Fender Blues Jr - Mods

[daleykd]

Hey all.  A while ago, I bought a Blues Jr.  It's my first small tube amp (I have a Marshall JCM2000 DSL100), and like most DIYers, I want to mod it.

I ordered the basic kit from Bill M back at Thanksgiving, and have heard NOTHING.  I've sent numerous emails, and keep an eye on his website.  The problem is, the basic mod doesn't appear to be documented.

Even if the bass and mids are set to 0, and treble turned up, it's still waaaaay too bassy/muddy to me.  Everyone talks about too much 'sparkle,' and I feel as though I get ZERO.

Anyone have any recommendations aside from "burn it, sell it, or whatever."  I want to make this small amp great, just like the ones I've heard at my friends' houses.

TIA,
Kyle

[matmosphere]

Did you buy it new? If it's that muddy maybe there's a problem with it. Have you tried other Blues Juniors to compare the tone?

You could always try different tubes or a different speaker.

[EBRAddict]

It took him a long time to ship my Blues Jr. mod kit. Like 4 months, never responded to follow up. Another guy at work modded his and said he had the same experience.

[daleykd]

Did you buy it new? If it's that muddy maybe there's a problem with it. Have you tried other Blues Juniors to compare the tone?

You could always try different tubes or a different speaker.

Nah, I bought it used.  I have played my friend's.  It's gorgeous and the reason I bought mine.  I did put in new tubes, and that seemed to have little effect.  I was hoping to mod the PCB before a new speaker, but I'm tempted to try a new speaker ASAP.

It took him a long time to ship my Blues Jr. mod kit. Like 4 months, never responded to follow up. Another guy at work modded his and said he had the same experience.

Yeah, I'm trying to be gracious; I know he's been through a lot, and who knows what's going on now.  But, man... it's just some caps and resistors.  If it's going to take 4 - 6 months, just tell us what the mod is, and let us do it.  I wish someone would disseminate the info provided in the purchased kit.

[TNblueshawk]

I know I've read a thread or two over at BYOC, maybe a year or two ago, that had a link and or documented on how you do the mods. Sems like a mod over there has done and or provided the link or something. You could try the search button over there.

[oldhousescott]

I suppose you're aware of Bill's health issues. That's not an excuse for poor business practices, but just an acknowledgment of reality.

Regardless, the easiest mod is the TwinStack mod described on his site here. With the stock tonestack, you can never turn the bass off as the mid pot, even at full ccw, keeps plenty of bass intact. By adding the jumper, you convert the tonestack into a more typical BF style, and when you turn the bass full ccw and mids down, the bass is gone *poof*.

If you find, after the mod, the speaker is still too woolly, check out the WGS G12C or Eminence Legend 1275. Both very affordable.

[daleykd]

I know I've read a thread or two over at BYOC, maybe a year or two ago, that had a link and or documented on how you do the mods. Sems like a mod over there has done and or provided the link or something. You could try the search button over there.

I'll do some searching there; appreciate it!

I suppose you're aware of Bill's health issues. That's not an excuse for poor business practices, but just an acknowledgment of reality.

Regardless, the easiest mod is the TwinStack mod described on his site here. With the stock tonestack, you can never turn the bass off as the mid pot, even at full ccw, keeps plenty of bass intact. By adding the jumper, you convert the tonestack into a more typical BF style, and when you turn the bass full ccw and mids down, the bass is gone *poof*.

If you find, after the mod, the speaker is still too woolly, check out the WGS G12C or Eminence Legend 1275. Both very affordable.

Yeah, I'm aware of his health issues, and that's why I try to afford grace.  My mom recently died from pancreatic cancer, so I know what cancer does.

Your explanation of the TwinStack mod is the best I've heard.  I didn't realize that, and definitely planned on doing it when I got the kit in.  Now, I may just go ahead and do it.

Someone in my local music exchange group was selling a Red White and Blues speaker for $50.  According to Bill M, that'll greatly help with the high end.  I'm tempted.

[Bret608]

Which version BJ is yours--the cream board or the old green board? I ordered and installed the green board kit on my old '96 BJ, as well as putting in a Switchcraft jack and swapping out the remaining 22uf power supply caps. I got fairly lucky on how quickly I got mine as it was before he got ill. The instructions were really good but some of the parts numbers may be different than what I have if you've got the cream board.

Besides the very useful Twin Stack mod (and the explanation of what it does provided above is dead-on), the mods basically increase the main 47uf power supply cap to 100uf (Bill provided a low ESR variety); bass cap is increased to 0.1uf, mid cap is dropped down to 0.015uf; the two main coupling caps are swapped out for Orange Drops of the same value as the original (0.1uf, I think). The addition of a bias trimmer is really the big one. All this adds up to make it sound like a really good Princeton reverb or something. If this makes sense, it has more bass on tap (and I have to actually dial it back a bit), but it sounds way clearer and punchier.

Let me know if you need any info from my set of instructions! 

[daleykd]

Which version BJ is yours--the cream board or the old green board? I ordered and installed the green board kit on my old '96 BJ, as well as putting in a Switchcraft jack and swapping out the remaining 22uf power supply caps. I got fairly lucky on how quickly I got mine as it was before he got ill. The instructions were really good but some of the parts numbers may be different than what I have if you've got the cream board.

Besides the very useful Twin Stack mod (and the explanation of what it does provided above is dead-on), the mods basically increase the main 47uf power supply cap to 100uf (Bill provided a low ESR variety); bass cap is increased to 0.1uf, mid cap is dropped down to 0.015uf; the two main coupling caps are swapped out for Orange Drops of the same value as the original (0.1uf, I think). The addition of a bias trimmer is really the big one. All this adds up to make it sound like a really good Princeton reverb or something. If this makes sense, it has more bass on tap (and I have to actually dial it back a bit), but it sounds way clearer and punchier.

Let me know if you need any info from my set of instructions! 

Sent from my SM-G920V using Tapatalk

[daleykd]

Sorry, wanted to get the pics uploaded.

It's a Rev C green board.  The tubes aren't even 3 months old.  I want to fix the reverb issue with the green board, and I'm told the tank may have an issue.  (I haven't investigated yet.)

[matmosphere]

I'd say if you got it used AND it sounds completely different from others you've used you need to make sure everything is right with the amp before you mess with modding it. If there's something wrong with it then it's probably not going to sound any better after the mod and it might be harder to figure out how to fix it.

[brucer]

The Billm mods were great for my Blues Jr.  Their transformer was also a big improvement for my Princeton Reverb reissue.  That said, your experience is the same as mine re: customer service: looooooonnnnggg wait times for product and little or no communication except when they need to reach you.  The exception seems to be if you have a tech problem while making mods you've purchased.  They're pretty quick to respond on that (at least in my experience).  Per other posts, I understand the delays are due at least in part to Billm's health issues ... which I'd wish on no one.  I think his son Andrew now does most work, including packing/shipping parts.  So ... I guess it's sort of buyer beware on the timing front for what many people like in terms of outcome.  There are other options (e.g. http://www.fromelelectronics.com/collections/amp-mod-kits), but I have no experience with anyone but Billm and my local amp tech.  I dunnno if all that's helpful or not ... 

[culturejam]

I wish someone would disseminate the info provided in the purchased kit.

After all this time, I can't believe nobody has posted the information.

[jprizz]

I'll have to dig thru my stuff and see if I still have the instructions. I dont remember what mods I did but here is a pic of mine - obvious stuff like power filter caps, a couple orange drops, and the added trim pot for biasing... that was the hardest part

[pryde]

I mod tons of these for people. IMO here is order of importance:

1: bias, need to cool it down as the EL84s are absolutely cooking and damage the pcb.
2. speaker change will make the biggest difference in tone for you (WGS G12C good choice)
3. parallel another 47uf reservoir cap on, it helps the bass when you turn it up
4. Amp should be sounding way better. If still not pleased then do the tone cap mods