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AUDIO FORUMS >> Replacement Tubes >> KT 120 tubes vs EL34 on Tori IV?
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Message started by Guillaume Bougard on 12/31/15 at 19:33:07

Title: KT 120 tubes vs EL34 on Tori IV?
Post by Guillaume Bougard on 12/31/15 at 19:33:07

I keep reading great reviews of the Tungsol KT120 tubes.

Has anyone tried them on the Tori IV amp?

I currently have EL34's and they are nice.

What would I gain / lose with KT120's?

Thanks

Title: Re: KT 120 tubes vs EL34 on Tori IV?
Post by alper_yilmaz on 01/07/16 at 14:04:49

Dear Guillaume,

I have been using KT120's on my Copland push/pull amp instead of 6550's and they are spectacular output tubes with very tight bass, open up top and very airy. They definitely contribute to the soundstage and they are more detailed than most other other tubes I have heard. Among all the output tubes I have listened to so far, KT120's and KT150's are my favorite ones (I might add a nice SV83 to this list!).

Almost a year ago, I wanted to use a pair of KT120's on my SE34I.2+, yet Steve mentioned to me that the SE34 cannot bias KT120's appropriately so they would not perform properly. Even if the tube could be used as a substitute for an EL34 (I am not sure if it could be), it needs to be biased according to the tube specs, and some self-biasing amps designed around one type of tube might not do the merit to the other tube. My Copland is not self-biasing and also it accepts the KT120's in place of the 6550's or KT88's which the amp was originally designed around. With the proper bias setup at 0.45 V, KT120's sound fantastic!

In this case, my advice would be to talk to Steve first before investing in a set of KT120's...

Best,

Alper

Title: Re: KT 120 tubes vs EL34 on Tori IV?
Post by Fireblade on 01/07/16 at 19:45:57

Interesting observation. I have a KT88 SET and have been considering to eventually try the KT120's for those same reasons. Yet, my amp is self-biasing so I will need to ask the builder. I love the KT88's and 6V6's in this amp, especially when paired with the right rectifiers (several of these are readily compatible with both output tubes). I suspect the KT120's will work fine with at least one of those on hand, mostly five-Volt Fullwave types. Thanks for the hint.

Title: Re: KT 120 tubes vs EL34 on Tori IV?
Post by alper_yilmaz on 01/09/16 at 11:07:11

Hi Fireblade,

In my Copland, it turns out that the bias voltage for KT88, 6550 and KT120 is the same. I am not sure what the exact parameter is, but I believe that the amp's power supply should be big enough to handle KT120 as it requires "that" parameter (most probably, current draw) more than KT88 and 6550. I hope Steve chimes in and corrects me, if I am talking gibberish! :)

But if your amp can handle KT120, I am positive that you will love it!

Best,

Alper

Title: Re: KT 120 tubes vs EL34 on Tori IV?
Post by Guillaume Bougard on 01/18/16 at 06:59:28

I had KT120's loaned and tried them. They sound just like the EL34's. Not worth spending the money. When I switch off the amp, I have a small noise almost like a bullet fired from a gun with a silencer) that I didn't have with the EL34.

Title: Re: KT 120 tubes vs EL34 on Tori IV?
Post by Fireblade on 01/18/16 at 10:41:44

Hi guys,

I understand the KT77 is very close to the EL34 and it brings more extended highs and lows than the EL34, so I believe the KT77 is a good replacement / upgrade for the EL34, but I have not tried one yet.

To consider:

KT88 => 6550
KT77 => EL34
KT66 => 6L6G

I have the first one and like it very much, but I'm considering the KT120 also ... I think all of these are great, especially from Genalex (Gold Lion).

Title: Re: KT 120 tubes vs EL34 on Tori IV?
Post by alper_yilmaz on 01/21/16 at 08:42:20

Sorry to hear that Guillaume... I wonder if that is because of the whole biasing issue or not...

But if you are already happy with the EL34 performance, TORII is an amazing amp! I had mkII for quite a few years and I used Mullard EL34s on it, which sounded fantastic! Even though I have never heard, I am sure mkIV is even better.

Best regards,

Alper

Title: Re: KT 120 tubes vs EL34 on Tori IV?
Post by alper_yilmaz on 01/21/16 at 08:46:41

About the KT77, fireblade...

I have tried a pair by Gold Lion on my SE34I.2+ and like you said they extended the lows a bit but I could not tell much difference between the trebles of various EL34s and KT77s. For better bass on that amp, I ended up with Electro-Harmonix 6CA7's. Somehow, no other output tubes made much difference in terms of bass.

Best,

Alper

Title: Re: KT 120 tubes vs EL34 on Tori IV?
Post by Fireblade on 01/21/16 at 21:00:34

You must be right, as I have never tried an EL34 or KT77. I just know from my experience with the KT88 that it increases body and dynamics and also extends frequency extremes without distortion relative to the equivalent (similar) 6550's and the like (also, 6V6, 6L6, etc.). Glad you like the EH 6CA7's.