davidsss Posted September 9, 2012 Posted September 9, 2012 (edited) I am thinking of replacing my valves, been getting a few strange noises, and I'm after some opinions. My amp is a Melody I34R and it runs 4 x 6SN7 valves and 4 x EL34 valves. It also has a 101D rectifier but that shouldn't need replacing. First questions on valve numbers. Are 6CA7 valves a direct replacement for EL34 or should I check with my amp manufacturer? How about the 6CA7-T? What about KT77s, are they interchangeable? With 6SN7 valves, what does it mean when it says 6SN7GT and are they interchangeable? Are CV181 or CV181-T interchangeable or should I check with my manufacturer? I went back and read the Shuguang Treasure thread and found varying opinions. What do people think of the Treasures and the later released Psvane valves? The TJ Full Music valves get good raps. Anyone know a good supplier for these (I know they come under a few different brand names) and which of their valves would be best? Just looking for some subjective opinions and links to good suppliers. Thanks DS Edited September 9, 2012 by davidsss
GraemeB Posted September 9, 2012 Posted September 9, 2012 davidss, I've recently upgraded to a matched pair of Sophia 6SN7 tubes in my ModWright LS100 pre-amp. Very impressed now they are starting to run-in. These were recommended upgrades by Dan Wright who made the pre-amp. Well worth the money for the sound improvement so far.
RoHo Posted September 9, 2012 Posted September 9, 2012 Hi David, 6CA7 and KT77 are both equivalent to the EL34. They are designed to be interchangeable and any will work with no problems in an EL34 amp. Psvane add the "T" on to their 6CA7 as a marketing thing, I assume. With most valves as they were further developed extra letters were added to distinguish these later versions. Often this indicated that the valves had some maximum ratings incrementally increased due to better manufacturing/materials. The operating conditions stayed identical. So the 6SN7 time line went 6SN7, 6SN7GT, 6SN7GTA, 6SN7GTB. Any will work fine in your amp. CV181 is a "near equivalent" to the 6SN7. That means it will most probably work in a 6SN7 circuit but the operating conditions will be slightly different TO WHAT THE DESIGNER INTENDED. Maybe it will sound different or better, maybe it won't. I have banged on about this before but it does annoy me when people with little technical knowledge encourage substituting in (obscure, expensive) valves with different operating conditions for the common 6922/E88CC or 6SN7. Check with the manufacturer. You're right that it's difficult to get a handle on the quality of these "premium" Chinese valves. Their marketing and retailing style is confusing, the QA is questionable and all that gets mixed up with good old anti-Chinese sentiment. I really don't know. I have heard good things about some of the Treasure valves and "Goodcomponent.com" has been recommended over at AudioAsylum. They certainly are cheaper than the main Western retailers. DIY Hifi Supply sell TJ valves and have been recommended here several times. Rod
Upfront Posted September 9, 2012 Posted September 9, 2012 +1 for the sophia. Even the wife noticed the difference between these and the stock Chinese
Bronal Posted September 10, 2012 Posted September 10, 2012 Have a look at this site: http://www.audiotubes.com/ This is the site of Brent Jessee, a well-known and reputable dealer in (mainly) NOS valves. You will see he describes the distinction between various types (eg the 6SN7 range) and variants.
pulinap Posted September 10, 2012 Posted September 10, 2012 (edited) If you are after NOS 6SN& I recommend Kenrad VT231 and Russian 1578 (hole plate). I use them in my Melody preamp. However, Marconi Osram B65 is the king....... if you can afford them. BTW, you can borrow couple from me if you wish....(well not the B65s) Edited September 10, 2012 by pulinap
Braddles 63 Posted September 10, 2012 Posted September 10, 2012 Pm Stevenvalve. He has some good stuff.
GraemeB Posted September 10, 2012 Posted September 10, 2012 If you are after NOS 6SN& I recommend Kenrad VT231 and Russian 1578 (hole plate). I use them in my Melody preamp.However, Marconi Osram B65 is the king....... if you can afford them. BTW, you can borrow couple from me if you wish....(well not the B65s) You're not kidding! Found these just now: http://www.tejastubes.com/NOSMarconiOsramB65MetalBase.htm I think I'll stick to my new Sophias
pulinap Posted September 10, 2012 Posted September 10, 2012 (edited) You're not kidding! Found these just now: http://www.tejastube...65MetalBase.htm I think I'll stick to my new Sophias Marcon/Osram B65 is the KING, hence the need for a King's ransom to purchase them..... :D However, I've seen pairs going under 500 USD Edited September 11, 2012 by pulinap
davidsss Posted September 11, 2012 Author Posted September 11, 2012 (edited) Hi David, 6CA7 and KT77 are both equivalent to the EL34. They are designed to be interchangeable and any will work with no problems in an EL34 amp. Psvane add the "T" on to their 6CA7 as a marketing thing, I assume. With most valves as they were further developed extra letters were added to distinguish these later versions. Often this indicated that the valves had some maximum ratings incrementally increased due to better manufacturing/materials. The operating conditions stayed identical. So the 6SN7 time line went 6SN7, 6SN7GT, 6SN7GTA, 6SN7GTB. Any will work fine in your amp. CV181 is a "near equivalent" to the 6SN7. That means it will most probably work in a 6SN7 circuit but the operating conditions will be slightly different TO WHAT THE DESIGNER INTENDED. Maybe it will sound different or better, maybe it won't. I have banged on about this before but it does annoy me when people with little technical knowledge encourage substituting in (obscure, expensive) valves with different operating conditions for the common 6922/E88CC or 6SN7. Check with the manufacturer. You're right that it's difficult to get a handle on the quality of these "premium" Chinese valves. Their marketing and retailing style is confusing, the QA is questionable and all that gets mixed up with good old anti-Chinese sentiment. I really don't know. I have heard good things about some of the Treasure valves and "Goodcomponent.com" has been recommended over at AudioAsylum. They certainly are cheaper than the main Western retailers. DIY Hifi Supply sell TJ valves and have been recommended here several times. Rod My post from last night appears to have disappeared! Anyway, thanks for the detailed advice RoHo, very useful and precisely what I was looking for. Looks like the 6CA7s and KT77s would be fine but I'll steer clear of the CV181s I think. Looks like I can get 6SN7 equivalents in the TJ valves but not EL34 equivalents, does that sound correct? Keep the info coming and thanks for all the replies. DS Edited September 11, 2012 by davidsss
RoHo Posted September 11, 2012 Posted September 11, 2012 Looks like I can get 6SN7 equivalents in the TJ valves but not EL34 equivalents, does that sound correct? Yep
davidsss Posted September 20, 2012 Author Posted September 20, 2012 Has anyone bought from DIY HiFi Supply on EBay? Based in Hong Kong and they have the TJ valves. DS
RoHo Posted September 20, 2012 Posted September 20, 2012 Has anyone bought from DIY HiFi Supply on EBay? Based in Hong Kong and they have the TJ valves. DS Many times, but not through eBay. They have their own site at diyhifisupply.com
at68 Posted September 21, 2012 Posted September 21, 2012 DS I have bought passive components through DIY HiFi supply - no problems. I have an EL34 PP amp, and have tried JJ KT77 and EH 6CA7 valves in replacement. I was not fond of either to be honest. Both seemed to have more grunt, and KT77 produced slightly more highs, 6CA7 slightly more bass. But overall I prefered my Siemens EL34. If I had to pick one to try it would be the winged c EL34. TJ/Sophia valves if I had more $$$ Hey, but thats my opinion so dont shoot me down in flames guys! adam.
davidsss Posted September 21, 2012 Author Posted September 21, 2012 I had winged Cs for a while, quite nice. Not overly impressed with the EHs so I'm looking at the Black Treasures now and TJs for the 6SN7s. Mind you, since I started this thread, no more strange noises. It's like calling the RACV! DS
ehtcom Posted September 21, 2012 Posted September 21, 2012 Hi DS. Be carefull purchasing TJ tubes (also rebranded as Sophia) I purchase the TJ 6SN7 and 6SL7 in lots or twenty, I get 3 or 4 faulty from each batch. Might be best if you purchase them from someone who has soak tested and matched them up. The 101D isn't a rectifiying tube, it is actually a small signal amplifying tube where low amounts of power are needed. I think Melody use it as a voltage regulator for the 6SN7's supply rail. The Electro Harmonix 6CA7 are worth a look Also, good to play with some old stock 6SN7's, from time to time you can pick up tested quads of old stock 6sn7's on US eBay. Usually a lot cheaper and much better built than the new production stuff. http://www.ebay.com.au/itm/4-NIB-GE-6SN7GTB-Tubes-USA-Side-getter-Quad-2-/130740285007?pt=Vintage_Electronics_R2&hash=item1e70ba6e4f http://www.ebay.com.au/sch/i.html?LH_AvailTo=15&_nkw=6sn7+quad&_arm=1&_armm=63&_ruu=http%3A%2F%2Fwww.ebay.com.au%2Fsch%2Fi.html%3F_nkw%3D6sn7%2Bquad%26_arr%3D1&_rdc=1 Cheers, Earle.
davidsss Posted September 21, 2012 Author Posted September 21, 2012 Thanks Earle, I'll check the DIY HiFi Supply site and see what they do. Yeah, not totally sure where the 101D comes in, then again, not sure how the whole thing works anyway! I have been wondering if I should get a spare 101D just in case it goes one day. DS
soundfan Posted September 21, 2012 Posted September 21, 2012 The bligh of tube amps. Noisy tubes. I've been lucky in the past with 300B and EL34/6CA7 tubes, but with driver and rectifier tubes I've purchased quads/trios/pairs etc in the past that have suffered from this problem. And where possible I always buy matched. But having said that, I've always been a fan of NOS tubes over current production tubes, maybe some of the blame lies there. It's a bugger when your tube pre uses 8 tubes and having to try to identify a noisy tube.
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