Are you kidding? I have a friend whose first job was as a field engineer for a company that made sound panels for recording studios; he ended up babysitting new installations during a number of recording sessions in the late 60's, early 70's.
The "low level signal processing" chain went guitar -> amp -> speaker -> air -> microphone -> sound panel -> tape.
So they certainly _did_, and most likely certainly still do.
-- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" gives you just what it says. See details at http://www.wescottdesign.com/actfes/actfes.html
And they used springs for reverb [1]. Nothing has changed in 40 years?
John
[1] or in at least one case, a speaker and a mic in a men's room.
Dr. Z has forgotten more about tube amps than I'll ever know. I've been to his shop and know that he has specially made transformers, Capacitors (orange drops) and other components made for his amps. He is so into vintage tube sounds that when Sprague changed from polystyrene to polyester or vice versa) insulation in their caps, he had special runs made with the older material. He claims he can hear the difference.... I can't. You may be able to talk him into selling the parts you need if you are really intent in building your own tube amp.
John
Those of us "in-the-know" realize that HEADROOM is where it's at!
...Jim Thompson
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| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
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| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine Sometimes I even put it in the food
Random tips:
1) If you intend over-driving a push-pull output stage, use a long-tailed pair for the phase splitter.The type of phase splitter which derives its balance from the centre point of the grid resistors of the output valves will produce horrible L.F. effects when those valves run into grid current. A phase splitter of the type with with equal anode and cathode load resistors has unequal driving impedances and will also give bad-sounding distortion on overload.
2) Valve circuits are only the same as transistor circuits in their overall function, in all other respects they are very different indeed.3) Never leave a valve amplifier output open-circuited *ever*!!! ...not even for a millisecond. It is so easy to generate very high voltages in the transformer winding which will cause a flashover and ruin the transformer, the valves or the valveholders (or start a fire or give you a nasty jolt).
4) Valves need high voltages, high voltages kill. If you only think you know what you are doing, get someone who really does know how to handle high voltages to help you.5) The size of the output stage dictates many other things such as the size and type of power supply, the type of driver stage, the overall configuration, the overall gain and feedback ratios. (There is nearly always far less overall feedback in valve amps than there is in transistor amps.) Start your design with a specific output stage and work forwards and backwards from there.
6) Read as many books on basic electronics from the 1950s as you can. They were written by people who designed things with valves because they only had valves, not because they were fashionable. They had to make them to a price, make them work properly and make them meet specifications, not look pretty with reams of bullshit to sell them.In the U.K. try to find and study: "The Foundations of Wireless" - M.G.Scroggie "High Quality Sound Reproduction" - James Moir "Circuits for Audio Amplifiers" - Mullard Ltd. "Wireless World" - Iliffe (any editions you can get your hands on)
No doubt U.S. readers can suggest similar publications.
-- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk
I'll bet there are bands out there that still use all the "old stuff", and swear by it.
And plenty of bands that are all transistor.
-- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" gives you just what it says. See details at http://www.wescottdesign.com/actfes/actfes.html
That's not true. I do a fair amount of work in recording studios, and a guitar amp with a microphoe in front of it is a common sight.
-- Guy Macon
It's the cathodes that are supposed to glow.
Real tubes are ceramic, and water or forced air cooled.
-- http://improve-usenet.org/index.html aioe.org, Goggle Groups, and Web TV users must request to be white listed, or I will not see your messages. If you have broadband, your ISP may have a NNTP news server included in your account: http://www.usenettools.net/ISP.htm There are two kinds of people on this earth: The crazy, and the insane. The first sign of insanity is denying that you\'re crazy.
Some people need more headroom than others. In fact, their heads ar so big that they need a shoehorn to get their head through the doorway. Luckily, I have them kill filed. ;-)
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There are two kinds of people on this earth: The crazy, and the insane. The first sign of insanity is denying that you're crazy.
Always wondered if there was such a thing as a live rock concert.
Tam
Real men build amps where the plates are at least cherry red. If they don't, you are not pushing the envelope.
Tam
Um... actually I have build one guitar amp for my friend when he brought a kit and couldn't get it to work... How many guitar maps have you built my friend Jan?
What is going to kill you is the output transformer. Hint, learn, calculate it and wind it yourself. Buying them one or two at a time is quite cost prohibitive and very time consuming to find.
By the way, what is wrong with class AB1 push-pull with "ultralinear" transformers.
And the difference is what? Think about it.
Hell yes. If i want the tremendously loud 1 watt average acoustic (+120 dBA) in a living room, i will choose very efficient speakers, and an about 400W per channel and 1000 W suborder amplifier. BTW 10 W acoustic fills a sports stadium nicely.
I expect that you know, for good broadband performance most microphones and speakers are less that 0.1% efficient. Good mic's are about -60 dB.
Decent music audio has about a 4:1 to 6:1 crest factor and about 20 dB dynamics. Better audio is even higher. This is where headroom comes into play. If i want 1 mW rms in my headphones, i require a 20W or more amplifier to meet these conditions.
theres a fix for that. a series of power diodes on each plate, anode to ground and high voltage disk cap across them plate to ground, stops back emf from transformer from flashing over the tubes.
A Metrosil always struck me as the most appropriate way to do the job, but they were not obtainable in small quantities when I needed them. I have made an anode-to-anode spark gap from two battery carbons on a ceramic tag strip.
People who have never worked with valve designs on a day-to-day basis need to be told these things before they find out the hard way - and I don't know of any textbook from the valve era which mentions this because it was so well-known at the time.
My own preference for P.A. amplifiers is a fixed dummy load, chosen to just keep the voltages within safe limits and wired directly across the transformer terminals. You lose a bit of power that way, but you don't lose the amplifier when someone trips over the speaker wiring.
This can't happen with a built-in guitar amplifier until: a) The loudspeaker goes O/C b) Someone adds a switched extension loudspeaker socket and plugs in a disconnected speaker.
...but you can still get an accidental O/C with a prototype on the bench if you are not careful.
-- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk
On a sunny day (Tue, 14 Oct 2008 23:14:25 -0500) it happened "Jon Slaughter" wrote in :
Well, do not remember the exact number, but the one with 4 EL84 I build has much to my surprize become a classic item:
Remember EL84 x 4 is at most 35 W.
So, design a classic and come back :-) LOL.
Now that really propped up my ego.
On a sunny day (Tue, 14 Oct 2008 18:07:15 -0700 (PDT)) it happened snipped-for-privacy@netzero.com wrote in :
Yep, but they are so hard to see.
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