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EVJ Mods, What does what? What is best?

mrjones200x

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mrjones200x

mrjones200x

Posted
Posted

Hey there

 

Can i have it in simple terms please not really wanting to know how the mod works just what it does for sound.

 

There are so many mods available and im baffled with all the science that go's with it.

 

Simple things please like;

 

What mod will;

 

Give smoother distortion

Give better sounding gain at higher volumes

Get rid of low muddyness

Increase the life of my tubes/amp.

Make it the most versatile for more tonal varities.

 

Hope this isnt to simply explained.

 

Basically want to get the most out of my amp so it can be as versatile as possible and have a long life.

 

Thanks

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Just Strum

Just Strum

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I am clueless when it comes to amp mods, but here's a rundown of mine from the guy that did the mod.

 

In addition to below, try: http://duhvoodooman.com/VJr/VJr_mods.htm

 

This is a "version 1" Valve Jr, so first it needed to have the original design shortcomings fixed (mostly excessive hum/noise and some grounding errors). After that, I added some new features, as well as making numerous improvements to the amp's gain & tone, plus a few safety & relaibility enhancements. Many of these are included in a group of mods that have become very popular with the VJr modder community, often referred to as the "silver/gold mods". I stuck with the stock speaker and original EH/Sovtek tubes, and Strum can upgrade those later (I did, JJ's), as he sees fit.

 

Noise/Hum Reduction

 

* Convert to DC filament heating

* Add more filtering to power section

* Multiple resistor & capacitor upgrades to reduce noise

 

Reliability & Safety Mods

 

* Reduce voltage levels and bias of EL84 power tube (stock is w-a-a-a-y too hot)

* Upgrade multiple resistors to quieter/safer metal oxide type

* Replace dinky stock volume pot with a beefier 24mm pot

* Add "bleeder" resistor to DC power rail to drain large filter caps after power-down (shock hazard reduction)

 

Added Features

 

* Tone pot, patterned on Fender's Tweed-era Princeton amp

* Standby switch

* Gain boost switch

* Brightness switch

* 8 and 16 ohm output jacks (stock is 4 ohm)

 

Tone & Gain Improvements

 

* Upgrade stock output transformer to a Hammond 125DSE--multiple tonal benefits

* Multiple resistor and capacitor changes/upgrades to improve tone, clarity, gain and punch

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cGil

cGil

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...

What mod will;

 

Give smoother distortion

Give better sounding gain at higher volumes

Get rid of low muddyness

 

 

Try a 5751 preamp tube and resolve all three issues with one simple tube swap.

 

...

Increase the life of my tubes/amp.

 

This amp's power transformer was built to expect normal voltages from the wall based on old standards. If your AC voltage from the wall typically runs higher than normal (120vAC instead of 115vAC' date=' etc.), you'll need to check the operating voltages inside the amp and tweak your power supply and bias resistors as required, add a screen grid safety resistor, and add a diode to adjust the DC filament heater voltages.

 

...

Make it the most versatile for more tonal varities.

Thanks

 

Add a tweed tone pot and three-way C3/NFB switch.

 

Gil...

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m-theory

m-theory

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Watch those ebay tube buys, especially "vintage" offerings. Unless you buy from a reputable dealer that tests each and every tube he sells and stands behind them 100%, you have no idea what you'll be getting, and if it's sold as "vintage," you'll be paying top dollar for it. You should always buy tubes from a dealer that thoroughly tests and stands behind them.

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GrumpyOldMan

GrumpyOldMan

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Now to check whether they send to England!!

Ebay Item number: 310063307440 is the same (I think) Jan GE Valve (Tube) and is in England. £12 + £3 post. Seems a reputable dealer, www.langrex.co.uk, although I have not bought from them. Personally I quite like taking a gamble with the really old ones which can sometimes be picked up cheap on ebay. My own favourite pre amp valve so far is a 1960's (ish) Philips Miniwatt ecc83. I got a pair of unused ones in their boxes for £14 inc post. I do find that prices seem to have gone up a fair bit over the last 18 months or so, probably caused by all the VJ users looking for them! I also picked up a (what I think is a 1950's) Ediswan EL84 which is lovely but a bit delicate looking and also a bit smaller than a standard EL84. Paid about £4 for that one.

Of course one of the advantages of being an old guy is that I still have a box full of old valves that I have had since I was a lad in the 70's and I have several ECC83's in there including Brimar, Tungsram, Mullard, Sylvania etc. Annoyingly I had no EL84's.

Ian.

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strangedogs

strangedogs

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I highly recommend Doug's Tubes ( http://www.dougstubes.com ). They helped me retube a couple of old 60's tube amps I have (1 is my Avatar - a 1963 Ace Tone Duetto) and even found some NOS tubes (tested of course) in a shed out back they said they'd try to find that would sound awesome... They dug around on a Sunday no less and I got them for almost the same $$$ as new EH's. They help you pick tubes by the type of music you play, genres, etc. They also shipped superfast - had em in about 2 days PRIORITY MAIL. Great bunch of guys and they answer questions fast too - even a dummy gets treated with respect - I'll buy all mine from them from now on. They post frequently in Harmony Central's Forums - that's where I found em...

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m-theory

m-theory

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Personally I quite like taking a gamble with the really old ones which can sometimes be picked up cheap on ebay.

Yeah, I did too, until I got burned three times in a row with utter crap. Two VERY microphonic, very low-gain "NOS" 12AX7s and a "matched pair" of "NOS" RCA blackplate 6L6's, with one testing as new and the other testing almost completely dead. Some match. For something as flaky as tubes, I'll gladly pay someone a few extra dollars to fully test them. There are at least a few dealers online that I can think of, including Doug's, that fully test each tube and stand behind them. Well worth the extra dollars spent, imo.

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GrumpyOldMan

GrumpyOldMan

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Yeah' date=' I did too, until I got burned three times in a row with utter crap. Two VERY microphonic, very low-gain "NOS" 12AX7s and a "matched pair" of "NOS" RCA blackplate 6L6's, with one testing as new and the other testing almost completely dead. Some match. For something as flaky as tubes, I'll gladly pay someone a few extra dollars to fully test them. There are at least a few dealers online that I can think of, including Doug's, that fully test each tube and stand behind them. Well worth the extra dollars spent, imo. [/quote']

I absolutely agree but I did say the ones I can pick up CHEAP on ebay. I wouldn't spend a lot on an old valve unless I had some assurances but there are still some bargains worth taking a gamble on, my Ediswan at £4.00 ($8.00ish) being a good example. I should add though that I only play at home nowadays so I don't have the risk of a valve going on me at a crucial moment.

Ian.

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m-theory

m-theory

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I absolutely agree but I did say the ones I can pick up CHEAP on ebay.

Cheap crap is still crap, but, it's your money. It's usually the cheap ones that are total crap. All I can do as the voice of experience is offer my voice of experience. I can't force anyone to pay heed that doesn't want to!

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GrumpyOldMan

GrumpyOldMan

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Cheap crap is still crap' date=' but, it's your money. It's [b']usually[/b] the cheap ones that are total crap. All I can do as the voice of experience is offer my voice of experience. I can't force anyone to pay heed that doesn't want to!

That's my point, USUALLY, but not always! Hence my use of the word GAMBLE, that means you know you might lose out but you also might get a bargain. Because something is cheap it isn't necessarily crap (the Valve Junior is an excellent example of that) and in the same way something that is expensive isn't always great. Most, if not all the valves I have picked up on ebay are from people who have found them in their parents cupboards or drawers or garages etc and they have been there for years. Usually they were put away because they were good or they'd have gone in the bin but the finder hasn't got a clue about what they are. These are the valves I am talking about and can sometimes be picked up for very small amounts, I have bought valves for as little as £2.00 ($4.00) and they have been great.

Incidentally, I got my first valve amp, a Shaftsbury Suitcase model in 1971 and traded it for a Vox AC100 a year or two later so over those 37 years I think I have gained enough experience to know what I am looking for even if I don't know its condition until I get it! I do appreciate where you're coming from though and people should be aware that there is some duff stuff out there and some ruthless sharks prepared to take your hard earned money for it.

Ian.

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TWANG

TWANG

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I got an old grundig console stereo at auction for five bucks..

wanted the mahogany!

pulled out two Seimens tubes.. ECC81 and ECC83.

that's a 12at7 and a 12ax7

I'm still using both of them,months later, and they are still my fave tubes.

I thought one was shot, but it turned out to be my mod.

 

the old radio collectors often don't show up for stuff like that.. they really don't want to bother going to auctions just for an off chance on

a tube or two that probably wont be any good anyway.

So that was a bit of luck, no doubt, on my part.

 

Likewise, I just got some solid wood panels, from someone's unfinished project.. *roll top desk, I think, got the roll top, too*

six of them.. enough for three top panels of a vj cab each..

enough in fact for all four sides each, I think.. haven't checked but I know they are deeper than the vj and a bit wider than three top panels, too.

 

that's five or six really really nice looking epi vj cabinets after I get done with them. for five bucks.

 

go to auctions. It's fun.

tools are typically sold for 1/4 what you'd pay for the cheapest metal chinese tool.. and last longer!

 

AND DON'T FORGET

that's where I just got my

"OUTER SPACE CADET"

button which I put on my guitar strat right away.

(a little button I found in a .50 cent box of stuff. which included two perfectly good box knives, twenty dice, a naked lady pencil, and a cool little

fluid type lighter for my sons collection. It has a rocket ship and outer space cadet on it. very hip I think)

 

cheap is cool!

and smart.

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