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#1
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"matched" tubes on ebay
This weekend I rescued a beautiful old Dynaco
Stereo 70 amplifier from the dumpster at the recycling center. It's in good shape, but the output EL34's are of all different manufacture. I'd like to get 2 sets of matching pairs for replacement. I take a look on ebay and there's a zillion people selling matched pair EL34's. How do I know that they are truly matched? There's never any statements about how they are matched. For all I know, "matched" means the same manufacturer. On one website I looked at, the writer suggested matched Tesla EL34's for good performance at a reasonable cost. Any opinions on this? Where can I get two pairs? |
#2
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tube matching is the source of a lot of controversy
you can match tubes on transconductance, plate current, or several other factors there are even well respected experts who feel that the best sound comes from tube pairs that are somewhat un-matched (R.G. Keen, for example) JJ/Tesla tubes are a best buy, but I would also say that SED "winged C" sound as good or better, and are just as good of a buy, perhaps even a better choice. I recommend you test the tubes you already have on a calibrated transconductance tube tester i.e. Hickok, TV-7D/U, etc. the ones already in there may be better made and better sounding than anything you can buy new, if they are not worn out don't worry if they are not "matched", or of different manufacture, as long as they are similar in their transconductance characteristics and condition, they will be great tube "matching" is way overrated tube biasing is what you want to worry about! now that IS important! PS - examine the tubes carefully, the best tubes typically have welded (soldered) plates, and opposed to stapled plates if you can determine the original country of origin, that is another good indicator my order of preference - britain, germany, russia, czech republic, yugoslavia (avoid usa and chinese EL34) "Jim Stewart" wrote in message ... This weekend I rescued a beautiful old Dynaco Stereo 70 amplifier from the dumpster at the recycling center. It's in good shape, but the output EL34's are of all different manufacture. I'd like to get 2 sets of matching pairs for replacement. I take a look on ebay and there's a zillion people selling matched pair EL34's. How do I know that they are truly matched? There's never any statements about how they are matched. For all I know, "matched" means the same manufacturer. On one website I looked at, the writer suggested matched Tesla EL34's for good performance at a reasonable cost. Any opinions on this? Where can I get two pairs? |
#3
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On Mon, 25 Oct 2004 17:40:45 -0400, "arizona cowboy"
wrote: lots of solid advice snipped for bandwidth (avoid usa and chinese EL34) The Chinese part is obvious, but the USA part may seem strange. But it's good advice for use in lots of antique amplifiers. The American 6CA7's seem to motorboat in bone stock, up to speed, all good stock values, machines. FWIW. Chris Hornbeck |
#4
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Jim Stewart wrote: This weekend I rescued a beautiful old Dynaco Stereo 70 amplifier from the dumpster at the recycling center. It's in good shape, but the output EL34's are of all different manufacture. I'd like to get 2 sets of matching pairs for replacement. I take a look on ebay and there's a zillion people selling matched pair EL34's. How do I know that they are truly matched? There's never any statements about how they are matched. For all I know, "matched" means the same manufacturer. On one website I looked at, the writer suggested matched Tesla EL34's for good performance at a reasonable cost. Any opinions on this? Where can I get two pairs? I have what you need. Lord Valve Tone Chaperone VISIT MY WEBSITE: http://www.nebsnow.com/LordValve I specialize in top quality HAND SELECTED NOS and current-production vacuum tubes for guitar and bass amps. Good prices, fast service. QSC amps, RNC compressors, lots of other good stuff! Partial Client List: * Derek Trucks/Allman Brothers Band * * Meatloaf * Catherine Wheel * Yo La Tengo * Let's Go Bowling * * Rob Hyckys (guitarist for Commander Cody) * Waky Amps * * Fleetwood Mac * Tyrin Benoit * Eugene Fodor * Dale Bruning * * Komet Amplification * Dr. Z * Maven Peal * Blockhead Amps * * Jim Kelley * Balls Amplification * Roccaforte Amplifiers * * Gerhart Amplification * Aiken Amplification * The Right Half of AGA * * Lots More * NBS Electronics, 230 South Broadway, Denver, CO 80209-1510 Phone orders/tech support after 1:30 PM Denver time at 303-778-1156 - Our 23rd Year - VISA - MASTERCARD - PAYPAL Philo T. Farnsworth sez, "Vacuum tubes kick major ass. Be a MAN...and buy some TODAY!" |
#5
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Tubes need to be matched only when used in push-pull pairs as in the Dyna;
ideally, they should have same characteristics in terms of both - quiescent current at the working point, in order to balance DC flow through the output transformer, thus reducing iron core saturation and improving bandwidth - transconductance (gain), because each tube amplifies only half wave, therefore, should one have higher gain, the resulting amplified wave would have one half "bigger" than the other - distortion is produced. In real world, the first issue is not a problem at least within +/- 10% because OPTs are designed to handle some DC unbalance without problems and the second is neither too IF the amp has some feedback (like the Dyna) and the 2 tubes are not widely different. Ordinary "shop matched" tubes, sold by any reputable supplier, are usually tested on a good, tuned transconductance tube tester and sorted to much closer tolerances than it was done 40 years ago, when the Dyna was produced., therefore they will work perfectly (provided that they're correctly biased, ie. the amp's circuitry is properly working). Get a quartet of JJs or Svetlanas "winged C" as You prefer, they both provide top quality @ fair price. Ciao Fabio "Jim Stewart" ha scritto nel messaggio ... This weekend I rescued a beautiful old Dynaco Stereo 70 amplifier from the dumpster at the recycling center. It's in good shape, but the output EL34's are of all different manufacture. I'd like to get 2 sets of matching pairs for replacement. I take a look on ebay and there's a zillion people selling matched pair EL34's. How do I know that they are truly matched? There's never any statements about how they are matched. For all I know, "matched" means the same manufacturer. On one website I looked at, the writer suggested matched Tesla EL34's for good performance at a reasonable cost. Any opinions on this? Where can I get two pairs? |
#6
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LV, I didn't see any links to what you offer or pricing? Or do you email for
a price and availability? "Lord Valve" wrote in message ... Jim Stewart wrote: This weekend I rescued a beautiful old Dynaco Stereo 70 amplifier from the dumpster at the recycling center. It's in good shape, but the output EL34's are of all different manufacture. I'd like to get 2 sets of matching pairs for replacement. I take a look on ebay and there's a zillion people selling matched pair EL34's. How do I know that they are truly matched? There's never any statements about how they are matched. For all I know, "matched" means the same manufacturer. On one website I looked at, the writer suggested matched Tesla EL34's for good performance at a reasonable cost. Any opinions on this? Where can I get two pairs? I have what you need. Lord Valve Tone Chaperone VISIT MY WEBSITE: http://www.nebsnow.com/LordValve I specialize in top quality HAND SELECTED NOS and current-production vacuum tubes for guitar and bass amps. Good prices, fast service. QSC amps, RNC compressors, lots of other good stuff! Partial Client List: * Derek Trucks/Allman Brothers Band * * Meatloaf * Catherine Wheel * Yo La Tengo * Let's Go Bowling * * Rob Hyckys (guitarist for Commander Cody) * Waky Amps * * Fleetwood Mac * Tyrin Benoit * Eugene Fodor * Dale Bruning * * Komet Amplification * Dr. Z * Maven Peal * Blockhead Amps * * Jim Kelley * Balls Amplification * Roccaforte Amplifiers * * Gerhart Amplification * Aiken Amplification * The Right Half of AGA * * Lots More * NBS Electronics, 230 South Broadway, Denver, CO 80209-1510 Phone orders/tech support after 1:30 PM Denver time at 303-778-1156 - Our 23rd Year - VISA - MASTERCARD - PAYPAL Philo T. Farnsworth sez, "Vacuum tubes kick major ass. Be a MAN...and buy some TODAY!" |
#7
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Lord Valve wrote:
Jim Stewart wrote: This weekend I rescued a beautiful old Dynaco Stereo 70 amplifier from the dumpster at the recycling center. It's in good shape, but the output EL34's are of all different manufacture. I'd like to get 2 sets of matching pairs for replacement. I take a look on ebay and there's a zillion people selling matched pair EL34's. How do I know that they are truly matched? There's never any statements about how they are matched. For all I know, "matched" means the same manufacturer. On one website I looked at, the writer suggested matched Tesla EL34's for good performance at a reasonable cost. Any opinions on this? Where can I get two pairs? I have what you need. Maybe you could tell us what equipment you use and how you match your tubes and how much they cost. Lord Valve Massive sigvertizement snipped.. |
#8
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"Lou deGonzague" wrote in message ... LV, I didn't see any links to what you offer or pricing? Or do you email for a price and availability? be very careful of this Lord Valve person, while he knows a fair amount from a technical standpoint, he also has a checkered past of steering folks into the brands of tubes that have the highest profit margin for him, rather than the tubes that have the best tone for the same amount of dough. my recommendation for a source would be Ned Carlson, of Triode Electronics, same tubes that Lord Valve has available, a bit cheaper than LV, and far more important, Ned will recommend tubes based on sound, and not let greed cloud his objectivity. He is also a hilarious, beer swilling, crazy mexican-food-chompin real Chicago old-school guy, reminds me of John Belushi a little bit. And no one has been selling tubes and Dynaco upgrades longer, that I can think of. here is the link to Ned's Triode Electronics site (one of America's largest tube stores and a treasure trove of free technical info) http://store.yahoo.com/triodeel/index.html |
#9
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Yeah, I'll send you a catalog if you request it. (6 catalogs, actually...
one for power tubes, one for rectifier tubes, one for preamp tubes, one for parts, one for Caig Labs doctor juices, and one for QSC amps.) LV Lou deGonzague wrote: LV, I didn't see any links to what you offer or pricing? Or do you email for a price and availability? "Lord Valve" wrote in message ... Jim Stewart wrote: This weekend I rescued a beautiful old Dynaco Stereo 70 amplifier from the dumpster at the recycling center. It's in good shape, but the output EL34's are of all different manufacture. I'd like to get 2 sets of matching pairs for replacement. I take a look on ebay and there's a zillion people selling matched pair EL34's. How do I know that they are truly matched? There's never any statements about how they are matched. For all I know, "matched" means the same manufacturer. On one website I looked at, the writer suggested matched Tesla EL34's for good performance at a reasonable cost. Any opinions on this? Where can I get two pairs? I have what you need. Lord Valve Tone Chaperone VISIT MY WEBSITE: http://www.nebsnow.com/LordValve I specialize in top quality HAND SELECTED NOS and current-production vacuum tubes for guitar and bass amps. Good prices, fast service. QSC amps, RNC compressors, lots of other good stuff! Partial Client List: * Derek Trucks/Allman Brothers Band * * Meatloaf * Catherine Wheel * Yo La Tengo * Let's Go Bowling * * Rob Hyckys (guitarist for Commander Cody) * Waky Amps * * Fleetwood Mac * Tyrin Benoit * Eugene Fodor * Dale Bruning * * Komet Amplification * Dr. Z * Maven Peal * Blockhead Amps * * Jim Kelley * Balls Amplification * Roccaforte Amplifiers * * Gerhart Amplification * Aiken Amplification * The Right Half of AGA * * Lots More * NBS Electronics, 230 South Broadway, Denver, CO 80209-1510 Phone orders/tech support after 1:30 PM Denver time at 303-778-1156 - Our 23rd Year - VISA - MASTERCARD - PAYPAL Philo T. Farnsworth sez, "Vacuum tubes kick major ass. Be a MAN...and buy some TODAY!" |
#10
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Jim Stewart wrote: Lord Valve wrote: Jim Stewart wrote: This weekend I rescued a beautiful old Dynaco Stereo 70 amplifier from the dumpster at the recycling center. It's in good shape, but the output EL34's are of all different manufacture. I'd like to get 2 sets of matching pairs for replacement. I take a look on ebay and there's a zillion people selling matched pair EL34's. How do I know that they are truly matched? There's never any statements about how they are matched. For all I know, "matched" means the same manufacturer. On one website I looked at, the writer suggested matched Tesla EL34's for good performance at a reasonable cost. Any opinions on this? Where can I get two pairs? I have what you need. Maybe you could tell us what equipment you use I built all of it myself. and how you match your tubes Really friggin' close. and how much they cost. Not all that much. Those folks listed in my sigfile know how good they are. If you'd like to hear for yourself, just listen to the radio... there'll be some of mine on in a bit. LV |
#11
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arizona cowboy wrote: "Lou deGonzague" wrote in message ... LV, I didn't see any links to what you offer or pricing? Or do you email for a price and availability? be very careful of this Lord Valve person, while he knows a fair amount from a technical standpoint, he also has a checkered past of steering folks into the brands of tubes that have the highest profit margin for him, rather than the tubes that have the best tone for the same amount of dough. You're a liar. In fact, let's see you prove *anything* you've said.. These folks - Partial Client List: * Derek Trucks/Allman Brothers Band * * Meatloaf * Catherine Wheel * Yo La Tengo * Let's Go Bowling * * Fleetwood Mac * Tyrin Benoit * Eugene Fodor * Roccaforte Amplifiers * *Rob Hykys (guitarist for Commander Cody) * Komet Amplification * Dr. Z * Maven Peal * Blockhead Amps * * Jim Kelley * Balls Amplification * Dale Bruning * * Gerhart Amplfiers * The Right Half of AGA * Lots More * ....would be fairly hard to fool. You, sir, are a dumpster-diver and a know-nothing. Go hustle your moldy **** on e-bay and leave the real stuff to the pros. Lord Valve Expert |
#12
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Wbittle wrote: Hi, I have used Sovtek, Tesla, and Svetlana and all work well. The problem with matched sets is how long they were 'burned in' prior to the final testing stage for matching. What you really want in an ST70 to preserve sonic balance channel to channel is a matched quartet of EL34's. Personally, I'd read the seller's feedback and see what others think of his items. If the seller has mostly all excellent feedback, then chances are he is a pretty square shooter. But if you see a lot of neutrals or negatives, be careful. Also, if this amp was recovered from a dumpster chances are it is in need of an electronic restoration before it will ever sound correct or be reliable. ST70's are great power amps. I have one myself. But my amp is totally refurbished. You would not believe the difference in sound when you change out certain old components which have drifted in value. There is no way to know for sure that tubes balanced with a tester will in fact perform as a matched set in an actual circuit. So, although the set you buy could have been picked, tested and packed as a matched set. That is no guarantee that they will remain that way. I have a set of four EL84's in a Scott 222C that I matched out of 12 tubes and they have remained close for over three years. I have a set of Sovtek 7591's that remained matched for about 3 months of use then drifted apart in value. I had to remove them and recheck them then do my best to pair them off in reasonably matched pairs. There is no way the seller could have known this would happen. BIll B. All tubes drift apart after they have been supplied matched. But the ones that were not matched stay well apart forever, or they only drift together accidently. In the last pair of Quad II amps which I re-furbished, the thd in signal at listening levels could be drastically reduced by swapping the positions of the output tubes and input EF86 around for the lowest measured thd. In one position, thd could be 15 dB higher than the other, mainly 2H. The tubes involved in the samples I refurbished were probably not well matched. With guitar amps, I doubt matching the tubes for the same signal transconductance at the same idle current would make much difference, and I doubt you'd notice it when listening to the radio, as Mr Valve suggests. I haven't a clue how Mr Valve matches his valves, and although he is quick to say he does a great job, he leaves me completely uninformed about how he does it, and I remain very unlikely to go to him for matched tubes. Sure there are lots of musos who like his services, but musos mostly know sweet **** all about technical aspects of their amplifiers, so any muso recommendations can only mean sfa to me. What may be more important for guitar amp tubes is that they have equal idle currents at a given grid voltage. Having equal transconductance does not always mean an equal grid bias voltage will produce the same idle current. A small number of tubes would need the same bias voltage applied, *and* have the same transconductance with signal. If this is the case, these tubes are truly matched. In amps with more than two output tubes, the tubes can be swapped around so the transconductance, Gm, of each 1/2 of the tubes on each side of the PP circuit do total to give very nearly equal Gm for each 1/2, and the thd will then be lowest when the tubes re biased individually for equal idle current. To set up for lowest thd at listening levels for hi-fi amps takes time and patience, and a thd meter and volt meter. Sorry, but its all rather fiddly and difficult. 95% of musos just buy tubes, plug them in and use them. Some bother to adjust the bias, or *balance* the bias via the pot at the back of their amps, and this minimises the hum caused unequal bias currents in a pair of output tubes fed from a PS where there is a lot of hum at the CT, which is a feature of so many guitar amps; they have attrociously noisy PS compared to hi-fi amps. And it was compounded somewhat by the practice of Fender et all to supply export model amps without the LC filter following the resevoir capacitor. But the extra dirty growl caused by the supply hum intermodulating with the guitar notes is all musical to most musos in the world of pop. Musos are rarely if ever satisfied with their amps unless they sound pleasantly distorted, so 10% of mainly 2H and 3H is normal at even low levels, with 40% on strong overdrives, where the signal is mainly a square wave, and the type of tubes don't make much difference. You could have an EL34 and a 6L6 in a PP circuit, and not hear anything spectacularly better or worse during serious over drives. The heavy metal bands, and now dark metal types can only survive on 40% Dn for most of the time, and tube matching is a silly concept of no value whatsoever. But to listen seriously to an old Italian cello being played by a master, better you have well matched tubes, lest the cello sound worse than if you were at the venue where it was recorded. Patrick Turner. |
#13
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Hi,
I have used Sovtek, Tesla, and Svetlana and all work well. The problem with matched sets is how long they were 'burned in' prior to the final testing stage for matching. What you really want in an ST70 to preserve sonic balance channel to channel is a matched quartet of EL34's. Personally, I'd read the seller's feedback and see what others think of his items. If the seller has mostly all excellent feedback, then chances are he is a pretty square shooter. But if you see a lot of neutrals or negatives, be careful. Also, if this amp was recovered from a dumpster chances are it is in need of an electronic restoration before it will ever sound correct or be reliable. ST70's are great power amps. I have one myself. But my amp is totally refurbished. You would not believe the difference in sound when you change out certain old components which have drifted in value. There is no way to know for sure that tubes balanced with a tester will in fact perform as a matched set in an actual circuit. So, although the set you buy could have been picked, tested and packed as a matched set. That is no guarantee that they will remain that way. I have a set of four EL84's in a Scott 222C that I matched out of 12 tubes and they have remained close for over three years. I have a set of Sovtek 7591's that remained matched for about 3 months of use then drifted apart in value. I had to remove them and recheck them then do my best to pair them off in reasonably matched pairs. There is no way the seller could have known this would happen. BIll B. Jim Stewart wrote: This weekend I rescued a beautiful old Dynaco Stereo 70 amplifier from the dumpster at the recycling center. It's in good shape, but the output EL34's are of all different manufacture. I'd like to get 2 sets of matching pairs for replacement. I take a look on ebay and there's a zillion people selling matched pair EL34's. How do I know that they are truly matched? There's never any statements about how they are matched. For all I know, "matched" means the same manufacturer. On one website I looked at, the writer suggested matched Tesla EL34's for good performance at a reasonable cost. Any opinions on this? Where can I get two pairs? |
#14
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"arizona cowboy" wrote in message ... "Lou deGonzague" wrote in message ... LV, I didn't see any links to what you offer or pricing? Or do you email for a price and availability? be very careful of this Lord Valve person, while he knows a fair amount from a technical standpoint, More than a fair amount, I regard him as a valuable resourse to me when I have a problem I can't figure out. I have used his brain once, he helped me immensly. I certainly owe him some sugar free Red-Bull's! he also has a checkered past of steering folks into the brands of tubes that have the highest profit margin for him, rather than the tubes that have the best tone for the same amount of dough. Fisrt off he can balance tone and longevity, these amps get the hell beat out of them, I've repaired my fair share of geetar amps in my time as a bench tech. I am 100% with him on his reccomendations on RELIABLE tubes. Profit margin..... I like my profit margin too, believe it or not; this fat boy's gotta eat, pay mortgage, run a shop, and buy toys. Have you lost your knowledge of American commerce? It's Walmart/internet assholes of the world that ruin face to face trade and customer service. If I buy a ****load of tubes because I got a deal do you think I'm giving you a discount? Hell No! It's my ability to buy a ****load that allows me to make money off of you. If you want a deal, go get a dealer account, tax number, etc and buy your own ****load and let the unused rot away. I don't care because there are of plenty of geetar players who do buy them off the internet, "repair" them theirselves, screw them up worse, and bring them to me. Wola I just made more money and sold another set of tubes because the dip**** doesn't know what a bias resistor is. my recommendation for a source would be Ned Carlson, of Triode Electronics, Yep he'e a great guy, close to me geographicaly. same tubes that Lord Valve has available, a bit cheaper than LV, and far more important, Ned will recommend tubes based on sound, and not let greed cloud his objectivity. How 'bout ones that sound good and can get slammed in and out of a entend-o-van nightly and still fire up 5 min before showtime, Remember some of our customers make money off the reliablility of their gear, our reputation of reliability allows us to make more money because the customer is buying "insurance". He is also a hilarious, beer swilling, crazy mexican-food-chompin real Chicago old-school guy, reminds me of John Belushi a little bit. And no one has been selling tubes and Dynaco upgrades longer, that I can think of. I would imagine there are more people out there making money off their Ampegs, Marshalls, Leslies, and Fenders than for Dynaco owners. I enjoyed the rare Dynaco in the shop. But my bread and butter was from the PROFESSIONALS. here is the link to Ned's Triode Electronics site (one of America's largest tube stores and a treasure trove of free technical info) http://store.yahoo.com/triodeel/index.html I'm not putting Ned down, BUT there is no reason to put LV down due to his business practices. They are legit and I would feel very comfortable (I have) using his advice and BUYING from him after I got the advice! I have referred many of my touring customers to him in times of need. Chad |
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