Custom amp. Reduce gain
Hi,
I recently got my hands on this beautiful little custom amp based on a 1957 5F1 champ. It sounds great at high volume, but the problem is that I need an anti-feedback pedal to be able to crank the volume. Without it, I only get up to 5.
Input #2 is low and sounds best for the harmonica. I use an JT30 mic.
What do you recommend to lower the gain so I can use the amp without a pedal?
The 3 tubes are 12AX7, 6V6GT, 5Y3GT.
Thanks David.
It's a custom JT-30 with a 99H86 CR element. Not the crystal element.
I will get those tubes and try them out. I will let you know which one I prefer.
Thanks for the feedback, really appreciated.
-Gabriel
Do you have a store to recommend for buying tubes? I am guessing it would be best to get the NOS ones? I live in SoCal.
Thanks
Gabriel
Okay, good to hear about the mic Gabriel. I personally like to get vintage tubes from eBay, but I use vintage gear. For a new amp, JJ's would be fine https://tubedepot.com/t/tubes/preamp-tubes
David, what are your favorite brands of vintage tubes?
GE, RCA, Tung-Sol, Slyvania, and Ken-Rad have all served me well
I got the 3 tubes today and played around.
12AT7 sounds great. I was able to crank the volume to 7/12 standing right beside the amp. The sound still has that nice crushiness. Very good!
Next I tried the 12AU7, and even if I was able to crank the volume even higher up to 9.5/12, it did not sound as good as with the 12AT7.
Finally, the 12AY7 was the clear winner here. I love how it has as great of a sound as the 12AT7, but I could make it sound even better because I could crank the volume up to 8.5/12 ! Nice chrushy sound and I could cup the mic without feedback.
Thanks again David for your help.
Fantastic... thanks for checking in and letting us know.
Hello gabbeauchamp. I'll jump in here, since Skip answers more of the repair side of things. The 12AX7 is the one to mess with. I recommend you purchase three tubes... 12AT7, 12AY7, and 12AU7. These are all common tubes, and ones you will use and sub often through your life as a musician, so it's worth the purchase. Try them in that order and see what you think. I'm guessing you'll like the AY the most. Report back with your preference.
P.S., the crystal element in a JT30 is not as distorted as a Shure CM or CR. In my experience, most players prefer the CM or CR with Fender-style amps. Something to keep in mind for your next purchase.