F2B power amp impedance matching

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Author Message lprainard New Username: lprainard Post Number: 1 Registered: 7-2012 Posted on Thursday, July 05, 2012 - 3:19 pm:    I just got my hand on a used F2B. I would like to incorporate it into my bass rig but I am running into the high output ohms into low input issue. The only power amp I have at the moment is a Pevey IPR 1600 with a input impedance of 7.5 ohms unbalanced and 15 ohms balanced. The Alembic site says anything <10ohms>200ohms is ideal. If I run the unbalanced line out into the balanced xlr (ground and - tied together) will that get me to the 15ohm balanced rating for the amp? Is that still way to low for the F2B? could running into the 7.5 or 15ohm input cause any harm (other than sonic performance) Is the mismatch a fidelity issue or simply a loss of db? A few people have suggested a non true bypass fx pedal inline as a cheap buffer. Any thoughts on that? edwin Senior Member Username: edwin Post Number: 1215 Registered: 5-2002 Posted on Thursday, July 05, 2012 - 7:51 pm:    I suggest you just try it and see what happens. The F2B has plenty of level and I doubt that you'd run into a tonal problem due to impedance issues. I've run mine into lots of different power amps, from McIntosh from the mid 60s to Crown and QSC from the last 5 years. No problems with any of them. Impedance issues in this situation are not like dealing with impedance issues in amp to speaker situations. I do believe that this very issue has been addressed by Ron recently, although I'm not sure where the thread is. lprainard New Username: lprainard Post Number: 2 Registered: 7-2012 Posted on Thursday, July 05, 2012 - 11:20 pm:    Thanks. I am sorry for bringing this topic up again but it seems like the other threads quickly headed into talk of modifying the preamp. I just realized that I did not put a k after any of the ohm values. Also "The Alembic site says anything <10kohms is not good. Other posts say >200k ohms is idea" is what I meant to say. That's what I get for writing this at work (Message edited by lprainard on July 05, 2012) edwin Senior Member Username: edwin Post Number: 1217 Registered: 5-2002 Posted on Monday, July 09, 2012 - 2:47 pm:    So, did you fire it up and see how it went? slawie Senior Member Username: slawie Post Number: 417 Registered: 8-2002 Posted on Wednesday, July 11, 2012 - 4:29 pm:    This was discussed here with input from Ron. http://alembic.com/club/messages/394/81863.html Slawie