New Epi Valve Junior came in today

[Rusty]

Originally Posted by Pepi

Be sure and try the Hammond OT upgrade too. This made all the difference in mine.

what does it do and where's the link for info?

Originally Posted by Pepi

Be sure and try the Hammond OT upgrade too. This made all the difference in mine.

How difficult/easy was The Hammond OT to install? I see they are only about $32.

Thanks,
Jake

[Pepi]

Took me around 1 hour to install the new Hammond 125DSE. I had to drill another hole due to the bigger OT base. Easy mod if you have a small amount of tube amp knowledge. I've done a lot of mods to my VJ, Tone control, Master Volume and a gain switch but this mod made the biggest difference. The bigger Hammond OT will bring out the lower end of the frequence response of the VJ. I love this little amp!

http://www.hammondmfg.com/125.htm

Originally Posted by Pepi

Took me around 1 hour to install the new Hammond 125DSE. I had to drill another hole due to the bigger OT base. Easy mod if you have a small amount of tube amp knowledge. I've done a lot of mods to my VJ, Tone control, Master Volume and a gain switch but this mod made the biggest difference. The bigger Hammond OT will bring out the lower end of the frequence response of the VJ. I love this little amp!
http://www.hammondmfg.com/125.htm

Cool! Did you have a wiring diagram for the OT or instructions you can share?

I have my VJr. head apart and am ready to start the mods when my parts arrive ... today I hope. I'm going to perform these:

R1 1meg 
R2 10K 
R6 shorted out 
R7 replace with 500K pot for gain control 
R8 1.5k 
R9 680 ohms 
R14 240 ohms 
R10 1K 3W 
C3 3.3uf  
C4 3.3uF  
C5 1000uF

Also well as install a standby switch.

NOTE: R10 is not needed in Revision 2 VJr. Combos, or the Head version.

[Pepi]

You want to use the 5000 ohm secondary lines. The EL84 is happier at 5000 ohms. The stock OT is 7000 ohms.

Primary:
on the 125DSE are the Brown and Blue primary wires. These go to to the output from the EL84 tube. Some will say it makes a difference which one goes where but it doesn't. I tried both ways and got the same results. Now, on a push-pull amp it does make a difference.

Secondary:
For the 16 ohm jack wire the White wire on the 125 to the PC board where the 16 ohm jack is.

For the 8 ohm jack wire the Yellow wire on the 125 to the PC board where the 8 ohm jack is.

For the 4 ohm jack wire the Greem wire on the 125 to the PC board where the 4 ohm jack is.

Black wire goes to the jack PC board where the exsisting black wire is.

DONE! Kick @ss 5 watts ...

Originally Posted by Pepi

You want to use the 5000 ohm secondary lines. (snip)

Super! Thanks Pepi!

Jake

[Pepi]

Originally Posted by BlueJakester

Super! Thanks Pepi!

Jake

No problem. One other thing I've found out with mine. My line voltage was causing the EL84 plate to run around 330 VDC. I put a 10 watt 10 ohm resistor on the 110v in to drop the plate voltage down. This took a lot of the ice picky tone out of the EL84 for me.

I completed my mods as listed in post #24 above. Wow! What a difference! Absolutely amazing improvement for about $10 and a couple of hours with the soldering iron! Installed a fresh set of JJ's from Eurotubes too.

All of the test playing I did was with guitars direct into the amp. Installed a 500K pot for gain control, works great! Nice to have a standby switch too. I get excellent break up and sustain.

The only thing that puzzles me is why Epiphone/Gibson doesn't build the amp this way in the first place? A few differently rated resistors and capacitors, a toggle switch and a potentiometer. Like I said, less than $10. IMHO they could build it right the first time, and sell it for $149 and it would still be a bargain. Go figure

I'll probably play the amp this way for a while and install the Hammond OT later if I want to tinker with it some more. But for $110 (+ $14 for tubes) this is a very nice sounding 5 watt amp!

Cheers!
Jake

[Greg Jones]

Cool thread all.

The thread at 18watt.com was more than I could take so I ordered me a head today.

Can't wait to tweak away on her.

[Rusty]

Originally Posted by BlueJakester

I completed my mods as listed in post #24 above. Wow! What a difference! Absolutely amazing improvement for about $10 and a couple of hours with the soldering iron! Installed a fresh set of JJ's from Eurotubes too.

All of the test playing I did was with guitars direct into the amp. Installed a 500K pot for gain control, works great! Nice to have a standby switch too. I get excellent break up and sustain.

The only thing that puzzles me is why Epiphone/Gibson doesn't build the amp this way in the first place? A few differently rated resistors and capacitors, a toggle switch and a potentiometer. Like I said, less than $10. IMHO they could build it right the first time, and sell it for $149 and it would still be a bargain. Go figure

I'll probably play the amp this way for a while and install the Hammond OT later if I want to tinker with it some more. But for $110 (+ $14 for tubes) this is a very nice sounding 5 watt amp!

Cheers!
Jake

Can you post some good details of the mods you did. Pictures or diagrams, parts, and straight forward "english". I'm not firmiliar with this stuff, so I need it in non-geek terms.
Thanks