VH style Mods

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mightymike
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VH style Mods

Post by mightymike » Thu Mar 31, 2011 11:58 am

With so many VH mods scattered throughout this forum, it's hard to know where to start. Especially with some of these threads over 100 pages long. The purpose of this Sticky Thread is to list these mods, and link to these threads and other sources, but pull the most important info (Pics, Layouts, schematics, parts, and how to info) to the front so it's at your fingertips here. The point won't be to discuss anything here, because the meat and potatoes of the subject will be lost in the 100 pages of replies, thus defeating the purpose. If you want to see the discussion, the link to the related thread (If applicable) will be listed in this summary for quick access.

I think a thread like this is long overdue, and I hope it really helps builders find what they are looking for.
Your help is more than welcome . It's encouraged
Just PM me if you have something cool to add.

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Re: VH style Mods

Post by mightymike » Thu Mar 31, 2011 3:10 pm

Jose Master Volume Thread
http://forum.metroamp.com/viewtopic.php ... ter+volume
As you will read in the above thread, the Jose MV doesn't work as well in 12000/1959 models.
jose mod edited with zenor diode.jpg
jose mod edited with zenor diode.jpg (26.98 KiB) Viewed 38384 times

So if you try this... (Even on it's own it cool)

Consider cascading your gain stages by Changing Plate and/or Cathode Resistors
as explained well here. http://forum.metroamp.com/viewtopic.php ... 52#p271506
Except by flemingmras » Wed Sep 23, 2009 5:47 pm
Just so you understand how things work in a preamp...

Dropping the value of the cathode resistor (i.e. the resistor connected to pin 3 or the ones connected to 6 and 8 on V1) increases gain. You can also increase gain by raising the value of the plate resistor (i.e. the resistor connected to pin 1).

If you have issues with high frequency oscillation, there are a couple of ways of taming that. You can place a 47pF or some other low value cap across pins 1 and 3 (or 6 and 8 depending on which side of the tube it's coming from) on the stage that you're adding gain to. Placing this cap across the plate resistor should do the same thing. Because it's such a low value, it shouldn't have any noticeable affect on your highs.

On the Super Lead circuit, V1's gain stages are mixed together via the mixer resistors (470K...or 270K, depending on which era circuit you have). Instead of mixing them, you can cascade them for more gain.
I prefer small changes in resistance so that the character of the tone remains Marshall.

Some like the LarMar Master Volume even better
$10 at Metro http://metroamp.com/store/index.php?mai ... cts_id=498
More info here: http://metroamp.com/wiki/index.php/Lar/Mar_PPI-MV

Then there's the Cerre m mod if you brave enough to try it. The gain is sick..
http://www.twistyneck.net/cm.html
http://www.youtube.com/watch?v=gy2YTufL ... re=related
http://www.youtube.com/watch?v=I7HAknji ... er&list=UL
If I ever tried this I would put some protection circuits, more heat sinking, and wire this internally. (not with drill bits lol)
Twistyneck has a thread here too. http://forum.metroamp.com/viewtopic.php ... Twistyneck
I think Larry had the protection circuit idea where a fuse protects your trannys

10K in a MV Jose Circuit
http://forum.metroamp.com/viewtopic.php ... se#p292671

Clip Jose MV + One wire mod in 1971 Super Lead...
http://forum.metroamp.com/viewtopic.php ... se#p288019" onclick="window.open(this.href);return false;

Mod 5 or M5
Specs: Marshall 2203/2204, with 12000 spec low filtering, with a LAr/Mar PPIMV added, the 220k resistor after the pre-PI MV, and only a couple of other component changes like a 100pF cap instead of a 470-500pF cap at the 470K/470K voltage divider, a 25µF/25V across the 820 ohms cathode R of V2a, and .1 coupling caps instead of .022's after the PI plates.

Pics
http://www.mediafire.com/imageview.php? ... 15&thumb=6
http://www.mediafire.com/imageview.php? ... 09&thumb=6
http://www.mediafire.com/imageview.php? ... tb&thumb=6
http://www.mediafire.com/imageview.php? ... l6&thumb=6
http://www.mediafire.com/imageview.php? ... i8&thumb=6
http://www.mediafire.com/imageview.php? ... h7&thumb=6
Schematic by Larry from the above pics
Marshall_Rockstah_Mod_5.pdf
(24.1 KiB) Downloaded 6931 times

If you have a typical 12000 tone board that looks like this:
http://forum.metroamp.com/download/file.php?id=4851 ...And you want to convert it to be like the schematic and Pics above

Start by doing this:
1)Remove V1a Cathode Capacitor, and V1a Cathode Resistor - Replace with a 10k Resistor
2)Remove Bright CH Mix Cap (also known as a High Pass Treble Peaking Cap), replace with 100pf Silver Mica Cap
3)Remove .022uf Phase Inverter Coupling caps (also known as Output coupling caps), and replace with .1uf caps
4)Remove V1B Plate Bypass Cap, and replace with an Xicon .022uf
5)Remove V2A Cathode Capacitor, and replace with a Sprague 25uf little black electrolytic cap
6)You could probably stick with the big blue preamp cap value in the middle of the board if you're in that range, but this particular amp has a 33uf/33uf Black F&T Axial. (2 wires out one end/one out the other like George used to sell)

Then install a 220k resistor from pin 2 (middle pin) of the Treble pot, to pin 1 of the Master Volume
Change the wiring on your two Volume pots , and v1 to match a 2203

Install a Lar Mar PPIMV
-------------------------------------------
Then check that you have pretty much stock 12000 filtering.
2- 32uf Axials on the Screens
2- 100uf Mains, or 2- Double Jumped 50/50uf
V3 Cap in the Corner is either a single TAD 32uf, a dual 16uf, or a 32uf/32uf trying to remember. Try em all.

Note: When done...don't stop..You should tweak to taste. Build a v2a tree with 4 or 5 caps ranging from .68uf to 330uf, and try each one by one with a jumper.. till you find your favorite. Trust your ears. Don't just settle on .1uf in the output couplers, try .02 as well, or .047. It might sound better for your setup.These affect your sound a lot. Also try different tone stacks, and mixer caps. (I made a clip on tone stack changer) Try even a different resister than the 220k. Try a 100k if that sounds better. You might have different speaker, pickup, or guitar body wood, than a Early 90's RI Greenback, Current Production Stock Dimarzio Super Distortion, with a Northern Ash Frankie Body from Dive Bomb with the 500k Pot/ With no Cap.


Here's a different amp
More pics of a 1959Mod5
This one has typical values on v2a, Mixer Cap, and no 220k off the Master Volume.

http://www.mediafire.com/imageview.php? ... bc&thumb=6
http://www.mediafire.com/imageview.php? ... rn&thumb=6
http://www.mediafire.com/imageview.php? ... f9&thumb=6
http://www.mediafire.com/imageview.php? ... ij&thumb=6
http://www.mediafire.com/imageview.php? ... 10&thumb=6
http://www.mediafire.com/imageview.php? ... mk&thumb=6
http://www.mediafire.com/imageview.php? ... ac&thumb=6
http://www.mediafire.com/imageview.php? ... ew&thumb=6
http://www.mediafire.com/imageview.php? ... h6&thumb=6
http://www.mediafire.com/imageview.php? ... 32&thumb=6
http://www.mediafire.com/imageview.php? ... 5b&thumb=6
http://www.mediafire.com/imageview.php? ... ch&thumb=6
http://www.mediafire.com/imageview.php? ... 0u&thumb=6
http://www.mediafire.com/imageview.php? ... sc&thumb=6
http://www.mediafire.com/imageview.php? ... gp&thumb=6
http://www.mediafire.com/imageview.php? ... 90&thumb=6
http://www.mediafire.com/imageview.php? ... iq&thumb=6
http://www.mediafire.com/imageview.php? ... ki&thumb=6
http://www.mediafire.com/imageview.php? ... ha&thumb=6
http://www.mediafire.com/imageview.php? ... ae&thumb=6
http://www.mediafire.com/imageview.php? ... cj&thumb=6
http://www.mediafire.com/imageview.php? ... 93&thumb=6
http://www.mediafire.com/imageview.php? ... gk&thumb=5
http://www.mediafire.com/imageview.php? ... zd&thumb=6
http://www.mediafire.com/imageview.php? ... z3&thumb=6
http://www.mediafire.com/imageview.php? ... 64&thumb=6
http://www.mediafire.com/imageview.php? ... e4&thumb=6
http://www.mediafire.com/imageview.php? ... hr&thumb=6
http://www.mediafire.com/imageview.php? ... le&thumb=6
http://www.mediafire.com/imageview.php? ... 9j&thumb=6

Here's another Mod 5 Schematic. It has a couple mistakes. This one doesn't have the 220k resistor, or 100pf across the voltage dividers aka mix resistors. It just has a .68uf on v2a, and way higher filtering.
mod5.png
100k/1M in the PI should be 1,1M and 1M
and the 470k before the gain pot is bypassed but I don't know the value
(85.66 KiB) Not downloaded yet
It came from this thread.. http://forum.metroamp.com/viewtopic.php ... 9&p=340333


1.2khz boost mod for the MXR EQ from Good Guest. It really nails I'm the One tone.
From Good Guest: OK Some interesting things about the mxr 6 band ..before we start…The 800 Hz slider values equals a calculated value of 786.52 Hz which is allowable (within2%) for the targeted frequency of 800hz….and is why all mxr 6 bands from that era sound slightly different. The capacitors value can drift and even more so over time to 20% amounts and those small amounts can add up and cause drastic frequency changes.

What we are going to do is change 1 capacitor to a .047uf value and turn the 800hz slider into a 1.2 kHz slider. The calculated value from this change will be 1.25 kHz and is a respectable range.

You don’t need a vintage mxr to do this change any one will do…they are all carbon copy’s of the original anyways but parts are all different quality , hence mojo changes.

Besides you just want your mxr so it is boosting the right EVH frequency anyways..for the “ I’m the One” tune. The mod is so simple it would be very sad to see a company formed to soak people over such a simple change. So here it is. FREE
The attachment file-2.jpg is no longer available
file-2.jpg
MXR 1.2khz boost mod
file-2.jpg (87.19 KiB) Viewed 38656 times
file-1.jpg
file-1.jpg (21.26 KiB) Viewed 38655 times
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file.jpg (17 KiB) Viewed 38655 times

SteadyEddie
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Re: VH style Mods

Post by SteadyEddie » Thu Mar 31, 2011 10:43 pm

I'd say for me, definitely the 820ohm on V1B cathode, .68 bypass, and of course, .68 bypass on V2a.
I like the low filtering scheme, I keep 2x16uf on the preamps, but since I have a 50 watter I like 100uf on the mains.

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Re: VH style Mods

Post by mightymike » Thu Apr 07, 2011 2:54 pm

VH style Cascade Mod 50 watter from lidesnowi awesome tone, playing, and chassis video
http://www.youtube.com/watch?v=1gkyKZ1BdUU" onclick="window.open(this.href);return false;
lidesnowi_cascade.jpg
lidesnowi_cascade.jpg (89.02 KiB) Viewed 39799 times
From this thread
http://forum.metroamp.com/viewtopic.php?f=16&t=31707" onclick="window.open(this.href);return false;
vh junkie wrote:Yes it's the same tube.

I edited the schematic to be more correct.

The picture can be used as a layout. Use the green box that vanhalen5150 added to get your bearings the vertical green lines are where the mustards used to be!

Steps are as follows:
1) At the tube, remove the green wire from the left side of the tube
2) Unsolder the right side (green line) mustard from the lower (white wire) lug.
3) Unsolder the left side (green line) mustard from the lower (brown wire) lug,
and solder it to the right side (green line) lower (white wire lug). See where some extra wire was added? Might want to slip some insulation over this.

Once your pot is mounted to the back of the chassis (with the lugs up)...
4) Right side lug gets a 470k/500pf pair soldered to it.
5) The other side of the 470k/500pf pair is soldered to the flying lead of what was the right side mustard. Notice how this mustard is up and away from anything. The side towards the board is 285vdc :shock:, the other side is your infant first stage out signal.
6) The center lug of the pot (white wire) is connected to the tube pin where we removed the green wire on the left side.
7) The left lug on the pot might/should be connected to ground, but I don't see it.

Change the 820 ohm resistor(across the blue cap) to a 1K, and you have what is shown in the picture.

Pretty need mod! Easy to revert back to original without damaging the valuable mustards.
Here's a Layout:
lidesnowiTemplate2.JPG
lidesnowiTemplate2.JPG (54.89 KiB) Viewed 38383 times

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Re: VH style Amp Mods

Post by mightymike » Thu Apr 07, 2011 3:11 pm

Ralle One Wire Mod (Knob Mod)
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Ralle One Wire Mod
ralleevhonewirespeclayout.gif (85.09 KiB) Viewed 39795 times

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Re: VH style Mods

Post by mightymike » Sun May 08, 2011 10:43 am

Another great contribution from Good Guest. This is a great way to truly tweak your amp to taste.
SUPER MARSHALL ALL KATHODE MOD "SMAK" from Good Guest
http://forum.metroamp.com/viewtopic.php?f=16&t=35232" onclick="window.open(this.href);return false;
Good Guest wrote:There are a few mods I have done to my amp that I would like to share with the forum...This first one I posted a few years back it had some non critical errors ...but with new knowledge on evh specs etc. it's time to change it up a bit... This time you will actually get part numbers for the exact switch and it's pin out.

Of all the places to work on an amp the cathodes in the preamp provide the least voltage and are relatively safe and forgivable..so first a schematic of what we are looking at.

Image
Good Guest wrote:Just look at all the possibilities and specs to play with..what is really handy here is a cascade switch ..we'll let another forumite cover that one ...but here is my contribution..
6PosAllMshl+WireMetroSized.jpg
6PosAllMshl+WireMetroSized.jpg (109.84 KiB) Viewed 37413 times
Good Guest wrote:Here is the data sheet for the 6 position switch...part # and all. This switch is great ..I've been using ot for at least a decade and it hasn't failed . Image

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Re: VH style Mods

Post by mightymike » Thu Oct 24, 2013 10:06 pm

Here's a layout of the SMAK mod I drew up based on GG's description.http://forum.metroamp.com/download/file.php?id=16861" onclick="window.open(this.href);return false;

GG said he's used the non shorting version many times without issue, but here's the shorting (make before break) verion he provided after Vh Junkie brought it up.
Good Guest wrote:The shorting version where the contacts are not broken before they engage the next position part # is
Alpha #
SR2511-0206-19R0B-E9-S-W

Mouser #
10WW026

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