From: "Don D." Date: Wed, 07 Jan 1998 23:40:12 -0800 Subject: Re: (Kein "Betreff") RI Bassman suggestions
> From: Thomas.Steinbe~-online.de (Thomas Steinberg) > Date: Wed, 07 Jan 1998 22:25:01 +0100 > Subject: (Kein "Betreff") > > Anyone has a good sugestion (i.e. fatter sound, less feedback) for a > setting when using a BM Ri and a Shure Green Bullet? I replaced the > solid state rectifier with a tube and maybay I´ll change the > preamp-tubes too. Nevertheless - when I think, I have found the right > way I´ll be not so sure after a while. It´s neither the problem of > holding harp and mic tight nor making a good acoustic sound. > > Thanks for hints > Thomas
Changing the rectifier is a good move and what kind of tube you switched to matters also. You can try either a 5AR4/GZ34 or a 5U4 rectifier. The 5U4 will give you a little more compression (ie:distortion or overdrive) than a 5AR4/GZ34 at lower volume. You can try a 5Y3 which will give you even more compression but the use of a 5Y3 is a bit iffy in a RI Bassman, the tube will probably not last long. Switching rectifier tubes may alter the bias to the power tubes and it would be a good idea to have the bias checked by an amp tech. Actually a bias adjustment could help in making the amp sound beter anyway. Switching the pre-amp tubes will help also. Try 12AY7's, first switch the first gain stage tube (the one all the way to the right looking from rear of amp), if that doesn't reduce gain enough then also switch the next tube to the left, you can even try switching the phase inverter tube (the pre-amp tube next to the power tubes) also. You can also experiment with 12AU7's or 12AT7's or a combination of all three types to find what suits you best. There are quite a few RI Bassman owners here on harp-l whom I'm sure will share their favorite tube set ups with you. You can try patching the two channels also and playing with the two volume controls to find a setting that will help fatten the sound. That subject was just recently discussed here a few weeks back, you can check the archives for more info.
