Mercury Magnetics Valve Junior

[Bill Moore]

A friend sent me a project a few weeks ago that he had inherited, so I finished it. It is a Epi Valve Jr head, and a MM upgrade kit. It has beefier transformers, (of course), and a choke, and a few circuit mods, including adding a 6V6 power tube.
After I assembled it, I plugged it into a K130 cab for testing, waaay to bright. I remembered I had a Peavey cab with a Sheffield 12 in it, and that did tame some of the highs. I used my Tele, with Texas Special pickups, but anything past 1/3 volume, started breaking up. At 1/2 volume, very nice sustain/overdrive, and 3/4 volume will runaway into feedback, if you let it! I took it down to what passes for a music store in my little town, to let the R&R guitars play with it, its too gainy for me!

[Dave H]

The upgrade kit must have cost more than the original head. It looks like the EL84 and 6V6 are in parallel and there's a bright circuit (R and C in series) across the 1M resistor feeding the vol pot.

[Bill Moore]

From what I have seen The amp head was around $150, and the MM upgrade kit was $300!
I debated tweaking it, (maybe adding a switch to bypass the "bright" add on, and even a switch to put the 6V6 in "standby".) I think I will pass it along to someone who wants it as is.

[olddawg]

From what I have seen The amp head was around $150, and the MM upgrade kit was $300!
I debated tweaking it, (maybe adding a switch to bypass the "bright" add on, and even a switch to put the 6V6 in "standby".) I think I will pass it along to someone who wants it as is.

Honestly you can find them all day long on CL for $80 or so. I use one to drive my talk box. BUT.. I used it for years into a "1x12 open back cab loaded with an Eminence. With an OD pedal and a compressor I played with a live drummer all of the time. Stock, even down to the Chinese tubes. Mine wasn't particularly bright. I used a Strat mostly on the bridge pickup. I like these little amps as is. I'm not so sure what a MM OT is going to get you other than bragging rights, lol!

[Bill Moore]

I know you can get stock used one's cheap, I contemplated using one for a stand alone reverb conversion.
There is a little more involved in the MM upgrade than an OT!
Here is a copy of the upgrade details.
http://www.danbecker.info/guitars/20...anual%20V2.pdf

[olddawg]

I considered doing a stand alone Reverb conversion myself. Then I compared a vintage Fender unit to a modern pedal and and had to ask myself why? Lol. Same thing with these conversions. It’s a simple 5 watt amp. I think you will get more versatility out of the speaker you use and the pedals you choose. I’ve said this before. I had an old ratty 1960 Ampeg Rocket amp loaded with an Eminence. I would set the stock VJ behind it and simply plug it into the speaker. People would freak out about my “vintage amp tone”, lol. The Rocket was basically an open back speaker box.

[g1]

I know you can get stock used one's cheap, I contemplated using one for a stand alone reverb conversion.
There is a little more involved in the MM upgrade than an OT!
Here is a copy of the upgrade details.
http://www.danbecker.info/guitars/20...anual%20V2.pdf

Thanks for posting that Bill, I haven't studied the schematic but this is definitely more substantial than a simple TX upgrade.

[alexradium]

yes,that mod with the bright cap is definitely different from stock,i had one of these amps for fairly long time and its pretty good quality,tried all the possible mods and ended up with a Bitmo tone control in front of the volume and smaller cathode bypass caps,that allowed me to obtain any degree of brightness,a fairly good clean tone without losing too much bass and a pretty good overdriven sound involving the power tube saturation.
Obviously if you want more control over the total gain you can include a feedback champ style,but to me it gets too sterile for a guitar sound.

[Justin Thomas]

I find it amusing to see they refer to "generic EL84" & "generic 12AX7" tubes... As if there were anything else that a modern amp would come with? And if I'm not mistaken, any modern-production tube is pretty "generic?"

Not saying the mods don't sound good (never tried one of these amps) but I like some of the marketing facts...

Justin

[nosaj]

I find it amusing to see they refer to "generic EL84" & "generic 12AX7" tubes... As if there were anything else that a modern amp would come with? And if I'm not mistaken, any modern-production tube is pretty "generic?"

Not saying the mods don't sound good (never tried one of these amps) but I like some of the marketing facts...

Justin

Well when you say generic you're not giving a nod to China.

nosaj

[g1]

Bill, was there something that you didn't like about post #8 that you could comment on?

[J M Fahey]

Bill, was there something that you didn't like about post #8 that you could comment on?

I had the same doubt when I saw the negative

Unless it was a mistake and Bill removes it

[Justin Thomas]

Some of us (Tom Phillips & myself) have noted that on a tiny phone screen, sometimes it's hard to hit the proper thumb with our big thumbs. Besides, I'm a bass player mostlyv- how much finger coordination do you expect from me?

Justin

[Bill Moore]

Sorry about that! I'm using my tablet, and with the slow wi here at home, I didn't see the negative!
(of course I meant a positive!)

[J M Fahey]

I find it amusing to see they refer to "generic EL84" & "generic 12AX7" tubes... As if there were anything else that a modern amp would come with? And if I'm not mistaken, any modern-production tube is pretty "generic?"

Not saying the mods don't sound good (never tried one of these amps) but I like some of the marketing facts...

Justin

Oh, I understood it as: "donīt spend $300 on NOS tubes ... but on MM iron instead "