AT LAST ! JVM 410 HJS schematics!!!

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tothemax
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AT LAST ! JVM 410 HJS schematics!!!

Post by tothemax » Wed Sep 11, 2013 10:24 am

emailed *someone* and they sent me these. dang and in color too. [smilie-rock]
hope these help.
Attachments
JVM410HJS Rear Board.pdf
(625.49 KiB) Downloaded 2495 times
JVM410HJS Main Circuit Diagram.pdf
(1.44 MiB) Downloaded 3591 times
JVM410HJS Control Board.pdf
(1.19 MiB) Downloaded 3724 times
amps. EVH 100 watt, rocktron chameleon,fender stage head, marshall mg15r, hiwatt fane loaded 4x12 cab, 2x12 pv cab
guitars. 2011 gibson le paul standard, 2009 crafter elec acoustic.
fx delay/pitchshifter.
sansamp tri ac pedal,
dean markley10s
jim dunlop 60mm picks. spectrflex cables

kocher
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Re: jvm 410 HJS schematics!!!

Post by kocher » Wed Sep 11, 2013 12:03 pm

nice!

Let the modding begin [smilie=banana_smiley.gif]
Amps: JVM410H, Peavey XXX, JCA100H w/depth mod;SLO mod
Cab: Marshall 1960AV
Guitars: Gibson SG Standard 2009, LTD Viper 1000 w/BK Nailbomb;SH-1, some others...
Effects: TC G-Major, G-LAB GSC-1, ISP Decimator, Dunlop CryBaby, Korg Pitchblack Tuner, some more...

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Re: jvm 410 HJS schematics!!!

Post by Tonemeister » Wed Sep 11, 2013 2:51 pm

they do exist?????????? :yikes:
- Marshall JVM410H: Negative Feedback Mod (33k-500k, linear), Compression Mod, One-Wire Cascade Mod, OD2-to-OD1 Mod, P.I. Boost Mod (with 33k in R52), Plexi Cap Mod (1uF), Modified C83 Mod (1- OFF, 2- 0.68uF, 3- 1.0uF, 4- 1.5uF, 5- 2.2uF, 6- 3.2uF), Gain Reduction Mod, Blackface Mod, Mesa Rectifier Mod, 50W (two tubes: 37.5mV), LED Footswitch Mod
- Laney AOR ProTube 3012 Combo: stock
- 2x Marshall 1960B 4xG12T-75
- 2x Dean DIME (FBD, Stealth #29/50), ESP LTD MH-250HT, Fender MIM Strat
- TC Electronic PolyTune, ISP Decimator G-String, Morley Mark Tremonti Power Wah, Ibanez TS9, MXR EVH Phase 90, TC Flashback X4, TC Hall Of Fame

link to my old band "Systatic" (Line6 Vetta II days) http://www.systatic.ca

Casey_Butt
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Re: jvm 410 HJS schematics!!!

Post by Casey_Butt » Wed Sep 11, 2013 4:07 pm

The wife and son are just back from visiting Ukraine for a month, so I probably won't have much time to look at this today, but the first things I notice are...

1) There are some relative minor voicing changes throughout, but it really isn't that much different from the standard JVM.

2) It has many of "our" mods...
- It has the lower compression mods (100k in R75 and R72)
- It has the Plexi cap mod (680nF)
- It has a switchable treble peaker (as with the JCM800-2203 mods)
- It has much less negative feedback than standard - the equivalent of 200k on the standard JVM.
- It has a 220pF cap across each 470pF treble cap in each tone stack (as with the Plexi Channel mods). I first did this to compensate for the JVM having lower value treble and mid pots than a traditional Marshall, which shaves off a little more upper mids... and I thought it was a little known way of addressing this (Santiago, have you been watching [smilie=icon_wink.gif])
- It has the traditional 2203 style gain "stacks", but with larger treble caps (2.2nF)... this is probably inspired by the AFD.

3) The resonance control has been simplified to the simple pot+cap style (which originated as a Fender/Marshall mod... I have this done on my 1959-MkII/2203 clone).

I've only had a few minutes to look at it, but that seems to be the bulk of it. There are other specific gain tweaks along the way, but they are mostly simple resistor value swaps.

I haven't seen the power supply, but I suspect it's similar to our mods... essentially a 2203 spec power supply.
Last edited by Casey_Butt on Wed Sep 11, 2013 8:59 pm, edited 2 times in total.
_ JVM410H: "Blackface" Clean channel, "Plexi" Crunch channel, "Dual Rec" OD2 channel, 3rd stage bias pot with switchable 100nF bypass cap, switchable 470k/470pF "treble peaker", OD1/2 Orange and Red extra gain pot, signal boost into power amp, PI voltage set to 2203 levels, 5H choke w/ 50uF on screens, -ve feedback pot.
_ Marshall 2203/1959 clone - switchable (with FX loop, resonance control and -ve fb pot) built from a Peavey Windsor 'donor' head
_ Fender Deluxe Reverb clone head
_ ADA MP-1, ART Power Plant, Tech 21 PSA-1
_ 1960A cab w/ Celestion G12-65s and G12-75Ts in X-pattern, Peavey JSX cab with Celestion G12M's (UK 6402 cones)
_ Fender Pro 185 (rebuilt) - open back 2x12" with Jensen C12Ks

Surfcaster
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Re: jvm 410 HJS schematics!!!

Post by Surfcaster » Wed Sep 11, 2013 5:23 pm

Suhweeet!!! Can't wait to do some comparisons. If I end up doing any mods based on this, it's most likely only to the OD channel/modes, but I'm still excited...I've been waiting for these to show up! Thanks for posting!! [smilie=gt-happyup.gif]
AMPS
Marshall JVM 205H w/mods - Negative Feedback knob - 3H Mojotone Choke - Mid Shift switch - R72 Compression Mod <> JCM SE head(Home brew, single-ended, EL-34 powered, with JCM800 preamp) <> Prolux 112 (Fender Princeton-based home brew 1x12 combo)
CABS
Home-built 2x12 w/ G12M Greenbacks <> Home-built 1x12 w/WGS Green Beret
GUITARS
2010 G&L USA Legacy HB <> 2015 Gibson Les Paul Less Plus <> 1998 G&L USA Legacy with DiMarzio Area '58 and Area '61 pickups <> 2001 Taylor 414CE

tothemax
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Re: jvm 410 HJS schematics!!!

Post by tothemax » Wed Sep 11, 2013 6:05 pm

i am glad to be able to get these to the group!!!
i was not sure if was going to be able to get them, but i hope they help.
amps. EVH 100 watt, rocktron chameleon,fender stage head, marshall mg15r, hiwatt fane loaded 4x12 cab, 2x12 pv cab
guitars. 2011 gibson le paul standard, 2009 crafter elec acoustic.
fx delay/pitchshifter.
sansamp tri ac pedal,
dean markley10s
jim dunlop 60mm picks. spectrflex cables

S&M Freddy
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Re: jvm 410 HJS schematics!!!

Post by S&M Freddy » Wed Sep 11, 2013 7:41 pm

Nice work TTM! Nice to see all the differences...and similarities revealed.
Cornford RK100
Victory V30
Yamaha THR10
Big box 2x12 cabs with V30's and Celestion G12T-75's, 3x12 Projector cab with classic 80's
Music Man Axis, PRS Mira, Gibson Les Paul Standards ('98 and '00), Gibson Explorer Trad Pro, Gibson Classic DC, Gordon Smith Graduate 60, Graduate Slimline, Explorer, Breadwinner and Gypsy 1.5, Fernandes STJ75, 'Fredster' Telecaster
Nobels midi controller, Cry Baby Wah, Fulltone Deja Vibe, TS 808 clone, TC Dreamscape, TC Flashback, TC HOF, Line 6 M5 Stompbox Modeler in loop, Nobels Pre1 Boost

Surfcaster
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Re: jvm 410 HJS schematics!!!

Post by Surfcaster » Wed Sep 11, 2013 7:52 pm

It's very helpful, totehmax. If nothing else, it helps to satisfy my curiosity.

Casey...just a couple questions:

- concerning the larger 2.2nF treble cap in the gain "stack"...am I correct in thinking this adds highs? When I was converting OD2 to OD1, I lowered that cap from 1.5nF to 1.0nF, and I think I understood I was lowering the highs a bit. If that is what it's doing, that's one I can cross of my list already...don't think I'd want to add any highs!

- and concerning the 220pF cap across the 470pF treble cap in the tone stack...do I understand you correctly that this will thicken up the upper mids? I also see there is a 47K resistor added in series with the tone pot. What does this do and is it necessary if you add the 220pF cap?

- by the gain stacks on the OD and Crunch channels, there is a 470K resistor in series with a 470pF cap across the two legs of the gain pot that are not on the stock JVM...what do these do?

I was also interested to see how they achieve their "Mid Shift" for the OD channels. It looks like they have two 47nF caps in series on the mid tone control, switching the one in and out. When the second is switched in, you get total capacitance of 23.5nF, very close to the typcial 22nF, otherwise you get 47nF. And when I ran thevalues in the Duncan Tone Stack calculator, 47nF with a 33K slope resistor produces a curve quite close to using a 47K slope resistor with a 22nF cap! Of course, the Duncan calculator does not take the caps by the gain pot into account, so it's not giving the whole picture, but it's probably a big part of the picture.
AMPS
Marshall JVM 205H w/mods - Negative Feedback knob - 3H Mojotone Choke - Mid Shift switch - R72 Compression Mod <> JCM SE head(Home brew, single-ended, EL-34 powered, with JCM800 preamp) <> Prolux 112 (Fender Princeton-based home brew 1x12 combo)
CABS
Home-built 2x12 w/ G12M Greenbacks <> Home-built 1x12 w/WGS Green Beret
GUITARS
2010 G&L USA Legacy HB <> 2015 Gibson Les Paul Less Plus <> 1998 G&L USA Legacy with DiMarzio Area '58 and Area '61 pickups <> 2001 Taylor 414CE

RockmanCentral
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Re: jvm 410 HJS schematics!!!

Post by RockmanCentral » Wed Sep 11, 2013 8:41 pm

Hi, I'm a new member here (sorry, I'll get to the introduction page soon, promise!!).

OK, I think I figured out the Noise Gate circuit.
Looks like it's the (trigger?) section right under the input stage, with VGate going to IC105, and the Gate control Pots going from CN36N~Q on the control board to IC105 via CN27N~Q.
And perhaps the section next to it, below V102A/B, is the actual gate that does the muting of the signal prior to the FX Loop?

BTW, it looks like removing the Reverb left V101B as an UNUSED tube stage!
Wonder if someone will come up with a use for it?

Thanks in advance to everyone's help!!
Last edited by RockmanCentral on Wed Sep 11, 2013 11:07 pm, edited 2 times in total.
Gear:
Marshall JVM 410HJS - -ve Feedback
Kemper Profiling Rack
Two Notes Torpedo Live
Marshall 1960 HW Stack - G12H-30's
Marshall 1960 Lead Stack - G12T-75's
Rockman Stack with Rev 20 Sustainor
Rockman XP212, XP100a
Echoplex EP3 - Hyperspace Pedal
Gibson Collectors Choice #10 Tom Scholz 68 Les Paul Goldtop
PRS SE 24 Custom Floyd - Sustainiac, DiMarzio Super Distortion, Graph Tech LB63 Floyd Rose, Acoustiphonic preamp
Jackson Dinky Reverse - Sustainiac, DiMarzio Super Distortion
Epiphone 68 Reissue Les Paul Goldtop

Boston Covers:
http://www.youtube.com/user/RockmanCentralBob

Casey_Butt
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Re: jvm 410 HJS schematics!!!

Post by Casey_Butt » Wed Sep 11, 2013 9:16 pm

Surfcaster wrote:It's very helpful, totehmax. If nothing else, it helps to satisfy my curiosity.

Casey...just a couple questions:

- concerning the larger 2.2nF treble cap in the gain "stack"...am I correct in thinking this adds highs? When I was converting OD2 to OD1, I lowered that cap from 1.5nF to 1.0nF, and I think I understood I was lowering the highs a bit. If that is what it's doing, that's one I can cross of my list already...don't think I'd want to add any highs!
It adds high mids. When you lower that cap you raise the point at which the high-mid/high frequencies start bypassing the resistor right in front of the gain pot. By making that cap larger you're allowing more high-mids to bypass the resistor and that turns into a "high-mids peaker". It's part of the reason some amps (the AFD100 for example) have almost a nasally quality to them.
- and concerning the 220pF cap across the 470pF treble cap in the tone stack...do I understand you correctly that this will thicken up the upper mids? I also see there is a 47K resistor added in series with the tone pot. What does this do and is it necessary if you add the 220pF cap?
The 220pF cap is there to let more upper mids through. Either Satch voiced that desire to Santiago and that's how he went about getting it, or it was done to make the JVM's tone stack pass roughly the same frequencies as the older stacks with 250k treble and 25k mids pots. The standard JVM has 200k treble pots and 20k mid pots - even though that's close to the old 250k/25k pots, it does result in some upper mids being shaved off. This is an easy way to let them back.

The 47k was probably put there to control the overall brightness of the amp. The 410JS has differences that make it brighter than the standard JVM, so Santiago probably controlled that by putting the 47k before the treble pot. In comparison, that would be like a 1959 or 2203 with the treble pot that only goes to 8.1 instead of all the way to 10. The standard JVM doesn't need that because it doesn't shave off as much bass in places and therefore isn't as bright overall.
- by the gain stacks on the OD and Crunch channels, there is a 470K resistor in series with a 470pF cap across the two legs of the gain pot that are not on the stock JVM...what do these do?
It limits the effect of the bright cap as you turn the gain knob. On a traditional Marshall (and Fender, from which it was "inspired") the bright cap allows treble frequencies to bypass the gain pot. So as you turn the gain down only the mids and bass gets shaved off (and therefore the amp seems to get brighter). Putting the 470k there in series with the 470pF bright cap means that the amp won't get that much brighter as the gain is turned down (or darker as the gain is turned up, however you want to look at it). This was probably done to tweak the top end but I also suspect Satch didn't want the tone to change as much with gain level and this is how Santiago addressed it.
I was also interested to see how they achieve their "Mid Shift" for the OD channels. It looks like they have two 47nF caps in series on the mid tone control, switching the one in and out. When the second is switched in, you get total capacitance of 23.5nF, very close to the typcial 22nF, otherwise you get 47nF. And when I ran thevalues in the Duncan Tone Stack calculator, 47nF with a 33K slope resistor produces a curve quite close to using a 47K slope resistor with a 22nF cap! Of course, the Duncan calculator does not take the caps by the gain pot into account, so it's not giving the whole picture, but it's probably a big part of the picture.
I think you're right. Satch probably wanted the 47k/22nF style stack to give him a little more scooped rhythm sound when he wanted it. There's a lot of mids tweaking going on in that amp - not surprisingly, I guess, since Satch is very much an '80s style lead virtuoso. It looks like he "specified" a lot of his desired modifications around the mids and getting the lead tone the way he liked.
_ JVM410H: "Blackface" Clean channel, "Plexi" Crunch channel, "Dual Rec" OD2 channel, 3rd stage bias pot with switchable 100nF bypass cap, switchable 470k/470pF "treble peaker", OD1/2 Orange and Red extra gain pot, signal boost into power amp, PI voltage set to 2203 levels, 5H choke w/ 50uF on screens, -ve feedback pot.
_ Marshall 2203/1959 clone - switchable (with FX loop, resonance control and -ve fb pot) built from a Peavey Windsor 'donor' head
_ Fender Deluxe Reverb clone head
_ ADA MP-1, ART Power Plant, Tech 21 PSA-1
_ 1960A cab w/ Celestion G12-65s and G12-75Ts in X-pattern, Peavey JSX cab with Celestion G12M's (UK 6402 cones)
_ Fender Pro 185 (rebuilt) - open back 2x12" with Jensen C12Ks

tothemax
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Re: jvm 410 HJS schematics!!!

Post by tothemax » Wed Sep 11, 2013 9:41 pm

no problem gang.
i was curious myself. i love my jvm 410 with the little mods she the best i ever owned.

just finished the choke mod. put in a mercury mag. EXCELLENT!!! [smilie=banana_smiley.gif]

it confuses me why no hjs owner would post these???

maybe you can mod the jvm to jvmhjs specs but not the other way around?? smilie=icon_lol.gif
amps. EVH 100 watt, rocktron chameleon,fender stage head, marshall mg15r, hiwatt fane loaded 4x12 cab, 2x12 pv cab
guitars. 2011 gibson le paul standard, 2009 crafter elec acoustic.
fx delay/pitchshifter.
sansamp tri ac pedal,
dean markley10s
jim dunlop 60mm picks. spectrflex cables

Surfcaster
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Re: jvm 410 HJS schematics!!!

Post by Surfcaster » Wed Sep 11, 2013 10:18 pm

Interesting, Casey. Thanks for the explanation.

One other question...can anybody locate the choke on the schematics? I can see where it connects, but haven't been able to find the choke itself...just curious as to what value it is?
AMPS
Marshall JVM 205H w/mods - Negative Feedback knob - 3H Mojotone Choke - Mid Shift switch - R72 Compression Mod <> JCM SE head(Home brew, single-ended, EL-34 powered, with JCM800 preamp) <> Prolux 112 (Fender Princeton-based home brew 1x12 combo)
CABS
Home-built 2x12 w/ G12M Greenbacks <> Home-built 1x12 w/WGS Green Beret
GUITARS
2010 G&L USA Legacy HB <> 2015 Gibson Les Paul Less Plus <> 1998 G&L USA Legacy with DiMarzio Area '58 and Area '61 pickups <> 2001 Taylor 414CE

Casey_Butt
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Re: jvm 410 HJS schematics!!!

Post by Casey_Butt » Wed Sep 11, 2013 10:41 pm

Surfcaster wrote:Interesting, Casey. Thanks for the explanation.

One other question...can anybody locate the choke on the schematics? I can see where it connects, but haven't been able to find the choke itself...just curious as to what value it is?
Given those 100uF main and screen caps it's almost assuredly 3-5H... just as the 2203s and 1959s.
_ JVM410H: "Blackface" Clean channel, "Plexi" Crunch channel, "Dual Rec" OD2 channel, 3rd stage bias pot with switchable 100nF bypass cap, switchable 470k/470pF "treble peaker", OD1/2 Orange and Red extra gain pot, signal boost into power amp, PI voltage set to 2203 levels, 5H choke w/ 50uF on screens, -ve feedback pot.
_ Marshall 2203/1959 clone - switchable (with FX loop, resonance control and -ve fb pot) built from a Peavey Windsor 'donor' head
_ Fender Deluxe Reverb clone head
_ ADA MP-1, ART Power Plant, Tech 21 PSA-1
_ 1960A cab w/ Celestion G12-65s and G12-75Ts in X-pattern, Peavey JSX cab with Celestion G12M's (UK 6402 cones)
_ Fender Pro 185 (rebuilt) - open back 2x12" with Jensen C12Ks

jensbrix
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Re: jvm 410 HJS schematics!!!

Post by jensbrix » Thu Sep 12, 2013 7:15 am

Anyone looked into the gate section? Is it realistic to do anything like that on a standard JVM ?
Guitars
Gibson Les Paul Standard
ESP Horizon

Amps
Marshall JVM 410H
Marshall JCM 900 2500 SL-X (modded)
Marshall JCM 900 1960A+B with Greenbacks x T75

Surfcaster
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Re: jvm 410 HJS schematics!!!

Post by Surfcaster » Thu Sep 12, 2013 2:29 pm

RockmanCentral wrote:Hi, I'm a new member here (sorry, I'll get to the introduction page soon, promise!!).

OK, I think I figured out the Noise Gate circuit.
Looks like it's the (trigger?) section right under the input stage, with VGate going to IC105, and the Gate control Pots going from CN36N~Q on the control board to IC105 via CN27N~Q.
And perhaps the section next to it, below V102A/B, is the actual gate that does the muting of the signal prior to the FX Loop?

BTW, it looks like removing the Reverb left V101B as an UNUSED tube stage!
Wonder if someone will come up with a use for it?

Thanks in advance to everyone's help!!
It's really tough to see how the connectors match up on these schematics! I thought it was tough on the original JVM schematics, but there was a rhyme and reason that I could figure out there. I haven't been able on these yet. Maybe someone else can help??
AMPS
Marshall JVM 205H w/mods - Negative Feedback knob - 3H Mojotone Choke - Mid Shift switch - R72 Compression Mod <> JCM SE head(Home brew, single-ended, EL-34 powered, with JCM800 preamp) <> Prolux 112 (Fender Princeton-based home brew 1x12 combo)
CABS
Home-built 2x12 w/ G12M Greenbacks <> Home-built 1x12 w/WGS Green Beret
GUITARS
2010 G&L USA Legacy HB <> 2015 Gibson Les Paul Less Plus <> 1998 G&L USA Legacy with DiMarzio Area '58 and Area '61 pickups <> 2001 Taylor 414CE

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