Blues Jr. Amp Pop/Buzz

[Cagey]

Sometimes ribbon cables are used to make wiring/assembly easier by removing the need for the assembly person to make any decisions. Everything will only line up one way, so it's difficult to make mistakes. If there's no anticipated need for modularity for future service, then connectors may not even be used - the ribbon is just soldered in. Sounds like that's what you have there. It's actually better, inasmuch as connectors can be a failure point. Hardwired/soldered connections are more reliable.

Unless that ribbon is really restricting your access to those sockets, you don't need to remove it. Just be careful when you're poking around in there with the soldering iron that you don't inadvertently contact the cable and burn up the insulation. When your attention is focused on the tip of the iron, it's easy to forget that the shaft behind the tip is hotter than dammit as well and will also burn whatever it touches. Usually it's your nose that tells you you're doing something wrong before your eyes do. Burning thermoplastic stinks  :laughing7:

 

[mayfly]

It should unplug at either end.  From the picture the plug is buried on the other (inaccessible) side of the tube board, but I suspect you can just unplug it from the other board.

Hmm, from what I can see it appears to be soldered at both sides...

This may be the proper time for a tactical retreat; I'm not really feeling comfortable that I won't mess something up with my soldering

If that's the case I'd just work around it. or pull the board to adjust access to the connections you need to re-do.

 

[ragamuffin]

So I worked up the balls to stick my soldering iron in there, and with just a tiny bit of charing on the ribbon cable I was able to reflow all the power tube joints. I plug my amp back in, and its noticeably louder but more importantly buzz free!

Thanks Mayfly and Cagey, you guys saved me what probably would have been a costly trip to an amp tech :headbanging:

 

[mayfly]

Excellent!  Glad to hear that it worked out.  :headbang:

You know, I wonder if there is a market out there to 'rebustify' some of these PCB tube amps.  For example, those tube sockets were just held there by the solder joints instead of being bolted solidly to something.  As we found out, it's a recipe for failure over the long term. 

The Blues Jr. circuit is not terribly complex.  Should be pretty easy to work up a couple of eyelette boards for all the components on one of those.  And add a useful master volume while you're at it!

 

[Cagey]

Isn't that basically what the "boutique" amp builders are doing? There's not a whole lot new under the sun on tube amp world. They're all just repackaged legacy circuits with a tweak here and there, built so they won't fall apart under normal use. 

 

[mayfly]

But - there are a lot more Blues Jrs, and Blues Jr players, out there than most boutique amps!  Making someone's existing amp better is a much easier sell than trying to sell a brand new amp.  Besides, the transformer, chassis, tubes, speaker, cabinet, have already been paid for!  It's a cheaper option - and one that promotes recycling to boot. 

 

[Cagey]

Yeah, makes sense. I wonder if an "upgrade kit" sort of thing would be viable? Sell that to the DIY crowd, and sell the upgrade as a service for those who don't own a slobbering iron.

 

[mayfly]

Yea that's exactly the sort of thing I was thinking.  A DIY board replacement with point to point boards and quality components.  Fix the mechanical issues and upgrade the circuit as well (post phi master, dual bias pots, etc)

Hey Ragamuffin!  Want to be a 'test subject'? 

 

[Logrinn]

Mayfly - that's an excellent idea! I'm genuinely convinced you're on to something here:

Convert your Fender Blues Jr to a professional boutique amp with Mayfly's
Fender Blues Jr Boutique Kit
-
only $199.00​

 

[ragamuffin]

Cool idea! BillMAudio.com sells some diy upgrades for the Blues Junior, but I don't think they do a full "unboarding"