point to point Blues Junior??

[Groover]

I am curious whether anyone on this forum used a Blues Junior to build a point-to-point, turret board, or eyelet board amp, and if so how it came out.

[Chuck H]

This may or may not interest you. It's not excatly a direct answer to your Q, but...

I've had the opportunity to work on revoicing of an import knockoff of what is basically the Blues Junior schem using 6L6 tubes. IMHO the BJ schem is a pretty solid platform for a build. Better than many common classics. One standard ommission from the schem would be the 1500pf bleeder cap at the end of the preamp. It sounds like crap and good layout negates it's neccesity. That said...

It was my job to take this amp (the one I described above) and revoice it to maximize it's potential for both clean and overdriven tones with the intention of manufacture and marketing. I did end up with a very respectable sounding amp, but... Any amp based on this design would need to be individually voiced. I did a TON of revoicing to this amp. But I do think the basic design is a really solid platform. This was a PCB amp. Which is the reason I had to stick with the BJ schem and really only perform component value changes.

I think a PTP version of this amp could be really great. You'd have to come up with your own layout and ground scheme that differes from the PCB enough to accomodate eyelet board or PTP construction. If do searches here you can find a ton of good info on layout and ground scheme design.

I, for one, think the basic BJ design is a real winner that could be a platform for many great amps if it is elevated beyond the limitations of the cheapo crap the namesake amp is built with.

JM2C

Chuck

[Groover]

What is it about a given circuit topology that would make it more needful of "individual" voicing than "tried and true" designs, such as BF Fenders?

[Chuck H]

In fairness, I would probably revoice a BF Fender too. But the BJ is sort of a package amp. When/if you move to bigger tubes or a bigger speaker the design doesn't sound quite right. And what I was saying is that the topology seems good, it's a few to several component values that may need to be adjusted. I was locked into the topology by the PCB so all I did was make component value changes and I was able to make what I considered a cheap Chinese made knockoff into an amp I would actually use. Even happily. Other things that would necessitate some revoicing with a handwired design of this amp would be the fact that the original (and the clone I worked on) both use pretty cheap transformers. If your troubling to handwire something your probably going to choose better iron and that will change things such that you may want to idealize for lower sag, broader frequency response and just anything else that better trannies may change. The BJ is a pretty simple circuit so a few small changes can make a big difference. I found that the basic design can be turned into a real monster for blues or a rocker depending on component values with almost no change to the topology.

Chuck

EDIT: To answer your actual question, I think simple circuits seem more sensitive to changes in their design and therefor may need to be revoiced when other variations are present. Different speaker, trannies, filter caps, layout, etc. All things that will likely vary with individual builds and do effect tone. Especially so in simple circuits. JMHE.