Scouring Musician's Friend's site, i stumbled on a bunch of neat amps that are USED. Among them was the Epiphone Blues Custom 30. One thing that intrigued me was the use of a tube rectifier - not always seen on modern tube amps, its mostly considered by engineers to make amps unreliable, one reason why most tube amps are built with solidstate rectifiers. Also another consideration for NOT using them is the increase in power that an amp can generate, which in these days, something that majority of users seem to prefer. Or something that amplifier manufacturers seem to perceive is where the market is. People want more power, lets make one that can do give them that. Tube rectifiers eliminated, amps can push farther out in its power handling.
Tube rectifiers do change the way the amp handles its power, and consequently affect the tone it produces. Theres always what is called a "sag" when teh amp is pushed. In a nutshell, when an amp is turned up as in guitar amps, playing notes seem to produce a compression-like effect, sustain on a note a lot longer. The other effect is that picking isnt as respinsive as with a solidstate rectifier. Jazz and metal players, or anymusician who needs to be able to articulate 32nd or even 64th notes will find this unuseful. However, if you play blues, or use less notes in phrasing, this can manifest a unique, and in my opinion, a more soulful tone.
That being said, ive personally heard the difference, using an old modified Bell & howell 15W 6V6 amp turned up. Sweet, unmistakable bluesy tone. Initially, ive always been after a Fender Prosonic, a discontinued tube amp made in the mid 90s. Its unique feature - a switch to use solidstate rectifier OR a tube rectifier. Something that Mesa amps have used in a while now. Though it doesnt have a solidstate rectifier switch, when i saw the blues custom 30 being sold used in working condition at a ridiculously low price (after a coupon added), i decided to just go for it. I wasn't disappointed.
I decide to keep the speakers stock (2 12" 70W Lady Luck speakers made by eminence). The tubes though, i pulled and replaced with old stock i keep in my collection. Sylvania and Raytheon 6L6GC tubes, mullards for the V1 and V2 preamp section, a US RCA in the phase inverter, and telefunken tubes in the reverb section. The footswitch i ordered separate, but came in quick (though not a sponsor, Sweetwater gets a big thumbs up!)
After about 2 weeks i decided to dive into the mods, only after i got some problems with the volume control of CHannel1. It started to go in and out. After some diagnostics and poking around (methodically done with safety precautions of course), i found the issue to be a loose lug, most likely having a bad solder. After fixing it and the chassi still out of the cabinet, i decided to cut one leg off of a couple of capacitors as suggested in the Epiphone forums. Sure enough the noticeably treble-y stock sound of the BC30 tamed a bit, but the most noticeable imrpovement in tone was paralleling a 5.6K/2W resistor on R15. The overdrive on Channel 2 is more distinct, clearer, brighter, less muddy at lower drive settings. It has a perceived increase in loudness as well.
Though the stock sound of the BC30 is actually good on its own, these mods improved its tone. To me, options are always a good thing. To offer that in this unit, im installing small switches. Im more likely to put the switches on the back to keep the front panel clean.
Bottmline, i enjoying this amp a lot! right now im tube rolling with the tube rectifiers. From what the circuit calls for (5ar4), to 5U4, 5V4, and a solidstate rectifier. During research and comparing their datat sheets, im very well aware that this can wreak havoc, even damage the amp. This definitely is NOT for the faint of heart, or those who prefer not to have that scenario even taking place. SO i do not suggest what im doing for anyone to do. This is my own experiment, and however foolish or misguided it may seem, its not without proper and more than sufficient knowledge and research. I am prepared to suffer consequences in pursuit of sonic research.
Plus without being brave or foolish, no one would discover other lands, no one would have rock n roll. If Jimmy Page or Eric Clapton or Jeff Beck or Jimi Hendrix did not turn their plexis and AC30s all the way up, they wouldnt have made those sounds we now consider legendary, and wouldnt have spawned what we know of now as ROCK MUSIC. Of course, it made their ears ring permanently, and amps blew and had to keep going back to repairs, but such little sacrifices are worth it!
For the BC30, its a gem of an amp, that im amazed at how good the sound is with very little futzing around. something i cant say about my valveking 112. Whatever the case may be, this amp is a keeper!
The way i see it: play safe, or play loud, just play!!!