投稿日: 10月 18, 2012 カテゴリー: Modding
This is going to make me a liar, but this post is about all successful mods I’ve done in the last week or so:
- Valbee Diodes Disconnect: Before I even bough a Valbee tube amp, an electronic engineer in Sweden told me about all sorts of simple mods you can make to a Valbee. The first one is cutting the clipping diodes in the boost stage. Why do this? To get more natural tube distortion, which is the point of this amp anyway. The clipping diodes are a pair of diodes that clip the top and bottom of the wave form, creating what guitarists call hard “distortion” rather than mild “overdrive.” By now, I know enough about electronics to recognize the two diodes on the board, but I didn’t cut them. I actually quite liked the sound of the distortion, so I decided to use the soldering iron to remove them, just in case it turned out that I preferred that sound. This was easier said than done since the diodes were very close. I couldn’t get a grip on them with any of my tools until I tried the Total Recall subcutaneous tracker removal device. Now I can get a much fatter clean sound with the Boost engaged! Turning the gain up past 2 o’clock produces adequate sustain and fuzz, but the real fun begins when you put a compressor, booster, or overdrive in front of the amp.
- Little Lanilei Speaker Swap: Kalle, the Swedish engineer, told me that the Valbee’s 4ohm speaker is mismatched to the amp, and that it will work find driving and 8ohm speaker. The Little Lanilei‘s 6″ speaker is rated 8ohms, and sounds brilliant. Fortunately, it fit perfectly into the Valbee’s speaker baffle. Now the shadowy, artificial sounding low-end is gone. Unfortunately, the amp is louder and heavier, too. I’m seriously considering leaving it in there permanently. While I was at it, I removed the cheesy white Ibanez logo from the Valbee’s speaker grille.
- Valbee Tube Rolling: The Valbee I got is a very noisy amp. I replaced the cheap Chinese 6L6GC with a NOS Russian military 6Π3C-E (6P3S-E), which improved the overall tone, but didn’t eliminate the buzz. So the noise could be because the amp isn’t properly grounded, or it needs new capacitors on the power supply. I also replaced the EH 12AX7 with my lucky JAN 6072A (12AY7) at the same time I removed the clipping diodes. Not very scientific, but I’m sure this will create an improvement. Still, I want to try swapping it with lower and higher gain preamp tubes I have on hand.
- Buffer/Battery Swap: Last year I custom ordered a limited edition red Tone Press from Barber Electronics with a B-Buff installed. This converted the true-bypass pedal into a buffered pedal to buffer the guitar’s signal even when off. The B-Buff can also boost the signal to increase sensitivity in the other pedals. Unfortunately, the buffer circuit takes up the space for the battery, meaning you need an AC adapter. Not being able to use the Tone Press as a stand-alone pedal is inconvenient. So I sent an email to David Barber asking for instructions on how to remove it. Actually, I described my procedure to him and asked him to verify it. He kindly pointed out my mistake of connecting the black wire from the battery terminal to the output instead of the input. Thanks to him, the operation was a success. I used a piece of a paper-clip to connect the input to the DPDT switch, and a cutter on the double-sided tape holding the B-Buff board in place.
- Output Buffer Transplant: Not wanting to wasted the cool buffer circuite I removed from the Tone Press, I decided to install it in my Budwah as an output buffer! My Buddah wah is the older version in the purple Dunlop base, so there was plenty of room. After searching a bit, I found detailed instructions for installing an output buffer in a Budwah at Foxrox Electronics. (BTW, this guy is HEAVY — he’s the the real deal.) Again, easier said than done. Desoldering and resoldering the components to the pot and the board wasn’t easy for me. If I had read carefully, I would have noticed that the FWR buffer, Blue wire=Output and white wire=input. This is the reverse for the B-Buff, so initially I just heard hum when I switch on the pedal! Also, the input, output and ground leads were too short, so I had to solder on extensions using tape as insulation. It looks terrible, but it works. Now I can get up to a 20db boost when I stop on my Budwah. This was my favorite feature of the Behringer Hellbabe wah.
Since I haven’t made window baffles for my play room, I hope to test all these mods tomorrow night in a rehearsal studio.