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Grateful Dead Music Forum

A place to talk about the music of the Grateful Dead 

 #49474  by clifton hanger
 Sun Sep 14, 2008 11:18 pm
Hi folks. first post here and i am so glad to have found this site. for you guys using the separate preamp and then power amp config (mcintosh, qsc, etc), do you send a stereo signal out of the preamp to the two channels of your power amp? or do you send the signal out of the mono out to one side of the power amp. I am trying to determine how jerry did it to drive the speakers in a similar fashion. thanks.

 #49476  by playingdead
 Mon Sep 15, 2008 5:48 am
Since my cabinet is mono, I fed a mono signal from the preamp to my power amp and bridged it mono. That was when I was using a Trio with a Crown 402 power amp.

Now, I run a two channel AR Focus power section, and use one channel for the feed from my Egnater preamp, and the second channel I use for the wet output on my Real Tube Reverb. But I'm still running one output from the power amp to my mono cabinet.

I suppose, if you were using a 2X12 cabinet, you could feed each speaker from a separate channel of the power amp, but I'm not sure there's any benefit from that unless you want to run some of your delay or modulation effects in stereo. But then you'd want to mike both speakers through the PA, too.

 #49485  by tigerstrat
 Mon Sep 15, 2008 9:21 am
If you are asking how Garcia ran his rig, it was never stereo preamp output. He ran mono out to a Mac 2300 in bridged mono mode (approx 600w), into 3-4 (or 2 in 1991) JBL E-120's. During the 73-74 Wall of Sound era it was at least two 2300's, (maybe more outside his rack) powering 18-20 JBL D-120's.

 #49487  by clifton hanger
 Mon Sep 15, 2008 9:33 am
thanks guys. it looks like garcia was loading a total of 900+ watts of jbl with 600 watts of power. makes since to avoid speaker breakup.. is there anything i should take into consideration if I was to go and buy a crown or qsc with 600 watts bridged mono? besides it not being or sounding like a mcintosh. Has anyone had good results with cheaper power amps? thanks again for the help.

 #49493  by KCJones
 Mon Sep 15, 2008 10:44 am
IMHO good ole USA made Carvin power amps are by far the best value going. I have not heard any "top" line power amp sound any better. I have the DCM2500 and use it as my PA Mains amp, but also use it with a preamp for my bass rig. It is a vey clean low noise/distortion, very reliable amp easlity down to 2 ohms. I also have the DCM150 for my studio monitors.

http://www.carvinguitars.com/poweramps/

 #49496  by tigerstrat
 Mon Sep 15, 2008 11:06 am
A solidstate power amp shouldn't sound "like" anything, imho. Anything with a decent slew rate should sound the same as everything else. I use one side of a Yorkville Beta 400, pumping 250w @ 8ohm into a single 300w E120.

 #49501  by playingdead
 Mon Sep 15, 2008 12:01 pm
I bought a new Crown XLS 402 amp -- $350 or so -- which gave me 900 watts bridged mono. It sounded fine and had tons of headroom.

But then I heard about these Acoustic Image Class D amps, which give huge power in a tiny package, so I am using just the power section of that, which is 800 watts. It weighs six pounds. It also sounds a bit warmer than the Crown. I have the Focus 2R, it also has two preamp channels with digital effects, which I don't use, but could be used as a backup preamp if my rack should go down. And, it sounds excellent as a small self-contained PA, particularly with an acoustic guitar and a vocal mic.

So, while solid state is solid state, there are tonal differences. I'm sure a McIntosh 2300 has its own particular sound, if you are playing at home and don't mind toting around 150 pounds of amp to gigs.

 #49508  by clifton hanger
 Mon Sep 15, 2008 12:53 pm
thanks guys. playingdead, great tunes and tone. how do you like the Egnater vs the groove tube trio? I have been looking into these module products i.e. Egnater or randall but dont need 4 preamps, even though it would be cool.

And while were talking about Carvin, they now sell guitars with the graphtech ghost system (piezo synth), coil tapping mags, and unity gain buffer. throw in some super 2s and your getting close to a bolt. for around 1400. you can get a killer jerry tone from the buffer and blended piezo tone. just an fyi.

 #49528  by playingdead
 Mon Sep 15, 2008 5:07 pm
I really, really like the Egnater ... it's definitely a better choice than the Randall, handmade, better components and better overall tone.

The Trio is nice -- I still have mine although I am thinking of letting it go -- but the Egnater is much more versatile, and I like being able to dial in some extra gain on the clean modules, you can't get any dirt overdrive at all on a Trio's Clean channel.

I have the M4 but Egnater is just now coming out with the E2, which will be a one-space rack unit that will hold two modules. I have to warn you, those little modules are pretty addictive, I have the Twin/Deluxe, the Vox, the Bassman, the SL2 (Marshall) and the EG-5 (high-gain/Soldano).

I am trying some different tubes in the chassis and the modules now, sounds great.

Carvin guitar sounds interesting; most folks will tell you that Jerry never had a piezo in the Bolt, it was just running the Trio direct to the soundboard that gave that bright, trebly tone. But a piezo would probably sound similar.
 #78494  by vinyldude61
 Thu Apr 22, 2010 5:24 pm
no, no, i'm pretty sure that garcia only i had one power amp in the wall of sound, same as weir. that single 2300 was throwing 600 watts into twenty twelve-inch (i think) drivers, two per cabinet. weir had the same power amp/speaker configuration. phil, on the other hand, had 4 2300's for a total of 2400 watts driving 36 fifteen-inch drivers, one per cabinet, stacked in two columns of 18 cabinets each.

the bulk of the power in the wall of sound (nearly half of it, maybe?) was devoted to the vocal clusters, as power use is much more efficient with electric guitar than with voice - and bass is somewhere in the middle, hence phil needing four power amps, whereas garcia and weir only needed one to play plenty loud and clear.

i ask you this, though: does anyone know how soundboard recordings were made with the wall of sound? since there was no mixing board in that PA, how were board recordings made?

Re:

 #78498  by myoung6923
 Thu Apr 22, 2010 6:34 pm
clifton hanger wrote:thanks guys. it looks like garcia was loading a total of 900+ watts of jbl with 600 watts of power. makes since to avoid speaker breakup.. is there anything i should take into consideration if I was to go and buy a crown or qsc with 600 watts bridged mono? besides it not being or sounding like a mcintosh. Has anyone had good results with cheaper power amps? thanks again for the help.
I tried a QSC for a while - I think it was putting out 700 Watts - into 2 jbl e120's. It was brutally clean - at ANY volume. You just COULDN'T get it to break up - no dirt at all unless the speakers were freaking out (which you DON'T want). I haven't tried the mac route but I think if you get a lower wattage one - maybe around 100 watts - you can get that dirt but you'll still be pushing it hard to get it.

I went back to just using the Twin's own power section - it has all the power that I need for the stages that we play on - and we play on some big ones in big rooms.
 #78500  by waldo041
 Thu Apr 22, 2010 6:37 pm
vinyldude61 wrote:i ask you this, though: does anyone know how soundboard recordings were made with the wall of sound? since there was no mixing board in that PA, how were board recordings made?
individual microphones ran to a board and reels in a room backstage. betty cantor and bob matthews usually at the controls.

peace,
waldo
 #79104  by 540EYE
 Sun May 02, 2010 9:21 am
Hi,
Just finished reworking a Mc2105 into a rack mounted unit. Glass was busted and got it pretty reasonable. I use a home made "Y" from mono pre out into the Mac's L+R channelsEach channel runs a 2 x 12" cab with (2) E-120's @ 8 ohms / cab. Also running an outboard Mac P-438 Power Guard that I scored from Brad. Depending on the mood, I run either an Intersound IVP or a GT Trio. Right now, I'm kinda diggin' the IVP. It does "Jer" extremely well, although it is more associated with Weir. Very tweakable, crisp and QUIET.
There is a switch on the back of the 2105 labeled "Direct" or "Normal".....haven't figured out what the difference is. Can anyone shed some light on this??

BTW, I love this place!!
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