twanger

The use of laminates (plywood) has a very, very long history. Laminates are layers of veneer glued together crossing the grain of each layer. this technique has been found on wooden items removed from Egyptian tombs. Crossing the grain of each layer of veneer imparts a deal of strength and durability to the finished piece. Using veneers allows the more beautiful pieces of wood to be used for far more items. Wood with curly, swirly, interlaced grain structures tend to be very unstable and prone to cracking. When shaved into thin veneers and laminated onto a more plain or straight-grained piece of wood allows the veneer to retain it's beauty without cracking and makes an otherwise common piece much more beautiful. For you fans of the Les Paul models made by Gibson and Epiphone and many other companies, you must realize that the beautiful maple face on those guitars is laminated on top of the mahogany body. If you look at the Epiphone Prophecy series you will see that all models have a laminated face. this is a common practice on many high end guitars and those of lesser stature and quality. A veneer is an inexpensive piece of beauty that does wonders for sales of otherwise dull and boring instruments. My first encounter with a plywood solid body guitar was when a friend brought over his Memphis guitar for repair. It was pretty, lightweight and inexpensive. It had humbuckers mounted on it and I marveled at how good it sounded. I was somewhat taken aback when I opened it up and saw the multiple layers of the body. I couldn't wrap my mind around the use of plywood and more to the point the excellent sound that came from the guitar both unplugged and plugged in. Once I got past my cork-sniffing snooty attitude about plywood I was able to not only enjoy but spend my hard-earned money on laminate body and even laminate neck guitars. This technique of instrument construction is used on many instruments like drums, violins/violas/cellos/bass viols, pianos, etc.. What it really comes down to is the choice of materials (wood and glue) and the techniques employed to make the laminate. would you be surprised to learn that Gibson's Kalamazoo brand of guitars were made with what is called today, MDF? The original Danelectro and Silvertone guitars were made with a Formica top. Fender tried laminated wood on "Wildwood"(?) series, Many thru-neck guitars and basses from many manufacturers are made up of different species of wood laminated together. In the end the material used to make an instrument is considered to be good if provides 2 characteristics: 1) good sound and... 2) strength/durability. Plywood has more than proven itself as an acceptable and good material.

Good stuff guitslinger! So, how's channel 2 sounding? I'm quite happy with how channel 1 sounds on my amp. I now would like to do something about channel2. The drive is just "harsh" is the best way I can describe it. It's much better than it used to be but it still needs to be tamed. I'll give the 5881s a try as your description sounds intriguing.

Switching the standby down to the "STANDBY" position "blocks the sound". This should be standard practice on any tube amp. When done playing switch to standby first then turn off the power. This way the switch will be in "STANDBY" when you turn it on. Going to a solid state rectifier will possibly boost voltage a bit (this is NO problem for the amp). A solid state rectifier will NOT affect the sound since the rectifier is ONLY concerned with the power supply. Tube rectifiers DO affect the sound sometimes. This is typically referred to as "sag". This typically happens (NOT always) when the amp is turned up and the player hits a power chord or a note on the low E and/or A strings. It can also happen if the player is using a pedal that boosts or overdrives the amp. This causes a rapid power draw which is heard as a sagging sound. Some players like this sag and others do not. My BC 30 still has the tube rectifier. It sags. I like it. My Mesa Boogie combo has a solid state rectifier. It doesn't sag. I like it. Both sound great!

Earlier in the thread someone mentioned cutting the caps one at a time and then listening to the amp after each cap was cut. Since this may be a little new to you it might be a good procedure to follow. That way you're less likely to "snip a cap too far". If you do it this way I would follow papamidnite's order of making the cut(s). Update on my BC 30 changes: Papamidnite had mentioned THD Yellowjackets so I decided to find out what these were. They are a tube converter that let's you use EL84 tubes instead of the 6L6 power tubes. They drop the output of the amp to just over half. They also get overdriven easier. They do such a great job of getting overdriven earlier that I removed the Celestions and re-installed the Lady Lucks. This way I get more tube overdrive and less speaker break-up...a MUCH better sound! Not only that, the Lady Lucks have reached that point where they are fully broken in now and I'm really liking them. Now I'm on to the reverb. Earlier I put a 12AT7 in the reverb drive to tame it. It tamed it alright but not enough for my tastes. I just put another 12AT7 on the reverb's output and it gave it a much smoother sound. Very mellow. The next thing to reign in is the long tail on the reverb. It's 3+ seconds long which is too long for me. There's also a "bump" in the reverb's sound that's just slightly louder than the original note. It wouldn't be so bad but there's this slight delay before the bump. If I made a simple graphic representation of it, it would look about like this: ___--________ So I'm kicking around a couple of ideas. First is the reverb transformer. Next is perhaps one of the caps from c20 to c23 should be changed as one or more of these may be the culprit adding in the delay before the bump. Maybe replacing r25 with a pot may work. I'm going to look at some other amps schematics to compare reverb circuits and see if I can come up with a solution or at least a working idea. Other than that I'm extremely happy with the BC 30. It sounds great.

Sorry! I didn't even think to record the changes. I will say that cutting the caps will reduce the brightness adequately to allow the use of the treble control on the amp's eq as well as the treble control on your instrument. If you don't like the idea of cutting the caps you could simply desolder one or both legs of each of the caps and remove them from the circuit board. The only thing to consider here is that you would have to remove the circuit board from the amp's chassis to accomplish this.

HOLY Flurkin' SCHNIT! Oops! Can I say that here?!? Oh well... I already did. Yesterday the Groove Tubes came so I knew I would be spending this a.m. working on the amp. Here's how it went down... 1) I pulled the original Sovtek 6L6 tubes and replaced them with a matched duet of GT 6L6 tubes that were rated 3 (blue) which is low rating. I selected this rating in the hope that I would get an earlier breakup and I did. 2) I pulled the phase inverter tube (the 12at7 I swapped for last time) with a GT SAP-AT7-MPI (a 12at7 with matched output on each half of the tube). I did this with the idea that each 6L6 would receive an equivalent signal level so the overdrive/distortion of the drive channel wouldn't be so "jagged" sounding. The first 12at7 I put in there cleared up a great deal of the roughness of the drive channel but it was still "jagged" but much improved over the original EH 12ax7 that was in there. 3) I didn't put the back on, just turned it around and plugged it in to see if there would be any difference. WOW! HFS! What a difference! I could tell I was getting my full 15/30 watts worth! I also got the all the brightness that others have spoke of. The decision was made to snip the C3, C5, & C6 caps. Before I decided to do the surgery I thought I would give the Celestions another spin. A clear difference over the Lady Lucks and a difference I regard as an improvement. I figured that I'm this far along and the decision to snip the caps had already been made so I decided to go ahead and change the speakers. While I was at it I figured that I would go ahead and take that 12at7 that I pulled from the PI position and pt it into the reverb drive position. 4) I got it all done and just finished playing with it...INCREDIBLE! This thing now barks with authority! It's very touch sensitive now and not nearly so bright.. I can actually use my treble controls not only on the amp but on my guitars also. The Celestions sound even better in the semi-open back BC30 cab than they did in 4x12 cabinet. The clean channel now has a killer tone and incredibly smooth break-up when you get on it. The drive channel is now very usable with plenty of bark and a smoother growl rather than that "jagged" sounding distortion. Oh yeah! This baby's a keeper now! A big thanks to Papa Midnite, cgil, stevencg2, sprinter and everyone else who contributed to this thread! As an added note, there's a place that's new to me called Warehouse Guitar Speakers (WGS) that are offering what's billed as a replacement for the Celestion G12-65 speaker at a reasonable price ($65), here's a link: http://www.warehousespeakers.com/ Here's another placed that offers some interesting alternatives...Weber Speakers: https://taweber.powweb.com/weber/

Here's my updates on improving my BC30: 1) No circuit mods yet as described earlier in this thread. 2) Changed some tubes as follows (I had to order GT through a catalogue - Woodwind & Brasswind -GT Gold tubes are currently 20% off) While waiting for the GTs I nabbed some Ruby/JJ 12ax7 for the signal gain and a 12at7 for the phase inverter position. Wow! 3) Found a Fender 4x12 on the local Craigslist cheap (pardon the gloat - $90) It had a driver with an open coil. I figured it would be loaded with the regular Fender fare but found all drivers were Celestion G12-65 15 Ohm. The tube change for the phase inverter position to a 12at7 really smoothed out that lame distortion and gave me a little less headroom on the clean channel with a much smoother breakup as I drove it harder. The Ruby/JJ 12ax7s gave me "softer" tone with less treble. I'm hoping that when the GTs arrive that the tone will improve further. Those will be matched 6L6s (with the low output rating) along with the SAG-at7-MPI for the phase inverter (the current 12at7 will get moved to the reverb drive position) and a couple of the 12ax7-C (from China) to experiment with in the signal positions. The Celestions were somewhat of a surprise. They sounded pretty much just like the stock Lady Luck drivers in the BC30 with 2 notable differences...they broke up earlier and they had more bottom end than the Lady Lucks. I'm still trying to sort out if these differences are due to the Lady Lucks being newer and still needing to be fully broken in (the Celestions are already well broken in) and then the extended bottom being due to the 4x12 cabinet. I figure I'll wait a while (a month or so) before I start swapping out drivers to the give the Lady Lucks some more time on the break-in process. After the GTs arrive and I get them installed and see how they play I'll decide whether or not to mod the circuit. I'm likin' this more all the time!

Here's an interesting bit...compare the following schematics.... BC30 - http://www.ppwatt.com/files/ppwatt/EPIPHONE_BLUES_CUSTOM_30_SCHEMATIC_VER01_DPPT.pdf SoCal 50 - http://i28.tinypic.com/19ms0p.jpg Other than transformers and output power tubes I don't see much difference.