Monday, June 1, 2009

The Fender Blues Junior revisited

I’ve had a couple of close encounters recently with Fender Blues Juniors used as harp amps and I was impressed enough that it warrants a blog update. As many of you know, I have been skeptical of the BJr in the past because its high gain guitarish nature makes it unsuitable for the kind of crunchy harp tone I like. Also, newer amps powered by EL84 tubes don’t produce the tone I prefer.

A friend who is a beginner at amped playing asked me to help set up his BJr. The only mod we made was trying a 5751 in place of the 12AX7 tube in the preamp socket. We fiddled with the controls and got a very satisfying tone with these settings:

-FAT switch Off (It is evil for harp)
-Volume on 50 percent.
-Bass dimed
-Mids rolled off a bit, say 40 percent
-Treble rolled off all the way
-A little reverb, maybe on 2
-Master control is used to set the amp’s loudness.

The tone was surprisingly good and feedback resistant. There was plenty of volume. While the tone was not as crunchy and organic as I like, I would totally gig this amp with no problems. It is worth noting that it sounded a lot better with my gig mic – a Greg Heumann modded Peavey Cherry Bomb bullet mic with Shure CM element – than it did with another bullet mic I tried. The Cherry Bomb has a deeper tone due to it’s bigger cavity, thereby ameliorating some of the BJr’s brightness.

We tried swapping the speaker for a Weber Sig 12 ceramic with smooth cone but it sang with ghost notes, so we put the stock Fender/Eminence speaker back in. I’m sure the BJr could profit greatly from a speaker swap, but I think it needs to be a ribbed cone speaker to quiet the cone cry. A vintage Jensen P12R would be good, I think…

The next step for this amp is a 12DW7 tube in the phase inverter socket to give it slightly more grit. I’ll report on the results.

The other Fender Blues Junior I tried belongs to Victor, a guy known to many harp players around Denver and across the country. I played his BJr at the Boulder Outlook blues jam last week. He has modified the amp in ways I can’t completely describe, telling me it has a new gain stage. I know it has stock tubes and speaker. It sounded great, with more body and thickness than your standard BJr. When Victor played it with his EV RE-10 mic it was clean and pleasing. When I played it I found it needed a bit of pushing to get it to tip into warm distortion, but it was all very controllable and nice.

If you want details, ask Victor. He is also a first rate harp tech. He replaced a blown reed in my Hohner Marine Band Deluxe harp in A, and chamfered, arced, embossed, and tuned the harp. It is the best-sounding, nicest playing harp in my collection. Victor is an artist.

UPDATE: Here is a clip of Colorado blues harp player Mojo Red playing through a Blues Junior with his band TeraBlue. He retubed his amp using JJ tubes (12AY7 in V1; 12DW7 in phase inverter socket) and swapped in a Weber 12A100 smooth cone alnico speaker. Nice tone!

3 comments:

mstahl16 said...

My BJr. delivers excellent tone in it's stock form. Caveats: 1) It sounds best with with a bright JT30crystal, my two black labels crs, two white label cms and a mim cm do not sound nearly as good. 2) I agree that volume at 50% is definitely the starting point, I keep treble and mid at about 4-5, bass at about 6. 3) Mess with the reverb, sometimes for reasons unclear you get the sweetest Little Walter horn tone for no explicable reason at different reverb positions. 4) To date every MIM BJr that I have tried does not have the same tonal qualities as my USA model. This includes some of the fancy special editions with the replacement Jensen. The circuit boards are colored differently but other than that I cannot explain the reason for this, maybe I just got lucky. 5) This is my favorite pratice amp and it works well for small venues such as house parties. It is very headroom limited though, you will find yourself blowing your brains out if the guitar player is playing anything more than about ten watts. 6) The BJr. makes a great guitar amp too but given it's single channel nature it's a bitch trying to play both harp and guitar at the same time as guitars, especially humbuckers, want that treble turned way up. I have spilled a number of drinks for that reason.

Joe's Blues Blog said...

Victor's a cool dude. I met him a couple of times at Dan Treanor's jam at the Outlook. Since, it had been a year between my visits, I was surprised that he remembered me.

He's a nice guy and he built Dan's 5E7M Bandmaster. It's a great amp!

Mike Fresquez said...

Try using ABY switch to go back and forth from guitar to harmonica.