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Post by LVF on Jul 16, 2020 19:31:52 GMT -5
Finished up the repair/mod on my BJr a while ago and it turned out great. I didn't know what to expect the first time I powered it up. I had visions of an impending nuclear waste land but, that didn't happen. What happened was a whole new amp came alive. That Fromel mod really opened this amp up. I wasn't sure what to expect. It was more than i thought it would be. Also, no unwanted noise. Absolutely silent. Just the sound of the guitar coming through. Now, I'm thinking...supercharger! Not really but, that's what doing this work reminded me of, supin' up a hot rod. Anyway, there you go. I started this project because of a spooged cap and ended up with a completely modded amp. I hope I'm not the only one that can see this pic :
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Post by stratcowboy on Jul 16, 2020 19:52:55 GMT -5
Picture is visible. And it sounds great with how things turned out. Nifty!
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Post by LTB on Jul 16, 2020 22:06:44 GMT -5
Looks like you made a cool little amp cooler! Glad it worked out for you
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Post by LVF on Jul 17, 2020 10:26:05 GMT -5
Thanks guys but, I have to tell you, if you remember that transmission commercial from years back with that dude that 'ain't never done a transMISHYoon afore', that's me. This was my first attempt at working with a PCB board and it was actually pretty easy and fun. But, you need to do some research if you're like me. When I turned on the switch for the first time, I didn't know what to expect. Visions of my little amp vaporizing. Just glad it came out as good as it did. Next week , I'll have a good way to compare this amp to another BJr I ordered up. The new one is a NOS BJr. in tweed. I want to run in stereo but, I wanted each amp to be the same. Should be interesting.
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Post by stratcowboy on Jul 17, 2020 10:56:17 GMT -5
It will be interesting to hear your comparison review.
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twangmeister
Wholenote
Posts: 349
Formerly Known As: Twangmeister
Age: 72 and fading fast.....
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Post by twangmeister on Jul 18, 2020 8:01:30 GMT -5
Uhhh.....was it just me or was the bad cap labeled in reverse?
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Post by LVF on Jul 19, 2020 11:26:33 GMT -5
Uhhh.....was it just me or was the bad cap labeled in reverse? Mirrors tend to do that. Something that I've been wondering about since I finished up was one of the steps done in this process. Maybe an electronic wizzaroo can 'splain to me just what it does. That is, bridging two contacts on the mid pot between #'s 2 and 3 contacts, closests to the Master pot. What does it do for the mid pot?
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sirWheat
Wholenote
For a better future, play Stevie Wonder for your children.
Posts: 323
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Post by sirWheat on Jul 19, 2020 13:29:01 GMT -5
Isn't that what allows you take the mids out of the circuit?
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Post by LVF on Jul 19, 2020 15:15:04 GMT -5
It appears the the mid circuit still is active and functioning as it did so, I'd say no.
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sirWheat
Wholenote
For a better future, play Stevie Wonder for your children.
Posts: 323
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Post by sirWheat on Jul 19, 2020 15:42:26 GMT -5
As I recall via BillM, that mod allows you to remove the mids when the knob is turned to zero.
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Post by LVF on Jul 19, 2020 16:36:09 GMT -5
Ah, OK. That makes sense so, I guess that must be the answer. I'll have to try that out and see what happens.
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Post by LVF on Jul 21, 2020 20:40:50 GMT -5
Got BJr #2 today from the big brown truck and when I opened the box and looked at it for the first time I thought about my 59 Bassman and thought they look almost the same and another thought came to mind. It's Mini Me! I don't ever name my amps 'cause I think that's taking the whole naming things too far but, with this amp, I make the exception. For now and for all time, it shall be, Mini Me. I also attempted to do a quick A/B between the Jrs using my Whirlwind A/B pedal but, it wouldn't work. Why didn't it work? Because it too had a blown capacitor. It worked on the A side but, not on the B side so, I opened it up and started doing some test when I found the cap that had spewed. Not being discouraged by this finding and having bought caps to repair my Black BJr, I found a cap that was 'close' to what the pedal had and stuck that one in it. Long story even longer, put it back together and I'm back in business again. However don't have enough info to give a good A/B at present so, the only thing I can say is that their are some differences initially but, nothing negative. I'll give them a good work over tomorrow and I'll see what comes up. With that in mind, I should probably put that up on the other amp forum. Stay tuned if you're interested.
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Post by stratcowboy on Jul 21, 2020 22:14:23 GMT -5
Stay tuned if you're interested. Yes. Interested.
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Post by Riff Twang on Jul 21, 2020 23:45:23 GMT -5
Me too.
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sirWheat
Wholenote
For a better future, play Stevie Wonder for your children.
Posts: 323
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Post by sirWheat on Jul 22, 2020 6:33:33 GMT -5
Mini "B"...
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Post by LVF on Jul 22, 2020 12:28:06 GMT -5
Before I move on to the comparison of these to like amps, I thought I put up some boring stuff. This pic shows the PCB boards from both amps with the top one being the old, before the mods. I put this together so I could study some differences. Looks like they couldn’t decide what color to go with so, they ‘camouflaged’ the new board in green and beige. In the next pic, you may see another difference. They are still using the caps from ‘IC’ (same, original specs) and I note that the board has two fuses instead of one like on the other BJr board. I also note two raised resistors on this new board at R47 and 48. Heat issues? Also, in those places, the resistors have different values where on the other, they have the same values. (I, myself, have forgotten how to read the values on resistors so, maybe one of you electronically electronic engineer types could chime in ) Wonder what the story is behind that? Some kind of improvement? Thoroughly bored yet? There's more. Ah yes, I couldn't let this go without noting that: 'All your product in California are cancerous. Maybe it's more like: 'All your politician in California are cancerous. Is there not one thing produced in California that avoids this tag? At any rate, pardon my ignorance if there is real danger here. Anyway, this took all morning to put together and so, my amp comparo will probably take longer and...it will be in the other amp forum. Stay tuned.
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Post by LTB on Jul 24, 2020 15:26:59 GMT -5
R47,R48,R49 are same values on both boards
2.2k, 10k, 10k respectively Yes they apparently raised them off R47 and R48 off the board for better cooling
Also I see 2 fuses next to one another on both boards. Green board it is more readily seen but is there on brown board never the less
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Desoto
Quarternote
Posts: 31
Formerly Known As: Roger Ball
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Post by Desoto on Aug 28, 2020 14:06:44 GMT -5
I've just completed the Fromel update to my 1998 Blues Jr. and I'm impressed. Before this thread came up I was planning to replace the original power supply caps as well as replace the flimsy input jack. I also wanted to address the bias situation to cool down the power tubes. The update does all of that and more. First impressions are that the amp is much quieter, has more "clarity", and a really nice improvement in the reverb.
I was a little cautious since I've not worked on a PCB amp before but I took my time and everything went well.
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