|
Author
|
Topic: preamp tubes in a champ
|
Walter Killam
Member From: Nebraska, USA
|
posted 14 August 2006 06:52 AM
profile
I play an old Silver Face Champ for low volume rehearsals & sitting at home sometimes, yesterday I replaced the preamp tube with an old Sylvania 12AU7A I salvaged out of an old HiFi amp & I have to say WOW that cleaned up/warmed the amp so well it's amazing! I have clean gain and crisp volume all the way up the dial. I'm thinking about trying some other tubes now just to hear the difference. Has anyone had any experience with 12AT7XX's on the preamp?------------------
Magnum SD10, Ultralinear Twin, who could ask for anything more!
|
Karlis Abolins
Member From: Burien, WA, USA
|
posted 14 August 2006 09:26 AM
profile
I have an amp which is virtually identical to the champ (because I made it so). I experimented with the preamp tubes and ended up with a 12AT7. The 12AU7 is clean to the top as you relate. The 12AX7 breaks up too early. The 12AT7 breaks up near the end. I play blues and sacred steel through the amp so a little distortion adds "color" to my sound. Karlis |
Thom Ferman
Member From: Las Vegas, NV, USA
|
posted 14 August 2006 10:10 AM
profile
This is an interesting thread to me. I just resurrected a '74 SF Champ that I got on eBay packaged with an old Fender Deluxe 6. I'd replaced the can type filter cap. with one from Ted Weber and put in JJ 12AX7A and 6V6 tubes. The old GE 5Y3 that was in there worked fine. At any rate, last rehearsal I mic'd the Champ with an SM57 and ran it up to 9 on volume, treble and bass. With my Gretsch guitar, that little amp sounded so sweet through the PA I'm thinking of abandoning the monster Vibrasonic I'm lugging around. It was a very "honest" uncolored yet rich sound, all out of that little stock 8" speaker. I'll be trying the Fender steel through it next. Perfect for the Rockabilly/early '50s country sound I was looking for. I want to try the preamp tube swap next for variation. I'd love to hear anybody else's experience in mic'ing up a Champ for gigging.
Thom |
Dave Mudgett
Member From: Central Pennsylvania, USA
|
posted 14 August 2006 10:56 AM
profile
I use a silverface Vibrochamp from time to time, both for guitar and steel - mostly for low-volume rehearsals or even acoustic gigs. The bottom end isn't there, but sometimes that's what's required.I've tried every type of preamp tube I could get my hands on in various types of Champs. To my ears, a Champ is probably the most direct-sounding tube amp ever made. One hears the sound of the individual tubes, with only minimal tone controls or other coloration. You may find this mini-preamp gain chart useful: http://steelguitarforum.com/Forum11/HTML/006922.html Of course, these are nominal gains, and give a rough idea of how the tube will react. I often like the industrial tube 5751, which has gain pretty close to a 12AT7 - but I usually prefer the 5751. I'm not sure it's just the gain difference. My general opinion is that it's hard to predict what tube will sound good in an amp based on type and brand. I have a box of various types and brands that I have accumulated over the years, and just try different ones in an amp until I like the sound. Sometimes I'm very surprised to find out what really works in an amp, and may change my mind, based on what I'm trying to use the amp for. |
Jim Sliff
Member From: Hermosa Beach California, USA
|
posted 14 August 2006 07:33 PM
profile
Generally, a 5751 is a much better choice...or a 12AU7. he 12AT7 is a good driver tube, but usually a harsh sounding audio tube. That's one reason you never see it in the audio path of guitar amps - it'll be a phase inverter or some other non-audio use. |
The Steel Guitar Forum
