used to have a little Stephenson amp that had that and it's still the best power scaling I've tried.

Any reason why this method was not used on more Marshall models or why it is not seen on more amps overall, if the patents have now expired?

For example the Marshall SV20H would be great if it had continuous control over the output volume instead of just a very limited 20/5W toggle where both are going to be too loud for home use.
 
I've been using my multiwatt recto through my JCM800 cab with British T75's in it, and it sounds killer. I'm a big fan of those speakers actually, as well as the V30. Don't really like the Greenback. too vintage sounding for me.
 
BahamaDada said:
Whoa, I love these kind of in-depth interviews. Thx for the heads up.

Just want to leave this here also:
The JVM OD1 (Orange) to me is the greatest distortion sound of all time (besides the 5150 III 6L6 Blue (2nd channel)). It is tight, but still isn't too tight to be "unmarshally". Does that make sense, at all? On it's own (esp. with V30) it can be quite... "sawy", but this is what will get you through in a mix. Anyway... I just wished they would a) progress to a JVM II or b) continue to build the Satriani JVM bc the "normal" JVM I had I could have lived without reverb, but the NG I'd take any day. And I did not read all of the last pages, but whoever came up with the JVM footswitch shall forever be granted extra curly fries in normal fries and Coca Cola, even when the place only serves Pepsi.
Click to expand...
OD1 Orange is probably the 'go-to' mode of that amp and in general the most appreciated although OD1 Red is probably as popular or more.

It is always easy to look backwards and say we should have done this or that, and yes, I do agree that a noise gate would have been a better choice. There was a main issue I guess: back then having a noise gate was a true NO-GO... after we did the Kerry King gate and everybody was impressed then the opinons changed completely.

The footswitch was my idea, it came when studying how to have a footcontroller with many switches that didn't require a complicated connector. Initially I had RJ-45 types (basically the look like a XLR but the connector is like a network cable), then I developed the one wire comms for it. The main goal was that if the cable broke, anyone could replace it easily, not with some fancy multi-pin connector.
 
laxu said:
This is just great, very interesting stuff!

The bit about the Yngwie amp was interesting and also about him using G12T-75s. I never really looked into the YJM100 because I'm not a huge Yngwie fan and it was really expensive when it was released, but the feature set makes a lot of sense for him.

My take on the G12T-75s is that they pretty much only sound great on Marshalls and similar. Maybe Mesa Mark series would do good because I feel they need a mid-forward amp to make them work well.

@santiall I read more about the amp and it seems the power scaling on the YJM is based on the Kevin O'Connor/London Power power scaling method. I used to have a little Stephenson amp that had that and it's still the best power scaling I've tried.

Any reason why this method was not used on more Marshall models or why it is not seen on more amps overall, if the patents have now expired?

For example the Marshall SV20H would be great if it had continuous control over the output volume instead of just a very limited 20/5W toggle where both are going to be too loud for home use.
Click to expand...
Yngwie specifically and very clearly said G12T75 from day one: I want this type of amp with these speakers. Probablt the easiest design brief I ever had :D

The power scaling system was made popular by Kevon O'Connor/London Power. There was a previous patent (long expired) to which he refers all the time, then he experimented and expanded the system, made some books about it, some kits and so on. The YJM and the AFD have a similar implementation as the original patent, the novelty was to include the auto-biasing in all the power settings and I also played a bit with the power amp feedback to compensate some issues with different gains and so on.

The first 20W 'big tube' amplifier that I was experimenting with, and that was used in the initial Origin series had an internal attenuator. That was the whole point, a small amp that could give you power amp distortion at a manageable level. I didn't go the full power-scaling route as it was unnecessarily complicated for a small and simple amp. When I left they changed all that and that idea was never implemented in the studio series either... what do I know :D
 
Hi Santiago, I asked you a few months ago if
The Mercury Magnetics Transformers & choke would make a difference in the 410H
You said no.

I just installed the MM transformers output & power & the MM choke a week ago.
I left 4 year old beat JJ 34’s and mix of old pre amp tubes installed.


IMMEDIATELY.. the clean tone..so much sparkle.
That nasty hiss in red mode?
GONE.
Now, ALL the controls are VERY responsive.
I couldn’t f’n believe it.
The absurd feedback/squeal is HERDS lower
(like a quiet high gain amp)
and unless you DIME the red mode in channels 3&4
-you forgot it was there in the first transformers.
Volume roll back actually works awesome now!!!
Every channel regardless of mode sounds freakin’ dope AF!
It can get juicy or tight & BRUTAL as hell.
The weight that those transformers added
(In blue bell covers) was definitely noticeable,
like bigtime.

Honestly my 1st thought was,
-he said no to protect himself.
 
Life Eats Life said:
Honestly my 1st thought was,
-he said no to protect himself.
Click to expand...
I am not protecting myself, not sure what you mean with that... back in the day we tested different transformers and also over the years many people changed transformers and also reported the same findings.

if it worked for you and you are happy with the result then that's what matters
 
@santiall What do you think about elevating the 6.3vAC heater center tap on DC?
What do you think about modern 12ax7 maximum Cathode-Heater voltage spec and cathode follower stages that typically have 150-180v on the cathode?
 
James Freeman said:
@santiall What do you think about elevating the 6.3vAC heater center tap on DC?
What do you think about modern 12ax7 maximum Cathode-Heater voltage spec and cathode follower stages that typically have 150-180v on the cathode?
Click to expand...
Hi James, I've implemented it, I think, in all the 50W and 100W amps that I have designed. It is quite easy to do and has some advantages regarding noise/hum reduction as well as keeping the tubes in their intended operational ranges.

My to-go way of dealing with heaters tends to be DC for the first or first and second tubes, then DC elevated heaters for the rest. Apart from the 50/60Hz hum that could couple between heater and cathode, the heater AC voltage is usually 'contaminated' by the HT recification pulses and those creates buzz rather than hum. This buzz couples pretty much everywhere, it is specially annoying when coupling in the input stages as this noise will be amplified all over the circuit. THe DC circuit gets rid of that, then the elevated AC does the rest.

You can easily elevate the AC by connecting the center tap of the heater circuit (or one of the AC sides) to on of the HT bleeding cap resistors. You can refer to the AFD100 online schematics. THe JVM and the Peavey 5150 use a divider from the full HT if I am not mistaken.

I am not aware of any particular issues with heater to cathode voltage apart from noise in modern tubes but some are particularly picky with the grid to cathode voltage. When switching the amp on, in a typical direct coupled cathode follower circuit you could be applying full HT to the grid, and 0V to the cathode and that can arch and make a bit of a mess there. I'd suggest to check Merlin Blencowe's book if you haven't checked it yet!
 
Thank you Santiago.
I have visited and referenced the valve wizard site many times over the years, I think I will grab his book.
 
@santiall I have a question regarding your noise gate.
I see that many modern gates are using a THAT 2181 chip (VCA), was that not a common practice before the 2203KK amp?
 
James Freeman said:
@santiall I have a question regarding your noise gate.
I see that many modern gates are using a THAT 2181 chip (VCA), was that not a common practice before the 2203KK amp?
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Not that many tube amps had noise gate by then, just a few as far as I remember. Some were using FETs as an actual on/off gate, Peavey had those diodes in antiparallel and then there were some other solutions with OTAs or VCAs in racks and pedals.
Since the goal was to replace a Rocktron Hush, which used a dedicated VCA and detector implemented in their own chip (SSM2000 by analog devices), it was clear that the way to go was a VCA.
THAT Corp has those ICs that integrate the VCA an an RMS detector so I used one of them. They are pretty much a 2181 with the RMS level detector.
 
SillyOctpuss said:
@santiall how different is the Joe Satriani OD channel from the standard JVM? I know it has less gain but is the circuit very different? Is it possible to mod the standard JVM circuit to JVM JS specs?
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all the channels are different but it is relatively easy to modify the standard JVM to one of the HJS modes. The HJS has extra switching for the different modes so if you modify the standard you'll need to pretty much decide which of the channels and modes you'd want to 'clone'.
It is not easy to convert the standard into the HJS as you'll need to rewrite the firmware and add the extra relays, and so on.

I'd say the the HJS is more mellow, less aggressive. Looser on the lows but still tight to play metal with it.
 
santiall said:
all the channels are different but it is relatively easy to modify the standard JVM to one of the HJS modes. The HJS has extra switching for the different modes so if you modify the standard you'll need to pretty much decide which of the channels and modes you'd want to 'clone'.
It is not easy to convert the standard into the HJS as you'll need to rewrite the firmware and add the extra relays, and so on.

I'd say the the HJS is more mellow, less aggressive. Looser on the lows but still tight to play metal with it.
Click to expand...

Thanks for that @santiall.

I'm very happy with my JVM and just wanted to see if it would be easy to do. if so I thought I'd pick up a second JVM as a project to mod. The HJS is pretty expensive over here now while the standard is cheap and plentiful to pick up used.
 
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