Grateful Dead Music Forum

Can someone explain to me in layman’s terms the purpose of a power amp when combined with a twin. There is so much written on the topic but I’m still not grasping the concept of needed a powerful amp to push speakers in a signal chain which contains a twin reverb amp. How does the twin work when combined with the power amp versus when it powers the cabinet direct? It just seems like a twin is the last kid of amp that needs to be boosted by a power amp.

I’ve got a 73 twin and a birch ply cab with two D120f’s which is heavenly, but perhaps just a bit to soft and clean without an OD pedal in the signal chain.

There is a vintage BGW 250d power amp on our local craigslist for $160. Actually the guy has two of them. I googled this amp and Garcia in the same search phrase and it brought me right back to a thread on RUKIND from just a few days ago with JamminJohhny playing some great stuff.

I’m also seriously eyeing the AXE FX 2 and but just love my new birch cab which I’ve only had for a couple of months and a few gigs so I thought using a poweramp and my cab with the AXEFX2 down the road might be a cool looking and sounding rig for smaller venues. Any more thoughts on going this route would be appreciated. My sense is you really want to ditch the amp/cab combo and go with the full range speaker which would make getting his particular power amp perhaps redundant in 3-6 months time, assuming I bite the bullet and go digital.

Peace

James

Fender Twin Reverbs have both a preamp and poweramp inside.

Folks customzie their Twins to send the preamp signal OUT before the poweramp and decommision the poweramp section.

Objectives of the external poweramp:
1) remove tonal changes from poweramp tubes
2) get louder before distorting
3) claim that they sound the same at low as high volumes *
( * I do not believe that as the equal loudness / Feltcher - Munson curve says differently )

I do live sound too and do yourself a huge favor: if you go for a Axe or 11r or POD get powered speaker. Look at the JBL PRX series (with Crown poweramps on board) or QSC or the new Mackie DLM series which I'm currently drooling over and pondering a major overhaul of my rig to replace all current with those!

Thanks

This is an excellent answer to a simple yet seemingly very complex question (see post on can anybody really nail this tone). I think I'm totally on board with your advice. Just go digital as the technology is there now and in the long run much cheaper for those folks who have not yet built up a big (or multiple) ri(s).

One of the best answers I've read on a gear forum in a long time. I think the key to the tube/ preamp/ speaker signal chain is having space to have volume, and in many gigs it's just not possible to push our gear to what it's designed for. With an Axe FX/ 11r or POD this can be achieved easily.


Peace,

James