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Author Topic: Vacuum Tubes Jeff Taylor Jedi Master Film Handler Posts: 601 From: Chatham, NJ/East Hampton, NY Registered: Apr 2000 posted 08-06-2003 09:44 AM                     Phil and Aaron, thanks for the feedback on tube bass amps. Any thoughts on going to an Altec horn (or are there any other recommended horns?) for the main "stage" channel of my setup?  |  IP: Logged Edward Jurich Master Film Handler Posts: 305 From: Las Vegas USA Registered: Jul 2003 posted 08-06-2003 04:27 PM                     The Scott radio came from Chicago (LaGrange, Il) and is my wifes grandfathers who bought it new around 1939. Check out the chassis underside, the big wheel in the middle is part of the band switch. It rotates with the band switch, has contacts on the underside for the different coils. Below is a view of the underside showing the coil contacts. Below is a view of the chassis contacts that connect with the coil wheel. Note that it is gear driven. There are 2 other switches that switch with the coil wheel and all three have to be in sync. When I refinished the cabinet I did not strip the original finish. The original finish was still in good shape, it just had a couple bag gouges and several scratches. I filled in the gouges and wiped the cabinet down with stain and all the scratches filled in. Then gave it some coats of new varnish and buffed with very fine steel wool. There are still some minor dents in the cabinet that don't look bad but then it is an antique.  |  IP: Logged Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 08-06-2003 06:41 PM                     I have to agree with Phil Hill about transfer design. Transformer engineering is one of the "Secrets" to sucessful amp design! For anyone interested, Western Electric 300Bs are now being produced again, and are not cheap for a matched pair! They can easily be found on the "www" Vacume Tube Logic is one of the vacume tube amp powerhouses in the industry today, and are located in Ontario, CA. Anyone who is interested should view thier books regarding amp design. These books are legendary, but on one hand, they do omit some vital info. I have to disagree with Mark G. regarding how tubes are outdated. There is nothing that can beat tubes for sure sound quality! One funny experiment that I recently tried. I went into a local hi-end store to check out some new vacume tube systems that they had. I had a Sinatra c.d. on hand, and the tubes made it sound awesome, while the hi-end transistor amp, played back through the same c.d. player, pre-amp and speakers made it sound ho-hum. The tubes really made the c.d. sound rich and full...and gave a lot of warmth! The funny thing was that the store had a "rap" c.d. on hand, and I thought that it would be funny to listen to it on tubes. The rap recording was crap to begin with, so imagine how the tubes added the same warmth and ambience that it did to the Sinatra recording! RAP IS NOTHING BUT TEST TONES WITH VOICE OVERLAYS!  |  IP: Logged Bruce McGee Phenomenal Film Handler Posts: 1776 From: Asheville, NC USA... Nowhere in Particular. Registered: Aug 1999 posted 08-06-2003 09:01 PM                     Ed, that Scott radio is fantastic! I sure wish they still had all that detail in modern equipment! When todays 'stuff' is 60 years old, how much of it will still be running?  |  IP: Logged Lindsay Morris Expert Film Handler Posts: 233 From: Darlington, WA, Australia Registered: Sep 2002 posted 08-07-2003 03:45 AM                     Ed, That Scott is out of this world... never seen a think like that here in Australia. Have tangled with plenty of bandswitching radios in the past but most of those were of 1950's vintage... but the Scott is something else, an excellent restoration job and I hope it sounds as good as it looks. On the subject of "subs" and valve amps I must admit that I cheat a bit at the outdoor and run a powered sub parked in the "W" bin with the pair of 15" normal bass units just to add a bit more grunt... The bass disperses rather rapidly outdoors so I took the easy way out and added a Studio Acoustics 12" 100 Watt unit which just cruises and just gives that nice deep "thump" to the very low sounds and effects. On their own the pair of 15" drivers do a really good job but needed a little help. Certainly the output transf needs to be well designed but many of those cinema type units from the 50's and 60's were well done with plenty of copper and iron and well done windings and most of the cinema amps I have come across have had plenty "of GO" at the bottom end. When I get a decent snap I will post a picture of the DI amp I have just repaired. Load tested for 24 hours at 108 watts RMS from a sinewave signal (onset of clipping on the scope) and mains trannie just warm and less warm was the output stage.(The hottest thing was the dummy load!!) Weight of the animal is around 25KG so not the sort of thing you use in the lounge room but really sounds nice when driving a big speaker setup... very clean. Now I will get back to completing my new amp rack ready for stereo sound conversion. Lindsay  |  IP: Logged Edward Jurich Master Film Handler Posts: 305 From: Las Vegas USA Registered: Jul 2003 posted 08-07-2003 08:57 AM                     I have a friend who thinks I'm nuts when I say tubes sound better for audio. However, here's something I did a few years ago that says otherwise. I was Chief Engineer at WWMX radio in Baltimore (also known as W-MIX then) from 1988 - 1992. I built new studios for them and had everything running top notch. However, while sitting at home listening to the station, it just seemed to me that something was lacking in the sound. I remembered that years eariler my brother-in-law had a mono HiFi that sounded better with more realism than my stereo radio station. Then it dawned on me that is was all tube. So, after 20 years of not touching a tube, I bought a bunch of 12AX7's, tube sockets and started building a vacuum tube audio leveling amp. I came up with a 12AX7 gain control stage so everything in the audio path is triode. One night I installed my vacuum tube leveling amp in front of the Orban Optimod ( a modern soild state audio processor ). I backed off on some of the Orban processing and let my vacumm tubes do a lot of the audio leveling. I did this without telling anyone. And the result was fantastic, the station had realism like I had not heard in years. After a couple weeks one of the other station engineers in town called to let me know how great my station sounded. I had other people tell me how good the station sounded. The best one though was when a music consultant heard the station while driving through Baltomre and stopped by to see why our station had such a "unique" sound. I opened the back of the rack so he could see all the tubes glowing, his mouth dropped wide open. That station had an increase in ratings (number of listeners) while that tube processor was in use. I built that tube processor at home with my own parts so it went with me when I left the station. I still have it although it's been collecting dust the past 4 years since I've been out of radio.  |  IP: Logged William Hooper Phenomenal Film Handler Posts: 1879 From: Mobile, AL USA Registered: Jun 99 posted 08-08-2003 01:25 AM                        I don't understand, Ed. Tubes? Is this some sort of intravenous music delivery system? Like that special microphone at the CBS news station in Chicago?  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 08-08-2003 10:01 AM                  Bruce said: quote: When today's 'stuff' is 60 years old, how much of it will still be running? Probably most of it...IF it ain't thrown away like this "disposable" generation seems to like to do. I can see it now: 60 years from now when Josh is 79 and all of us are dead, he will be still posting on the net (or whatever is around then), looking for carts for his machine....he will be a true patriot and carry on history! >>> Phil  |  IP: Logged Edward Jurich Master Film Handler Posts: 305 From: Las Vegas USA Registered: Jul 2003 posted 08-08-2003 10:37 AM                     William Hooper said "I don't understand, Ed. Tubes? Is this some sort of intravenous music delivery system? Like that special microphone at the CBS news station in Chicago?" I can't believe you remember the microphone gag. Back in the early 70's while I worked for WBBM (CBS) in Chicago, the TV guys pulled a gag on a new news person. They brought out one of the highly directional Electro Voice microphones that had a 2 foot long by 3/4 inch dia element. They told him it was one of the "new" rectum microphones. One of the other news guys ran a mic cable down his pants so the connector was hanging out his pants leg and said, "I've got one on now". On the subject of stuff lasting 60 years. I don't think there will be a lot of what's in use now around in 60 years. For one thing, standards are changing so fast that things become unusable much faster now. And, with surface mount electronic parts, stuff will be just plain unrepairable after a few years.  |  IP: Logged Paul Konen Jedi Master Film Handler Posts: 981 From: Frisco, TX. (North of Dallas) Registered: Jun 99 posted 08-13-2003 11:04 AM                     To further justify that people realize that tubes give audio a better sound Tube SACD CD Player  |  IP: Logged

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