Home » Audio » Thermionic Emissions » New tungsols from SRS tubes and hickock results
New tungsols from SRS tubes and hickock results [message #9222] Sun, 02 October 2005 11:23 Go to next message
Russellc is currently offline  Russellc
Messages: 397
Registered: May 2009
Illuminati (1st Degree)
I recently just could not resist the new very cool looking remake on the tungsol 6650. i have used SED 6550 or SED KT88 previously, but the tungsols are so cool looking I had to have a set. I purchased a quad from a well respected dealer of this brand (SRS), not just someone selling them. their testing is fairly rigorous, and I have had nothing but straight forward business with them in the past. When the Quad came, they were very well packed with no damage and arrived super quick.
When I put them in my properly working hickock 532. (yes I understand the limitations of vintage testers, even one that tests for dynamic mutual trans conductance or what ever) According to hickock info the settings should result in readings of 7000 gm. I have never had even known good tubes test this strong, usually I get just over 6000 for good ones. My current set of SED 6550 with 15 months on them are still at 6000-5025 on this tester. The tungsols tested like this: Three of them were very close, around 5500. but one was rather droopy, sagging to around 4250, then seeming to hold there, but subsequent test seems to indicate maybe 1/2 a needle width lower, but that may just be a little inherent deviation in testing. Upon contacting SRS they responded very quickly with a long letter which basically outlined their testing procedures and how it is done under more real world "dynamic" conditions that my vintage tester cannot reveal, and to "just plug them in and enjoy" Now I will be the first to admit that vintage tube testers are not the burning bush word on results, but if one (likemyself) uses the same one for years (particularly one that tests for dynamic mutual transconductance) on a limited number of tube types ( that I use myself in my equipment, not for resale) you can get a good sense for those particular tubes. The aforesaid testing I performed and the results I get indicate a "problem" to me with the one tube. the lower read of 5500 likely is a characteristic of the tester, (yes, even thought he SED 6550 tested as strong or stronger 15 months later) but the descrepancy in the testing of the one tube isnt. I have never had a well balanced matched set (properly done) that would show a variation of this sort in one tube only. To be fair, I thought I would inquire as to any that HAVE seen a properly matched se that would measure like this on a dynamic mutual transconductance tester, but still be properly balanced under "dynamic" conditions. While I hope I am wrong and it is possible, I cant help but think this would be an explanation that would always answer any descrepancy actual testing would show. I have had other business with this supplier and with no problems, I just cant bring myself to plug them in and enjo with out more.

Russellc

Re: New tungsols from SRS tubes and hickock results [message #9223 is a reply to message #9222] Sun, 02 October 2005 13:56 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18674
Registered: January 2001
Illuminati (33rd Degree)

Seems off to me too. Tube testers basically just power up the tube and bias it into conduction so two that are matched should read the same. I don't think the seller sent you a matched pair.


Re: New tungsols from SRS tubes and hickock results [message #9225 is a reply to message #9223] Sun, 02 October 2005 16:42 Go to previous messageGo to next message
Russellc is currently offline  Russellc
Messages: 397
Registered: May 2009
Illuminati (1st Degree)
It is supposed to be a matched quad, and I believe you are right. Frankly, I suspect they are just as the factory sent them, if they had been matched this would have been caught. I have contacted the seller SRS-webstore and told them that despite their explanation, I am seeking replacement and to advise as to return procedure. I will let all know how they handle this problem.

Russellc

Re: New tungsols from SRS tubes and hickock results [message #9226 is a reply to message #9225] Sun, 02 October 2005 19:03 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18674
Registered: January 2001
Illuminati (33rd Degree)

Try Aki at BOI Audioworks. I've bought matched tubes from him in the past and they've been dead on. He's even good about sending pentode/triode matches on dual section tubes, where others just want to match one section of the other. Sometimes availability makes this impossible, but it's nice to get it when you can.


Re: New tungsols from SRS tubes and hickock results [message #9230 is a reply to message #9226] Mon, 03 October 2005 07:25 Go to previous messageGo to next message
Russellc is currently offline  Russellc
Messages: 397
Registered: May 2009
Illuminati (1st Degree)
SRS recontacted me telling me to return them so they can "rescreen" them. I will not be accepting any B.S. explanations of how these tubes that three match and one is way off are still somehow "dynamically" balanced. Check out there SRS-webstore, their testing protocal is decribed as very exhaustive, but I wonder with this deal. I will definately be posting SRS's response to this and how they handle this. Previously purchased 6l6 tubes (SED) I got from them were spot on. I've been fooling with tubes a long time, and one drooping this far off is simply not matched to the others, dynamically, or otherwise. Now I am wondering about the overall low out put when compared to my 15 month old stronger testing quad set of SED 6650C. Perhaps I got a quad meant for
for the trash bin, who knows. I was a little taken aback by there response to an obvious problem and denial of the possibility that there extreme testing would allow a faulty tube come through. Like they never had a bad tube before... now they offer to rescreen...no one has said replace yet... will keep you all posted on how this plays out.

Russellc

Re: New tungsols from SRS tubes and hickock results [message #9295 is a reply to message #9230] Sat, 22 October 2005 07:23 Go to previous messageGo to next message
Russellc is currently offline  Russellc
Messages: 397
Registered: May 2009
Illuminati (1st Degree)
I received a refund minus a "restocking fee"...I hope this does not mean they are "reselling" these same tubes. They stated that the tubes were just fine. They also complained about a small tear on one of the boxes, and "writing" ( Gm numbers) on the boxes. All I wanted them to do was replace the one bad tube. Easy for them to say that the tubes are OK, but not send them back so I could verify independently.. So, I paid twice on shipping plus a 15 % restocking fee from a seller who will not admit to having ANY bad tubes. I have since learned from other smaller scale dealers who will stand behind their product as to what the problem is. Their sources only warranty the tubes for short periods which usually expire while the tubes are still in the sellers possession. Also, for refund they must be returned to the factory in russia, and some of the small time dealers simply dont want to mess with it. the good ones eat the problem. Apparently others require their customers to. While your milage may definately vary, this is my tale of doing business (for the last time) with SRS-webstore.

Russellc

Re: New tungsols from SRS tubes and hickock results [message #9482 is a reply to message #9295] Tue, 10 January 2006 21:13 Go to previous message
Bill is currently offline  Bill
Messages: 16
Registered: May 2009
Chancellor
Hmm, I just had a bad experience with this tube deaker SRS still unresolved too. I started doing a search for other opinuons on them and found this thread. In my case I ordered a quad set of Mullard reissue EL34 tubes from their webstore site which turned out to be a big mistake (I should have ordered through ebay for more buyer's protection) Then again in hindsight, I should have never ordered from this guy to begin with.
The sale started out with a 1 month delay in getting my tubes. They are in NY and I am in NYC. The tubes should have arrived in two to three days. Somehow it got lost in the USPS system and I went around in circles waiting for SRS to file a claim for me to get either a refund or replacement tubes. SRS filed a claim (they say) with the USPS and said the rest was up to me to wait for the USPS to contact me. Of course I was in constant contact with my post office manager who who to this day says they never received any communications nor claims and knows nothing about it. The postal manager did say it was out of his hands and would be handled by the postal inspection department. But I never received any letters or calls from the USPS. I did keep complaining with my local post office and they said that they lost it. But then just about a month later, they delivered it to me! SRS in the mean time stopped responding to my emails. Well by then I had put aside my tube amps project, so the tubes sat in the box for another week or so until I finally had the time to set up the amps and try them out.
Well, upon opening the square US Priority box with the mulluard tube boxes well padded inside, I measured the tubes on my top of the line B&K 747B tube tester, 3 of the EL34 tubes measured BAD and one measured good. I thought what the heck? I installed them in my excellent working shape Eico HF-60 monoblock amps and biased them up. I noticed that on one amp the bias balance was acting weird and not able to balance properly. So I tapped lightly on one of the EL34 tubes in the amp to see if the bias voltage would change. Keep in mind, I had the bias voltage in safe operating range with less than 45ma flowing through the tubes... the one bad tube sparked or arced internally and began flashing blue light sparks! I said what the @%$!#>?! They sent me bad tubes. In addition to those three tub es measuring very weak (BAD)in transconductance, that one sparking tube must have had loose grids or screens or something to short out like that with judt a tap on it. I wrote several times back to SRS explaining my dilema but they never answered me back until I wrote one last time saying that I was going to start filing complaints about them and posting to audiophile and tube forums about my bad experience. They answered back saying that I should file another claim with the USPS saying that the tubes were damaged by rough treatment while in the hands of the USPS for one month while they were lost. I highly doubt that the tubes were damaged like this by USPS since they were well packaged with cushioning and double boxed with padding in their own Mullard boxes too. I would recommend avoiding SRS as they refuse to reveal their contact phone number or business address even after asking them many times in all of my emails to them. They also stalled the time out so that the 45 day dispute policy time ran out such that I can no longer dispute it through paypal. So now I will have to hassle with this loss and hope that I can get resolution. Do you all want to go through this headache? Hope not. So don't buy from this small fry mom and pop shop business. They are shady and do not live up to their false advertising on their web-site. Needless to say, I am not happy about this dealer. So buyer beware. I guess they are hit or miss. My purchase missed.

Previous Topic: is ok to put a tube PRE in front of SS amp?
Next Topic: Latest AudioExpress about amp with 6DZ7 output tube?
Goto Forum:
  


Current Time: Tue Apr 16 14:34:24 CDT 2024

Sponsoring Organizations

DIY Audio Projects
DIY Audio Projects
OddWatt Audio
OddWatt Audio
Pi Speakers
Pi Speakers
Prosound Shootout
Prosound Shootout
Smith & Larson Audio
Smith & Larson Audio
Tubes For Amps
TubesForAmps.com

Lone Star Audiofest