blues junior in the house

[popthree]

i'm doing a 'reunion' show next month with my old band mates of 20 years ago. the only amp i had around the house is a little fender champ that i love...but figured i might be wise to get something with a bit more oomph for this show. initially i picked up a 2nd hand hot rod deluxe and liked it fine for a week or two.. then the love affair ended and i decided i couldn't deal with the uber touchy volume knob and the overall freaking loudness of the amp..thinking power attenuator..blah blah.. so i swapped it off and got a blues junior and some boot in return.

this BJ has a couple of the BillM mods done to it.. one being the twin mod... tone stack mod and something about power stiffening capacitors..not sure what that does.. but anywho.. the little amp sounds pretty darn good. the reverb is weird.. but i don't use spring reverb anyway.. so no issues there.

just wondering.. what if any other mods should i consider ? i believe the amp has the stock tubes.. would i get a big benefit from reloading the amp with one of the JJ kits from eurotubes ?

it also has the stock speaker..... should it be upgraded ?

the little amp sounds pretty good right now actually.. maybe i just go with the 'if it aint broke, don't fix' philosophy ..eh ?

[Hiker]

What have you learned about the loudness of the other's amp rigs, or the acoustics of the meeting place for the 'reunion'?

The stock speaker takes awhile to wear in unless you're cranking the volume.

[moodus2006]

If it works - Don't mess with it! It is a great little amp and for good reason.

[Billm]

Changing tubes would do next to nothing for the amp unless the existing tubes are badly worn and dull sounding.

If you send me a photo of the circuit board I can tell you exactly what's been done to it, but it sounds like the basics are covered. You can push the amp one way or another with a different speaker, but as Moodus says, if you like the tone, don't mess with it.

The power supply stiffening cap compensates for some of the shortcomings of the stock output transformer. It reduces bass distortion and flubby/farty tone, reduces intermodulation distortion, where your low-string harmonics "infect" the upper strings--better note separation.

[popthree]

hey thanks for the offer Billm... i'll do that.

[popthree]

is this pic good enough ? i can take more and email to you if that would be easier.

[The O.K.]

What a wise decision you made! I had a Hot Rod Deluxe before. I liked it, but once I saw how much more I can push the Blues Jr., I have decided this is the better amp.

I liked the stock speaker, but curiosity got the best of me. I decided to upgrade with a Texas Heat. It made the amp sound better. I keep telling myself I am going to do the BillM mods but haven't gotten to them yet.

I assume that you haven't been gigging of late since all you had was a small Champ. Hopefully the Blues Jr. along with your reunion will inspire you to join a band and get out and play again, if you already aren't. My little Blues Junior loves to get up in front of people and show what he can do.

[Billm]

It only has the bare minimum--tone stack and power supply stiffening. The bias isn't adjustable, so the kit probably didn't come from me, or the previous owner was lazy. It may have a cooler bias resistor in R52; can't tell from 30,000 feet. :)

[popthree]

Billm, i'm having some overheating issues with the amp :-)

i verified with the original owner that he did buy your kit, but he did not install the bias pot.. he just did the tone stack stuff, and power stiffening. could doing the power stiffening without the bias mod affect the amps bias in such a way that perhaps the tubes might start running hotter than normal ?

[Billm]

No, the power stiffening cap does not change the bias and does not cause the amp to run hotter. It just keeps some power in reserve for the low, loud notes and reduces intermodulation distortion.

If one tube is redplating and the tube is good, there's a bad connection to pin 2. Either the socket is loose (here's the fix)

http://billmaudio.com/wp/?page_id=171

or the solder joints on the socket to the tube board are cracked. Worst case: a broken wire in the ribbon cable where it joins the main board. In your case, since it comes and goes, it's likely the socket or a solder joint.

It's probably running hot, though. Most do. And EL84s are all over the place bias-wise, so adjustable makes sense--you can run as hot or cool as you like.