vacuum tube stereo

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Originally Posted By: mjoekingz28
Originally Posted By: Red00Jetta
Also stay well away from any of the capacitors if you do it yourself. I got the
eek.gif
knocked out of me by one of the big ones on my amp. It can kill you, so be careful.


What time period are we talking for the complete receiver (capacitors and all) to lose their charge once the plug is pulled?


Any high voltage ones will hold charge from several minutes to maybe half-hour, depending on it's capacitance and how the circuit is being executed.

Your best bet is to build (using 2 sets of alligator clip wires + 5K wirewound resistor (2 to 5 watts ok) and use it to discharge any high voltage section residual charge.

That's how I do it, even on high voltage amps (e.g. 211/845 SE which runs between 950V up to 1.2kV on B+ banks).

Q.
 
Originally Posted By: Quest
Shure V15-type3 (speaking about going retro, that cart body is over 40 yrs old now, still sounds warm and nice with decent body and definition for MM type)


Was the Shure V15 the one that was supposed to be able to play warped records really well? Something I was also wondering,are there any advantages to a moving coil vs moving magnet cartridge?
 
Also @ OP:

Word of caution: tube amplifiers have high voltage sections (typically from 280V DC and upwards, and can go as high as 500V DC). If you do not have any experience in dealing with such high voltage and/or you are not comfortable with it, don't do it. Pay someone experienced to do it for you instead.

Shocking yourself isn't fun at all; worse yet: if you have heart problem,etc. such shock might cause your heart to stop and much much more (may even electrocute you if you have a weak heart).

So please take note and treat this matter seriously.

**disclaimer: you have been warned**

Q.
 
Originally Posted By: aquariuscsm
Originally Posted By: Quest
Shure V15-type3 (speaking about going retro, that cart body is over 40 yrs old now, still sounds warm and nice with decent body and definition for MM type)


Was the Shure V15 the one that was supposed to be able to play warped records really well? Something I was also wondering,are there any advantages to a moving coil vs moving magnet cartridge?


You are talking about V15Type4 (little brother of V15Type3), and later version: V15TypeMR... both of these comes equipped with viscous damped carbon fibre brush at the front of of the needle guard where when lowers, will also act as a damper to damp the warp records while the needle rides on it.

If you know what Sony biotracer arm is, then it has the built-in capability to electronically dampen the arm so that the needle will ride smoothly even on a moderately warped record, resulting in no woofer pumper (thus no need for "subsonic filter")

Q.
 
moving coil (aka "MC") carts has certain advantages, but due to the delicate workmanship (thus high initial cost during manufacturing), the extra time/workmanship involved in bonding the needle onto the shank,where the base is where the coils are, etc.) coupled with exotic stylus profile (VanDanHul,hyper-elliptical, FG60, etc.), the resulting device purchasing cost can be prohibitive, given the performance it attains when compared to a decent MM cartridge.

While the Japanese manufacturers are still making MC carts (Shelter, Sumiko, Koetsu, Audio Technica, ZYX, Denon, etc), and ditto with some European ones (Ortofon, VanDanHul, BenzMicro, etc.), they pretty much own the MC cart market nowadays so you are expected to pay premium for it.

The cheapest MC cart can be had would be Denon 103, which comes with elliptical stylus and sounds quite decent.

The mid-grade stuff should be Shelter or Ortofon, but expect to pay at least 400bux and upwards. Premium ones such as Koetsu, high end BenzMicro, etc. would cost you at least 2K or more.

I'm a cheep person and been growing up (I also design MM phono stages, from my teenage years with tube SRPP MM gain stage, to now using high-speed Op amps, etc.), so naturally, I'd go with MM carts.

AT440 can sound very, very good if it matches your tonearm. Cost is not bad at all.

Those who fall for fine line contact/or fine line nude, etc., the venerable (long discontinued AT125LC are one of the best-sounding Japanese mass-produced MM carts IMHO, and I have one with fresh new needle on it).

Other times, I use my Shure V15Type3 for general listening (I have stocked up on JICO replacement needles, so I can spin my vinyl for a loooong, loooong time).

Q.
 
Oh, in terms of MM vs MC, each has their strengths and weakness(es):

MM: strengths:
-good ones can be had recently priced
-replacement needles easy to come by
-decent/good sounding to excellent sounding (comes close to some mega-bux MC carts of same price or even more)depending on the quality and the design profile of the stylus (needle) and more.
-much easier to find proper matching with medium to medium-low mass tonearms.

(*low mass tonearms need not apply, for the days of ultra low mass carts are long gone, and most manufacturers nowadays no longer makes them cartridges*)

-standardised input loading to 47kOhms.

MM weakness:
-depending on needle profile, design, execution, etc. some can sound rather dull, or lack of definition.

MC: strengths:

-typically with a slightly tilted high frequency response part, it gives music an extra bit of "airy" or "definition".

-channel separation in general, are just a wee tad better than that of the older designed MM carts.

-if money is of no objection: MC carts you can find a garden varieties of rather exotic stylus profiles (priced accordingly also).

MC weaknesses:

-high initial cost.

-high needle replacement cost (must be shipped back to manufacturer or special repair shop to re-tip)

-non standardised loading (can be from a few ohms to around 100ohms).

-low output type requires additional gain stage, or costly step-up transformers.

-typically goes well with medium or medium-low mass tonearms. Some requires high-mass tonearms (example: Ortofon SPU series)


Q.
 
Originally Posted By: Quest
-high needle replacement cost (must be shipped back to manufacturer or special repair shop to re-tip)


Man that right there makes me want to never own an MC!
 
My turntable has a Shure R1000EDT cartridge. I just replaced the needle on it (elliptical) for only $11. Sounds amazing and plays scratched up records flawlessly! I think I'll stick with that haha :p

What I would love to have (I read about this on an audiophile forum) is a monophonic cartridge.
 
If you plan on fixing the unit yourself, read through the following link below. It'll give you an idea of what radio restoration is all about:
http://antiqueradio.org/recap.htm

This is where I order replacement parts for my radios:
http://www.justradios.com/

For further help, this web site is very active and full of helpful folk. It's the "bitog" of antique radios:
http://antiqueradios.com/forums/index.php

If you are willing and able to perform soldering tasks in a radio chassis, you should be able to restore it yourself.
 
Sorry guys, I was out for a few days with a bad back. Lots of good info so far though, thanks. Yep, I know how dangerous those caps can be, along with the selenium rectifiers. I tried my own rebuild with a VOM 1428 amp that didn't go well, so I sent it to a member from audiokarma.org who got rave reviews from other members. I haven't heard from him in over a year and he was older than dirt, so I just assume he passed on.

I let it go and picked up this GE, with the intention of finding a company that specializes in restorations. I've been looking at a place called classic tube audio, the guy there says he can take care of me. Anyone have any experience? My dream is to get my amp returned to glory and hooked up to my coral speakers and professionally restored pioneer turntable.

P.S. I think the pots might be beyond deoxit at this point, so I didn't bother to try it. There is a loud buzz that tells my novice ears that the can caps are probably dry to the point of rattling.
 
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