KT 170

My amps use KT150's...the new KT170's look interesting. Problem is they are so wide that I doubt I can fit them in the space allotted to the tubes on my amps...which I suspect will be a common problem with these new tubes for a lot of folks! 

I've tried the KT150's and like them. Interested to hear some reviews on these. Anyone know the dimensions of the 170 vs 150?

Here's tube dimensions
https://tubemaze.info/tung-sol-kt170-to-be-introduced/

I'm looking forward to reading user impressions of this big tube.
Perhaps the KT150 turned up a notch in all areas?

I'm super happy with my Ayon KT150 amp.  15 months on same power tubes and I haven't noticed any degradation.  

But it's tantalizing to think about trying this new 170.  Doesn't look much more expensive than the 150!

Interesting, but would any current amps be able to work properly with a KT170?  Simply plugging in a bigger tube doesn’t mean more power.  Most amps can’t maximize a KT120 let alone a KT150’s unless they were designed with those tubes in mind. 

I wonder how many people stick with KT88 (or 6550 or EL34) for the sound over these higher power variants.

It’s for it’s hard for me to imagine the KT170 will be any kind of improvement over the KT150, which sounds perfect to my ears and for my needs

"Interesting, but would any current amps be able to work properly with a KT170?"

Important point.
I haven't confirmed yet, but I'm thinking the upper level line of Prima Luna will accommodate these new bottles, as they do for the KT150.
https://primalunablog.com/2020/10/30/tung-sol-kt170/

I asked Ayon USA about the 170 and they said:

So yes we tested the KT 170’s and as with anything new they are quite unstable. Same thing happened with the 150s when they first came out and over time Tingsol fix them right up.
Our recommendation definitely stay with the 150s.

So, maybe eventually they'll relent.

"So yes we tested the KT 170’s and as with anything new they are quite unstable. Same thing happened with the 150s when they first came out and over time Tingsol fix them right up."

Like many new things introduced, first couple of batches reveals any weakness that might need addressing. I'm going to wait until early adopters report their experience.

I'm highly interested in the 170's for my PL Evo400. Please give us some feedback as soon as these are purchased. 

@tablejockey Upscale doesn't even have them listed for sale yet, which to me seems odd

"Upscale doesn't even have them listed for sale yet, which to me seems odd"

Maybe they haven't got the official "okay" from PL to say it's okay to use on "x" models, along with field history being a new tube?

Call them to get an answer.

Any updates?
I have a pair of newer Quicksilver V4 monos designed for the KT150 and need data sheets on these to see if I can use them

Before you order a set, just be ware the KT-170 bottles are physically too big to fit in any PL amps, and many others. The amp will need to have especially wide socket spacing to allow the 170s to fit. 

johnss-
I imagine PL wouldn’t post this if that were the case
https://primalunablog.com/2020/10/30/tung-sol-kt170/

The KT170 will fit based on dimensions comparing KT 150
http://tungsol.com/tungsol/specs/kt150-tung-sol.pdf#:~:text=KT150,5.57%22%20%28141.5mm%29

https://vacuumtubevalues.com/wp-content/uploads/2021/04/KT170-datasheet.pdf

Pic of KT150 in PL
http://www.tonepublications.com/review/kt150s-for-primalunas-dialogue-hp-integratehttp://tungsol.com/tungsol/specs/kt150-tung-sol.pdf#:~:text=KT150,5.57%22%20%28141.5mm%29

4.5mm on each side(9mm difference) looks like it will be a tight fit, but I looked on my amp, and the front/rear tube spacing looks to be the concern. A call to PL to confirm is in order.

@tablejockey, one step ahead. I did contact PL a month ago asking about the 170s. Response from PL was no dice. 

Good job, johnss.

Saved me from a future $800+ purchase.

I have a Jolida 502A tube amplifier. I have had 6550, KT 88,  KT 120, KT 150 and now the KT 170. Prior to upgrading I would speak with Jared from Jolida, CEO of Black Ice Audio and each time he told me that my amp would be able to handle the upgrades. The KT 170 is a physically larger tube, not much room between tubes. They remind of me of a 300B tube. As to the sound, there is more of everything there, except noise. I find myself not using as much volume as I used to, there is deeper and more natural bass, a wider soundstage and a little cleaner in the highs. I have had them for about 4 months and no problems with the tubes. The other tubes are 12AX7-Mullard reissues and 12AT7 Mullards. I am happy with them. Prior to buying them, I would contact the manufacture of the amp to see if the amp can handle the tubes. I hope this helps some of you.

I've had them for about 400 hours now in a primaluna evo 300 power amp. Not much increase in power (PL is a little to gentle on them, I think they might like to be driven a bit harder) but a discernable increae in control of the speakers (dhalquest dq-20's are behaving very nicely). Best way to describe them is as a GL kt-77 on steroids. Not the ones that make you grow hair, the ones that make you all sexy and stuff. Or something. Just not hairy.

It's very linear and tight with wonderful bass - very SS like in that regard but you won't mistake it for SS - at least not on my system but dayum, is it frigging nice. Very nicely extended highs and a surprisingly pleasing midrange to boot.

I really like it.  

NOS amprex in gain stage and NOS sylvania in driver stages. 

"I've had them for about 400 hours now in a primaluna evo 300 power amp."

Interesting news stickmon. According to johnss, he contacted PL and told they wont fit.

This has my buy now finger twitching.

They hit the xformers on any PL that uses 8 output tubes.

I contacted upscale audio a couple months ago about them: "We’re testing, buy kt-150’s". Screw that, you advertise as "future tube proof" so we’re gonna test. They are :)

EDIT: total cost for the 170's from viva tubes was 20 bucks less than 150's from upscale. Sure, it isn't much but thats 2 good grams of (legal) weed here.

"They hit the xformers on any PL that uses 8 output tubes."

stickmon42-
Is that what Upscale told you? Tubes contacting  the Xformer case seems like a concern. I have the HP=8 

That's from the Facebook PL group, think someone measured and verified with upscale but it wasn't me. I have no way of actually verifying if it's true or not but it would be a major concern. 

All I can say for certain is that they work extremely well in an evo 300 power amp. 

I have less than five hours on a quad of them. I’m thrilled. It’s like having a new system. More lower mids, bass, live music feel. Was using KT-88’s. Speakers are not efficient ones. Got an email from my Amp maker saying he’s now offing them, so no worries in trying. 

Cuss words of joy. To me the lower volumes is where the fuller sound comes out. Loud is loud. By by KT 88’s I have a new love. My wife gave me a perfunctory agreement but that’s suspect. But she stayed for a while asking to hear some of her favourites. 

"It’s like having a new system. More lower mids, bass, live music feel. Was using KT-88’s."

wsrrsw-It's always fun to have that experience with a new addition.
I'm disappointed I can't try them in my amp PL HP. I will contact them directly to get confirmation on what stickmon42 indicated.

Full stop... Have to send back AMP (Roders KWM-88 Integrated Amplifier) to get some changes made inside to use KT170's so as not to damage amp. Went back to 88’s and will dig out shipping box ASAP.

I have 16 KT-170's running safely in my pair of PL Dialogue HP's.  Its just a mater of raising the rear tubes up about 2 -3 inches.  It would be nice if PL made a nice audiophile grade adapter to do this, but $5 socket savers plugged in together does the trick nicely.  The side to side dimensions are just fine. Its the front to back dimensions where you have glass on glass touching.  I crammed them  at first to try them out against the 150's and the sound was everything I liked about the 150's but more so.  Better extension on both ends, better midrange.  I have a small mid bass bump in my setup at the moment and these helped alleviate it somewhat.   The rear KT-170's are raised 3" higher than the front ones and it gives plenty of room for heat dissipation, and they are well away from the front tubes, so no glass on glass.  The socket savers are $20 for 4 on amazon so you need 6 sets of 4 for 24 socket savers  at an additional cost of $120 for the 8 rear tubes.  BTW If anyone is interested in 16 low hour KT-150's (about 300 hrs in a Dialogue HP).  I'm selling them at half price and will include 2 spares I used in my headphone amp.   I have many dresser drawers full of tubes I am not using and need to clean house.  

Brad

Interesting arrangement for the KT 170 to fit, Brad.

Must look quite dramatic with 2 amps in your setup. Bet it sounds great.

As an amplifier designer I can't wait to begin a new prototype. 

All who are upgrading make sure that you don't exceed your power transformer max current on the 6.3 volt buss. These tubes require 3+amps each.  The prospect of a build that will run 800 volts on the plates is awesome.  I will have to build matching transformers that can handle the 300 ma of current going to the b+supply. My current design is a little undersized for the 150s but in testing and a limited production has been reliable. This will be a game changer. I believe still that the best sounding amp I have designed has a pair of soveteck 6l6wxt+........ but we will soon see.