3dzapper
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Posts posted by 3dzapper
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"The volume specs range from -80db (silent, no volume) to 0db (what the manual calls 'max volume') with the capability to go to +10db, which I assume would be insanely loud."
If the volume scale is true logrithmic, each 10 Db of power increase read on the display represents a doubling of power and will result in a 3 Db increase in volume from the speakers. Thus if 0 Db on the display represents 65 watts, -40 would be 4 watts. With 90 Db @ 1 Watt efficient speakers, this is 96 Db at 3 feet from each speaker and approximately the same level when two speakers, room and distance are factored. While 96 Db is loud, it is not so loud as to prevent conversation.
As others have noted, older volume control tapers added most of the available power in the first half of rotation. The position of the knob itself was not the determinate factor.
Hope this simple explaination helps.
Rick
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Sput, April is the best time to visit DC. It's beautiful at cherry blossom time. Weather is generally in the seventies, pleasant. From there, maybe Nags Head down to Hatteras on the outer banks of North Carolina or up to Atalantic City, an hour and a half's drive to Philly for a day. Another hour and a half to the Amish Country in Lancaster County.
Rick
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Why all this talk about smoking? Craig said the amp didn't smoke.
Nice work Mr O.
Rick
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OK I see your confusion Robert. The "Pre-amp socket" Ned is refering to is the octal socket on the back of the chassis. In addition to being a bias test point, that socket was designed to provide power to some of the pre-amps of the time.
I typed this a while ago. Then we went to Lowes. Senior moment, I forgot to hit post.-(
One thing I don't see in the manuals is a hook up between the KT's chassis and the test/pre socket. In the original Mark III manual and build, both KTs combined bias is measured at pin 8.
Make sure that the wire from one KT's pin 1/8 to the other is removed, the bias measurement will then be taken across each tube's 10 Ohm cathode resistor. To measure bias from the back test/pre socket, a piece of hook up wire must be run from pin 1/8 of each KT. One would go to pin 8 of the test socket, the other to pin 5. Those biasing instructions then begin to make sense.
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GRRRR!!! The internet ate my post!!!!
Those instructions you cited are to set the original bias into a safe range for final bias adjustment. Once it is done, there is little likelyhood that it will ever be repeated.
The final bias is measured from pin 8 to ground across the 10 Ohm resistor. There are instructions on how to safely measure final bias on the octal at the back without removing the base in Uncle Neds Poseidon manual on page 8 step 7.
(download here: http://www.diytube.com/unidriver/poseidon-tz.pdf )
Rick
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"It will be Low, Hi and ZeroGain Buffer."
Great idea Mark!!![Y]
Rick
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"Edit: Check with my meter and it looks like the resistor connected to the diode is a 1K. The resistor on the pot connected to ground is fun. It should be the 18K but appears to be marked a 7.6K and it is hard to tell and when I place the meter on it... it climbs rapidly and then slowly to 9.94K. I am assuming because it connects to a capacitor I can't get a reading of the resistor itself and I am witnessing the cap charging?"
The original circuit from the diode to ground was 29KOhms, With the change to a 25K pot plus 7.6K and the 1K is 33.6KOhms. You should be OK. More of the voltage will drop across the pot, that should give more adjustability.
Rick
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On my amps, the 100k resistors rather than fixed, are pots tapped at the output of the 1K resistor. Each tube can then be biased individually.
Hey! Want a nice tube tutorial? http://www.du.edu/~etuttle/electron/elect27.htm#PowTri
Rick
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Woo, Check out this site. They have a wide selection of grill material if that is the route you chose:
http://www.acousticalsolutions.com/products/fabrics/grille_cloth.asp
Rick
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Steel wool in the horns? Chicago? Did Tom "Chainsaw" Brennan ever own those Cornwalls?
I wouldn't worry about the x-over boards. PWK probably made them from scraps left over from enclosure cuts to save a dime.
Have fun!!!!
Rick
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C'mon Robert, let those fingers in there! You're no fun.
Looking good. I've decided to get a pair to try in my clones. Just waiting for a change in the billing cycle if you know what I mean. I have to post a question I have to Shannon's forum.
Rick
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That pre sure is pretty!
Looks like something that Wardsweb could have built. We all admire his talent. (Or, like me. are green with envy.[+o(])
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I wonder if the guy I lent my 299B to is done listening to it yet?[:@][:@][:@]
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"What have you folks heard?"
I was told by police to knock it off at about 11PM at a big outdoor party. The city ordinance was for 55dBA (fifty-five) at the property edge after 9PM.
It was 85dB in the front yard of the complaining party (a half-mile away).
This implies 133dB at 10 feet.
It probably was that loud as there were 8 LaScala bass cabinets, another pair used as mids, 6 high frequency horns, 10 tweeters, and a pair of LaScala industrial as side fill monitors (and 4 Cerwin Vega floor monitors. About 2KW in tri-amp for the mains.
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How important are wires to audio? Once, my stereo wouldn't put out any quality sound so I checked the wires. Sure enough, it was unplugged.
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Always a gentleman, a family man and a great American, may he rest in peace with God.
Rick
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Hey Guys, Meagain too, thanks for an interesting read.
Back in the "real" tube days" if you were to order a large volume of tubes from say GE that they didn't have sufficient inventory or scheduled capacity to fill, GE was just as likely to buy a batch from Tung-Sol, badge them and send them off. It seems the more things change, the more they stay the same.
Rick
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Chris, Good advice so far. More caveats, start from the middle and work out towards the ends and use a dry iron, no steam.
Once the center is glued and pressed, I use the wood block edge pressing method, it's easy to hold the banding in place with one hand while heating and pressing with the other. Then hit it with the block before it cools.
If you mess up a strip, it comes off easily with a razor knife dragged along behind the hot iron.
Rick
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Actually in testing with a scope I have found those tone controls usually have a dead flat position about half way from +1 to -1 on almost all Scott amps. If I rebuild them and find it off with a scope I adjust the controls via set screw to correct it. If they have not been removed from the amp since it was here straght up is straight up..........LOL!!! 95% need no adjustment.
I figured that you would do that when you went through one Craig. Of course, the operative is "about half way".
I don't know the history of the 299 in question.
Merry Christmas.
Rick
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I have an older ('84) pair of Heresys. After some tweaking back to metal K-700s and K-55vs and judiciously adding my SW-15 subwoofer, I was surprized at how close the sound came to my '77 Klipschorns. Just "smaller". 2/3s of a Klipschorn the old ads read.
Enjoy!!!!
Rick
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Some will probably argue with me, but here is my take on those vintage amps (not the sound of them):
Those "lines" being straight up on the tone pot knobs mean little. Years and old manufacturing tolerances have moved the null point away from dead center of the pot's rotation. My advice to owners of these type amps is to remove the knobs, manually center the pots, and then slightly adjust the controls until the system sounds and/or measures flat. At that point reinstall the knobs with the indicator lines straight up. Now, the lines mean something!
Rick
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A couple of "must haves" in any collection of female artists are:
Carol King "Tapestry" .She is a songwriter extraordinaries and many of the songs on this album have become huge hits by other singers.
Linda Ronstadt "Heart like a Wheel". This was her real breakaway album from the Stone Ponies. She put more heart into this album than into anything she has done since IMO.
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Sam Tellig (thanks Coda), the chap who wrote the recent review of the LaScala IIs and bought them, drives the Scalas with Sun Audio 2A3 amps. I believe his are SET but he has raved over them for years.
If they are as good as or better than my Wright Mono 10 2A3PPs, they are winners in the 10 watt contest. One 2A3PP I'd love to hear is the one Dr Jeff designed and built a few of. I can't remember too many of those changing hands, must be pretty good.[
]One more note: PWK for years played PP 2A3 amps , Brook Model 12k on his Khorns.
Rick
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Come on lets get some imagination.
How about Janis Joplin: "Pearl"
Genya Ravan/Ten Wheel Drive: "Construction 1"
Mary Travers/Peter Paul and Mary "Ten Years" for a start
And yes, I prefer to listen to Nora Jones/Handsome Band over Dianna Krall.
Rick
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Klipschorn dispersion and bass response
in 2-Channel Home Audio
Posted
Dr Who's sig is relative here: "it's a compromise".
Maggies use the room boundries more than horns to present their "spacious image". This presents it's own set of problems with placement, etc. With Khorns, it's easy: stuff 'em in the corners.LOL
More bass from the maggies or distorted bass? You decide. Here is the anechoic plot published by Stereophile: http://www.stereophile.com/floorloudspeakers/595/index6.html