Grateful Dead Music Forum

Brad Sarno posted this on Facebook, very interesting. Of course Healy's talking about Twins played at GD stage volume.

"I had a chat with Dan Healy years ago when he said that by the late 60's they had figured out that the Twin combo amp (amp head and speakers in same cabinet) ate tubes real fast. He would clean up and tweak and re-tube and bias Jerry's Twins for a tour. Jerry would love the sound for about 2 gigs and then said something went away, got dull, lost sparkle or presence or something. Dan found that the speaker vibrations shook a certain aspect of refinement of tone out of the tubes very quickly. Then they moved to where some of the Twins were amp heads only and others were speakers only. From there on out their general practice was to keep the tubes separated from the speakers. There were exceptions where Jerry would bring out a pair of JBL'd Twins for JGB shows, but pretty much they practiced keeping the tubes isolated from speaker vibration.
We should all consider this for ourselves and not only just for tube-life and tone preservation, but man, that's a heavy combo. Nobody should be lifting a JBL'd Twin, ever ever. Split 'em up. Your spine is great and strong until you blow it, and then you pay for it forever. I know."

Coincidentally, last night I sold my Blackface Pro Reverb. I’d had it for about 40 years. While it used to be my only amp, I hadn’t played it much in the last 20 years or so. It was loaded with JBL D-120s and sounded like heaven ... but picking it up was like pulling the sword out of the stone! I definitely had second thoughts about parting with it, but I now play through an amp that weighs all of 21 lbs. OTOH, my back had no regrets seeing it go.

Bill, tgo

That could explain the Gaelic Park 8/26/71 photos from behind the stage that show 3 Twins without speakers. I had just assumed it was for the sake of easier speaker replacement. (and there may have been a discussion about that here before?)

Great pics. I'm just on the other side of the fence. No tix, no $, no miracle (of course this was long before "miracle tickets", but we heard the show pretty well.

Bill, tgo

This video just popped up and is worth checking out. It’s a mod for those with combos amps that are played at higher volumes..

https://m.youtube.com/watch?v=usFGWIGJXwQ

I had a Twin with e-120s in it and i could barely move the thing. Im not very strong to begin with haha.

Thats why I had a head cab made for mine. But im using the CTP w/JG into power amp now so my life is much easier now a days. I only used my twin combo with the JBLs for a few shows, it was that heavy ! Think the last show was when MK used it in 2012. After that I had the head cab made.

Gr8fulCadi wrote: ↑Sun May 08, 2022 7:01 am This video just popped up and is worth checking out. It’s a mod for those with combos amps that are played at higher volumes..

https://m.youtube.com/watch?v=usFGWIGJXwQ

He always shares good info, huh?

That was actually my first video I watched by him and thought it was a very cool thing to share. Especially during this whole “tube craze”. I’m gonna make these for a Super Reverb and Twin Reverb.