Don't think New Sensor has our back

[pbman1953]

I was given the suggestion to post about my situation with New Sensor.


About a year ago I bout a quartet of TungSol KT-120's and bought them from Doug's Tubes. I've bought from him before. This is the first time I've had an issue with any tube I've ever bought, lucky for me right? Thanks to the forum I modified my Traynor YBA-3 Custom Special from a stock EL 34 amp to a 6550 usage. I tried 6550's for after a while but decided to go , after extensive research and questioning,  for a quartet of Kt-120's. I even reached out to Traynor and told them what I was doing. They told me that what I modified was fine and to check that the transformers didn't get hot to touch.
I told Doug that the tubes would be used in Traynor Bass amp and at that time he did not sway me away from using them.


I have to state that a few things-


1) I use this amp twice month for 3 hours. Then possibly 2-3 gigs at 2 hours each. so over all- 100 hours +-.


2) I use a Bias Rite and typically set tubes up from 60% and a max of 65% depending how close the tubes test.


3) I play classic rock and blues, nothing more. I use a 4 ohm (2 x 15) cab which is the suggested rating for this amp. With the 2-15's the transformers and are room temp at best, after 3 hours.




Back to the story, I noticed recently that the tubes have been noisy. Noisy in the sense that I tapped the can and I heard noises through the system. Think of it when tap preamp tubes, but from a larger bottle.


So I think I have 4- microphonic KT-120's and I reached out to Doug and I was told, sorry 90 day warranty. The he goes to tell me, after he knows that I was using in a tube bass amp, that they would be better suited for HiFi. Why didn't he tell me then? I would saved $200 and bought a different tube. The I decided to reach out to New Sensor and all I got back was sorry, 90 day warranty. The sad part is they sound great.


I figured since thy owned all these tubes that they would step up to the plate and stand behind their tubes. I've learned a lot about companies and warrantees. For example, Michael at Eurotubes warrantee's his tubes not for 90 days, but 6 months. He does extensive testing and does get maybe $5 more than most for the JJ's , but he gives you 6 months and sill will work with you.




So here's a question, I want to send these tubes to a totally independent shop or tech than can test my KT's.  Preferably, I'd like someone that is not affiliated with any tube company. I want a non- biased opinion.




Sorry for the rant and thanks for always be the best help!

[sluckey]

Sorry to hear, but you can't possibly blame New Sensor or Doug's Tubes for tube failure after the warranty period has expired. Venting may help you feel better but it ain't gonna get you a new set of tubes. Why do you want to run expensive overkill tubes in an amp designed to run EL34s?

[pbman1953]

You're right about the warranty but the sound of the 6550's or KT's were so much better. You'd be surprised that responses I got back about using the 120's were very positive. Not just from our forum members.

[sluckey]

Just a couple days ago you started a thread "need help tweaking a bias circuit".

     http://el34world.com/Forum/index.php?topic=20659.0

That thread indicated to me that the 120s were running very hot and you could not bring the current down.

[pbman1953]

Yes and no. I wanted to install a panel mount bias pot. The value of the new one had a different value. I never ran them hot and I wouldn't of ran the amp until correct.




Before I replaced,  bias was fine. 

[HotBluePlates]

... I noticed recently that the tubes have been noisy. Noisy in the sense that I tapped the can and I heard noises through the system. Think of it when tap preamp tubes, but from a larger bottle.

So I think I have 4- microphonic KT-120's ...

The tubes/amp works fine except when you tap on the glass? I'm not sure that's a problem, as most tubes I've ever had will make some kind of sound if you tap on them. Many capacitors will, too.

More often, microphonics in an output tube or rectifier manifest as either a rattle (sounds like something in the room is buzzing, even after **everything** is removed or secured) or a buzzing which sounds like a blown speaker.

Or maybe you weren't able to convey what the issue was with the KT-120's...

... the sound of the 6550's or KT's were so much better. You'd be surprised that responses I got back about using the 120's were very positive. Not just from our forum members.

I have no experience with the KT-120's; maybe Ed Chambley or others do.

I have seen on another forum where the amp discussion board was just an exhibition of consumerism ("Look at my New Amp!" or "This Brand/Model is the Best Ever!") and lacked much of any technical consideration. While probably not the same place you had visited, had you gone to that other forum I imagine you'd have gotten enthusiastic concurrence to use KT-120's and then "told you so" disapproval when they malfunction in your amp. I usually see more straight-shooting tech help on this forum.

[pbman1953]

I agree about the noise.


Plus, If I was told from the start  that they are better suited for HiFi, I would of thought about more before I either bought or went for a set of 6550's.


Don't come back to me after the fact. That's what bugs me the most.






As far as help,  I've learned that this is the only place to be.

[Ed_Chambley]

Hey guys, yes I do have some experience with KT120's, but remember I am running a UL Tranny which does not run screens as hard.  I have worked with a couple of others changing to KT120's.


The first set I got were from Tube Depot and when I installed them they were far from being matched.  They told me they only matched up to 400VDC.  They took them back and refunded, so I lost shipping.  That's cool.


After which I purchased a pair from Upscale Audio.  And then another pair.  I have a friend who has been running them in a Guitar amp almost every night for over 2 years.  Again, same amp design.


I do agree that if a tube dealer states after the fact that these are designed and work better in HiFi after selling them for guitar is wrong.  I personally use my amp a lot for 4 string Bass as well a guitar and love, love, love this amp.  Strong, powerful and with tons of grunt.  Just the thing for old English blues like Free.


In speaking with Kevin at Upscale Audio prior to getting any, I told him what I was using them in and he said they should be able to run in any amp that has a beefy enough PT to handle them and the output section can be guitar amp design.


IOW, you can replace your KT88's in a Marshall Major according to him and he will sell and warranty them for this use.  Still there is a time limit simply because no one really knows how you are running tubes.


Said another way, I toast tubes quite often.  Mainly 6V6 and I do it sometimes knowing they may not be able to handle what I am throwing at them, but you can bet these are not the best 6V6 tubes.  I would never push a nice new old RCA or Tung-sol, but I will push a new production simply to find the limitations.


The KT120 is a great sounding tube and I personally have had positive experiences using them and I have never even tried them in a HiFi.  Maybe I will.

[Willabe]

The only reason I can think off why he would say their better off in a HiFi is maybe he thinks their on the fragile side. But that would be because of how their being made, including their vacuum and with what materials.

A new tube should be able to handle audio in a guitar/bass amp just as well as in a HiFi if their made right with guilty materials. As long as you don't exceed their specs.

For the most part we know by reported experience that new manufacture tubes are not as robust as NOS tubes.

But that's still better than no newly manufactured tubes.       

[sluckey]

Plus, If I was told from the start  that they are better suited for HiFi, I would of thought about more before I either bought or went for a set of 6550's.

Don't come back to me after the fact. That's what bugs me the most.

But jjasilli did tell you back in February they were usually for hi-fi.

I think the only choice is to try.  KT-120 is usually for hi-fi, so there's probably little practical experience here.  Re guitar amps, except for the Reply above, I've only heard of them being used in the Fender 400-PS, where they seem capable of taking the voltage-current abuse offered by the vintage GE 6550's.  See, http://timeelect.com/400-histy.htm


Nothing wrong with tube rolling.  Also note, they draw more heater current, so check for adequate heater voltage.

[pbman1953]

Ok, I'll concede to not remembering the suggestion from jjasilli.  But Doug should of told me , right off the bat, that the tube was better suited for a different use. Not after I complained. I told him up front, what it was for, and he backtracked . Possibly after my sale others he had issues too so he resorted to suggesting only for HI Fi.


Plus this amp was hardly ever moved and had some kind of padding under it.




Can anyone suggest a tube tester to send them to?

[drew]

Doug is not your daddy or your life coach.  Doug is a tube vendor.  Doug sold you the tubes you told him you wanted. Doug isn't going to give you new tubes for free because he has no way of knowing how the tubes have been used or abused over the course of a full year, and 90 days is all the commercially realistic warranty he can offer. 

[PRR]

> Noisy in the sense that I tapped the can....

Can? Bottle?

> and I heard noises through the system. Think of it when tap preamp tubes, but from a larger bottle.

Microphonics in a HIGH level tube is unusual, but can happen, and not be a problem. In fact a Power tube can't be built "tight" since plate heat expands all the spacers and if too tight something would crush or break.

Path I would be thinking--

Do the EL34s do it?

Is it actually the tube, or the socket (bad contacts and joints), or other parts getting shook by bottle tap?

Yes, it can be about impossible to tell. Like finding the rattle(s!) in the dashboard of my 1996 minivan. Can't narrow-down the rattle spot.

Warranties..... well, tubes are not what they used to be, because we all want "a good price" (the amp makers are the worst). On the "hamburger, beer, gasoline, rent" price index, tubes are considerable cheaper now than they were in 1972. Manufacturing quality and warranty costs affect the retail price a lot. As you noted, longer warranty costs more. Radio Shack used to have "lifetime warranty" tubes, which did cost some more than Fred's TV charged. RS really would exchange the tube forever (until they shut the tube business); the tubes were ordinary with "gold" pins and I suspect RS lost bucks on some sales.

Yes, the KT120 didn't exist in 1972 and they do charge a beastly lot for it. And the market for KT120 knows "something" about tubes. You'd think it would be well-made.

But tube sales are annoying to the seller. A lot of customers WILL complain, some for no good reason. The Warranty Period you pay-for sort of limits how much user-complaint a seller can afford to take.

[pbman1953]

Ok, I seem outnumbered and can see there are some Doug supporters out there. I understand that and I get it.


Let's put this in a different perspective but similar in the end.




I used to be in the leather business and I was selling leather for many different uses. I would ask the customer what the leather would be used for (bass guitar amp)  and I would suggest and talk about what would work for them.   If they asked me about another leather and I saw a red flag about using that leather for the use questioned about (using the KT120 in a bass amp) I'd bring it to their attention it right away.  You take care of any possible issue right away so they don't call back telling that they I sold the wrong type of leather.

[xm52]

If you want to have your KT-120 tubes tested, contact tctubes.com. They will test your tubes at the plate, screen, and bias voltage of your amp. This is important to do. They describe how they test and match tubes on their web site.


I wish all tube sellers tested to their standards.

[pbman1953]

Thanks, but I was wondering if there testers out there that have no affiliations. Don't sell.


If there are anyone.

[HotBluePlates]

Ok, I seem outnumbered and can see there are some Doug supporters out there. I understand that and I get it.

I've never even heard of "Doug's Tubes" before. So I have no particular loyalty there.

I mainly wondered if there is a problem here at all, just because your description was vague. But also because I've found over time the issue of "microphonic tube" is itself ill-defined. When I started out with tube amps, I'd read the same thing you describe: "If you tap on the tube and noise comes through the speaker, the tube is microphonic." Then I noticed that every tube I tapped looking for the "bad microphonic ones" produced some kind of thump in the speaker.

Sometime between 2004-2006 I ran into my first truly microphonic tubes: When installed in an amp and the amp was powered-on, I got an instant loud howl. If I turned the volume low enough, the howl stopped. It sounded a lot like a wrong-phase OT with negative (now positive) feedback, except this was a vintage amp which never had any issues. If I did keep the volume low enough to prevent immediate self-howl and tapped lightly with a pencil, I heard a sustained ringing of several seconds at the same howl-pitch, trying to build up into a sustained howl.

It turned out all 5 of the tubes I had exhibited the same behavior, where any other 12AX7/12AY7 I had was fine. In my case, I was using some cheaply-acquired NOS tubes of an unusual type as a 12AY7 replacement. My error was that I didn't note this particular type was developed for use in vacuum tube computers... Its expected mode of operation was full-on or full-off (and solidly controlled by applied grid voltage). Therefore, microphonics were no issue in its intended use, and the manufacturer took no special care in build or testing them to eliminate microphonic tubes.

That was eye-opening. Suddenly, if a tube didn't howl, ring or rattle when I played through the amp, it was "non-microphonic enough" for the intended use. And whether a tube seems microphonic or not can be critically-dependent on the specific application it is used in...

So from my perspective, I'm unsure still if there is really a defect, but only because I don't know exactly what you're describing. I think it's unfortunate the warranty period has expired. I think if you're truly unsatisfied with how Doug's Tubes has handled the issue you have every right to tell others you're unhappy with them and refuse to buy from them in the future.

[PRR]

> I seem outnumbered

No, we hear you, but in today's world you only get "so much" pre- and post-sale support.

Also "noise when tapped" kinda goes with how tubes are made and work. They are thin bits of sheet and wire with minimal support. All tubes are microphonic to some degree. To say "fault" you should say why this is A Problem so severe the tube can not be used in the usual applications for such tube.

I do NOT think "KT-120 is for Hi-Fi". Tubes is tubes and usually don't care what you do with them. (Within ratings; but KT-120 ratings are far higher than EL-34.) Frankly I don't think they had any specific goal in mind. I think they said "Hey, we can put more plate-metal in this bottle and sell it for a higher price!" The actual upgrade includes more heater. I know that grid-windings are run-off by the yard and then sliced into short pieces for tubes. They may have done the same thing for all elements: longer plate, longer grids, longer cathode-heater. Where a KT-88 is a 2-inch "cut of tube", KT-120 may be a 2.5" cut.

[pbman1953]

The problem exists even withe volume all the way down.


As far as buying from Doug, I probably won't buy any expensive tubes there anymore.

[PRR]

> The problem exists even withe volume all the way down.

HBP's problems were in preamp tubes, before the volume control.

There's no volume control after a power tube, so volume should not affect it.

> As far as buying from Doug

Just to be clear: Doug's Tubes is a tube-only shop in NY.

The host of this forum is also named Doug, and runs a web-shop for all sorts of guitar amp parts. Took a moment to realize you do not mean him! I know, because he does not sell KT-120, and stopped selling even 6550.

[pbman1953]

http://www.dougstubes.com/

[sluckey]

I do NOT think "KT-120 is for Hi-Fi". Tubes is tubes and usually don't care what you do with them

That's my thinking too. The difference is the users and abusers. Hi-Fi guys tend to be more conservative with tubes, striving for max fidelity and not so much interested in max power. And definitely not interested in distortion, growl, coloration. OTOH, guitar folks tend to push tubes way past the redline. They are very likely to abuse a tube by constantly tinkering with bias and other factors in an effort to get "THE SOUND" that's in their head.

[pbman1953]

I'm the HiFi guy who plays bass.  In the 80's I was a manager of a high end care audio company . No boom  cars here, true HiFi in the car. I know what distortion sounds lIke and can sense a system at it's limit. I'm always in search of a full bodied sound.

[Ritchie200]

Unless I missed something, you stated that " I noticed recently that the tubes have been noisy. Noisy in the sense that I tapped the can and I heard noises through the system".  As has been stated, components and tubes will make noise when up and running if you beat on them.  Could they have been doing this since day one?  Is this also happening when you are playing?  When you hit a certain note or string?  If the head is sitting on the cabinet or a chair next to it?  You didn't mention specifics.  If it is not evident when playing, I don't see the issue?  Your lucky you got 90 days.  I spent a LOT of money with groove-your-wallet tubes and I didn't even get a tshirt when I tried to return their crap.

As Ed mentioned and you as well - this is an awesome sounding tube and he has been flogging them for a while now.  I know several Major owners with the original screen setup that have also been running them for years.  So we are talking screen voltage north of 600v along with all the other HV issues this amp has.  Plate voltage is north of 600v as well.  This is a robust tube and as PRR said, that tube doesn't care where you plug it in.

Jim

[pbman1953]

I noticed the issue when I had the amp on while working out a hum that Ed was helping me with.  This goes back to last month. I was very close to the amp sitting on a chair at almost ear level to the speaker. I'm not sure if this was from day one. It was noticed whIle I was probing the amp for a possible bad connection.  While probing I noticed the bottle noise and it ended up being the power tubes.
The amp has also be placed off the cab and the noise is better but the amps own vibrations are picked up from the power tubes. There's a fan behind the tubes plus vibrations from the transformers. And yes everything is screwed tight.

The plate voltage has been an average of 500 volts and current average is 75. Like I mentioned before that this tube did sound great. I have no complaints with the tubes sound quality.

[pbman1953]

I decided to send my tubes out for testing and I sent them off to TC Tubes, thanks to xm52.


I talked to Tyler out there and he sells the KT 120 and seems to know what he's talking about. In the meantime, I borrowed from another amp 4 - JJ 6550's and they sound great. The amp is quiet and honestly I did a spot check on the transformers,too. The power trans was just warmish and the output trans was cold, room temp cold. my volume was at a normal playing setting.

[TheKT88KilledJFK]

I decided to send my tubes out for testing and I sent them off to TC Tubes, thanks to xm52.


I talked to Tyler out there and he sells the KT 120 and seems to know what he's talking about. In the meantime, I borrowed from another amp 4 - JJ 6550's and they sound great. The amp is quiet and honestly I did a spot check on the transformers,too. The power trans was just warmish and the output trans was cold, room temp cold. my volume was at a normal playing setting.

I have various sets of KT88s and 6550s and people say those are for hifi as well.  That's a good thing, because "HIFI" tubes sound the best for bass IMO.  The flat frequency response is needed. 

For what it's worth, I've never had a tube that didn't make noise when you tapped it.

[pbman1953]

You're right about the tapping,but the 120's were more than others. Much more.