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Author Topic: Vacuum Tubes William Hooper Phenomenal Film Handler Posts: 1879 From: Mobile, AL USA Registered: Jun 99 posted 08-04-2003 02:25 AM                        Ed may remember that I assisted in a radio station project that utilized tubes to route smoke into a newsroom board to entertain the news guy while his mike was open. Those are the best kind of tubes. We had to get a consultant who had understanding of bong technology to modify a dishwasher detergent bottle to incorporate a cigar as a smoke generator. INCREDIBLE output.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 08-04-2003 09:19 AM                        When I worked at the Grandview Drive-In in the late 1960's, we still used one of those ~1953 "turnkey" RCA sound systems to power the field speakers. I still remember some of those really hot summer nights when the plate leads to the 807 tubes in the final would catch fire (due to the deteriorating insulation). Our CO2 fire extinguisher "saved the day" on more than a few occasions.  |  IP: Logged Edward Jurich Master Film Handler Posts: 305 From: Las Vegas USA Registered: Jul 2003 posted 08-04-2003 12:22 PM                     William Hooper said... Ed may remember that I assisted in a radio station project that utilized tubes to route smoke into a newsroom board to entertain the news guy while his mike was open. That Hooper is quite the gagster, I remember when he put his best foot forward to stop a showing of "The King and I"  |  IP: Logged Andrew Duggan Expert Film Handler Posts: 127 From: Albany, NY, USA Registered: Jun 2002 posted 08-04-2003 01:14 PM                        My guitar setup is also tube driven, a 77 Music Man amp head, using 12ax7s/Preamp and EL34s/Power. It sounds somewhere between 1 and 2 million times better than my old solid state amp. Good times. (It's also heavy enough that if my stack ever feel on me during a show that I would pretty much die instantly. Nothing like living dangerously....)  |  IP: Logged Aaron Sisemore Flaming Ribs beat Reeses Peanut Butter Cups any day! Posts: 3061 From: Rockwall TX USA Registered: Sep 1999 posted 08-04-2003 05:53 PM                     quote: BIGGEST TUBE MISTAKE: I once owned 2 (TWO) McIntosh MI-200 power amps. I was 12-13 years old, and a friend of a friend of my dad gave them to me. The thing I remember most about them is the weight! I couldn't find the 8005 tubes anywhere, so they sat in the shed until we did a dump run. Recently, I found out how valuable these units are today. I have a couple of BIG tube mistakes as well (If I only known then what I know now!): -I had an EICO ST70 integrated amp (7591A outputs) that caught fire on me in 1987. Rather than repair it, I just sent it off to Goodwill. Didn't even pull the tubes -Around 1985 I had a beautiful near-mint Dynaco ST35 power amp that I traded in 1986 for a pair of 6550's (!!) and a large HAM rack that I wanted the trannies and chokes out of. ST35's are one of the most sought-after, rare Dynacos out there nowadays Sometimes I still smack my head when I think about what I had done -Aaron  |  IP: Logged William Hooper Phenomenal Film Handler Posts: 1879 From: Mobile, AL USA Registered: Jun 99 posted 08-05-2003 02:32 AM                        Ed:  |  IP: Logged Lindsay Morris Expert Film Handler Posts: 233 From: Darlington, WA, Australia Registered: Sep 2002 posted 08-05-2003 06:08 AM                     807's...a nasty surprise for the unwary are those fellas. Usual quick test was "finger on the grid" trick for a rough estimate of where the problem lay in valve amps except if they used 807's as the grid cap was not one of those but the anode instead. Can still remember the look of horror/surprise on a "smarty pants" looking over my shoulder once when I was pondering what was driving an RCA amp with 807's absolutely crackers. (noise was out of this world). Comment from smarty pants "easy things to fix these, just bung your finger on the grid and listen for the noise".. He did just that but no noise from the amp it all came from him when he hit the 807 anode cap first up seconds before I could say anything. He slunk off with my peels of laughter ringing in his ears and then the boss wanted to know what all the noise was about. The real noise was a sliver of hookup wire stuck in the socket shorting out a few pins... took me a while to find that. A country DI had a similar RCA amp setup and the owner wanted radio sound so he bought an "elcheapo" mini FM transmitter and got his young projectionist to hook it up. The instructions from the supplier were to connect it to the "grid cap" and it will work a treat!!! Guess which grid cap they tried.. YUP the 807! When I went there later on there were 2 rather charred looking FM transmitters sitting on base of the rack... loved to have been there when they went up. Lindsay  |  IP: Logged Jeff Stricker Master Film Handler Posts: 481 From: Calumet, Mi USA Registered: Nov 1999 posted 08-05-2003 06:57 AM                     Not to mention a bunch of amateur radio receivers and transmitters around here, I use a pair of McIntosh MC-40's (PP 6L6's) in my screening roon. Great sound  |  IP: Logged Jeff Stricker Master Film Handler Posts: 481 From: Calumet, Mi USA Registered: Nov 1999 posted 08-05-2003 06:58 AM                     Not to mention a bunch of amateur radio receivers and transmitters around here, I use a pair of McIntosh MC-40's (PP 6L6's) in my screening roon. Great sound  |  IP: Logged Edward Jurich Master Film Handler Posts: 305 From: Las Vegas USA Registered: Jul 2003 posted 08-05-2003 08:40 AM                     I'm going to attempt (my first try at this) to attach a couple pictures of that 1939 E.H. Scott radio. It's got 2 chassis and they are all chrome plated. Here's what it looks like in the cabinet after refinishing. The top lifts up (original) so the radio chassis can be viewed. [ 08-05-2003, 02:28 PM: Message edited by: Edward Jurich ]  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 08-05-2003 12:52 PM                        quote: A country DI had a similar RCA amp setup and the owner wanted radio sound so he bought an "elcheapo" mini FM transmitter... 2 rather charred looking FM transmitters sitting on base of the rack. Yup. Too often, I've run into drive-ins that have hooked their transmitters up to the outputs of their main amplifiers... then wondered why their old speakers sounded better. ED... nice looking load of chrome you have there! All that metal around the tubes reminds me of the McIntosh amps the phone company used to put in their central offices for distributing background music for Muzak, etc.  |  IP: Logged Jeff Taylor Jedi Master Film Handler Posts: 601 From: Chatham, NJ/East Hampton, NY Registered: Apr 2000 posted 08-05-2003 01:50 PM                     Although I grew up in the vacuum tube age, I use a QSC 800 in my home screening room (mono) driving a Yamaha 12" and horn PA cabinet for the "stage" channel, and a Yamaha 18" subwoofer in bi-amped configuration. I also use a subharmonic synthesizer for a bit more punch. I'm very happy with the QSC, but my engineer son who builds knock off Fender tweed amps for a hobby/side business is trying to talk me into going back to tubes. One thought I had was an Altec 1570 (811's) for the sub, and a 1569 (EL-34's) for the stage channel. Any of you guys have any thoughts on the subject--other than the fact that I'd be trading a nice cool compact setup for one hot rack? My other thought was to "upgrade"? to an Altec horn for the stage channel in lieu of the Yamaha cab, but then I've got the issue of most of the drivers you see kicking around being 24 ohm or so. No problem for a tube amp, I agree, but for the QSC it could be. All thoughts appreciated.  |  IP: Logged Jeff Stricker Master Film Handler Posts: 481 From: Calumet, Mi USA Registered: Nov 1999 posted 08-05-2003 07:28 PM                     Ed, the Scott looks terrific! What excellent radio gear. I have a Scott RBO (military version - that I'm currently selling)--- what excellent fidelity off the AM broadcast band! There used to be a station in Chicago that was particularly broad banded that played music from the 40's and 50's -- it sounded great. I have a friend who lives near here who is a big collector of Scotts.  |  IP: Logged Aaron Sisemore Flaming Ribs beat Reeses Peanut Butter Cups any day! Posts: 3061 From: Rockwall TX USA Registered: Sep 1999 posted 08-06-2003 02:50 AM                     quote: One thought I had was an Altec 1570 (811's) for the sub While it is one of the most powerful tube amplifiers around, the 1570, in my opinion does not do very well with bass frequencies below 150 Hz. (extreme distortion and a definite lack of 'balls' in the bass) I would go with a solid state amp for the sub, and tubes for the other channels, or if you absolutely INSIST on driving the sub with a tube amp, try building something using a 'bass-friendly' beam-tetrode based (6550's or 6146's) output a la Ampeg SVT. The QSC amps will handle a 24 ohm load with no problems other than maybe a slight loss of power... -Aaron  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 08-06-2003 03:44 AM                  For driving subs with tube-type amps, and audio amps in general, it is not necessarily all that important to have tubes like the 6L6GC, 807, 6146B, 6550, etc. There are many great triode amps that outperform a lot of those beam power pentodes types. What is important, is the design and construction of the output transformer. For any size power amp, the $$$ sunk into that xmfr will more than pay for itself in performance...especially at the low freq and high freq ends. Also just as important, especially for bass reproduction, ya need a big ol' "stiffie" ...A power supply that wont sag when required to supply sustained high current. Not just big filter caps, but BIG efficient low-impedance power transformers (or switchers) as well. BTW: Ed, that Scott is a honey! It is in fantastic shape! >>> Phil  |  IP: Logged

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