Anyone try KT150 in Primaluna Dialogue Premium HP

I love my HP. I've had it over a year and have rolled KT120 into it from the EL34. I like both sets. But the EL is more "liquid". The sound is awesome. With the KT120s I like the added power and punch. But it can be a bit fatiguing. It's the midrange glare that I notice most. So I wonder if anyone has rolled KT 150s into it. Does it keep most of the niceness of the EL 34s?  Do the 150s have less of that midrange glare?  

What at are your thoughts if you've tried this?  Maybe Kevin Deal has an opinion?  
Do your homework, and make sure the tube 6.3v heater circuit can take the extra current, as the heater voltage can sag.

As the EL34 take 1.5A each and the KT150 can take 2A each.

So for 4 x EL34 = 6A which the Prima Luna can take.

But 4 x KT150 = 8A you need to confirm if it can take this without any 6.3v voltage sag.

Too much heater voltage sag "can" lead to cathode poisoning, from what I've been told.

Cheers George
I do believe I've read of other people using kt150's in a hp and prima luna even lists the 150 in there tube selection.

George is spot on with the amperage figures and I think the hp would be able to handle the kt150 without any problems.

I don't own a hp but I have found the kt150 tube to be very good,giving the midrange qualities of the el34 and the drive and dynamics of the kt88 and kt120 but with no etch and glare.Most other amps that use the kt88 and or kt120 are'nt able to use the 150 unfortunately they don't have strong enough pwr Supplies.

Best of luck to you,

I currently own a ARC VT-80 and contemplating the switch from my current Tung Sol KT-120 to KT-150 for sometime. 

i am also on waitlist for psvane treasure tubes.

Kenny, what brand of KT-150 you tried? 


I recently replaced the old stock Mullard el34s in my amp with Genalex - Gold Lion KT77 and like them much more in all parameters. First time using anything other than el34s, highly recommended.


I have only used the new production tung sol kt 150,they are the only ones I'm aware of.I'm not sure if your vt-80 can use them.

The gold lion kt77 is just a wonderful tube I have used it in a couple of diff. amps with excellent sound.I have also recommended the gold lion kt77 to several people and they just love it,I have even heard them in a very nicely upgraded restored dynaco st-70.


I’m pretty sure the HP can use the KT150. Ask Upscale Audio as they are the importer. It is a very nice tube as I have some with my Premium (non-HP). Mine aren’t quite broken in but they have a nice midrange, good extension and great bass punch. From my understanding and I am not sure what speaker you have and their characteristics but a slightly warm IC would work very well with the 150’s.

I didn't care for the KT120 with my PL Premium and agree they had a nasty midrange glare and I couldn’t get rid of it no matter what driver or gain tube I used. Otherwise not a bad tube as other manufacturers have used them successfully.

Thanks!  The Primalunas are all able to use KT150s, except the Prologue Classic, I think.  I am certain that the Dialogues can use KT150.  

Sam and KDude, thanks for your comments!  Very helpful!  Interesting that Sam had the same experience I did with the KT120s.  I liked them when I had a PL Dialogue One.  But, I think the HP is just more refined, making the grain more noticeable.  

Keep the thoughts coming!
I noticed the same about the KT-120 tubes in a Rogue Cronus Magnum.  Switching to Svetlana EL34 tubes brought all the magic  without the etch and grain.
I can soundly recommend the move to 150s in the HP...I went from 88s to 120s and noticed the same changes.  I didn't get so much of the fatigue but did hear the harshness / glare at higher volumes.  Great sound but it was there...but not enough to go back to the 88s or 34s.

Then I wanted "more" and after much good advice and reading, popped the $800 or so for 8 150s.  Everything I could find concern with on the 120s were removed...from the second I popped them in.  With burn-in they got even smoother.  Quite simply...I would never go back...I really love this amp with 150s.

The power has always been overkill for my Zu speakers, but they respond so well to high-energy passages that I think it improves the already impressive dynamics even further.

I have the integrated and it's superb, but I didn't realize how phenomenal this amp was until I put a few really good pre-amps in front, and the further improvements were astounding.  Running through the home theater bypass inputs, you still get the phenomenal headphone amp too.  I own a First Watt SIT-2, which is also a phenomenal amp, but the HP with 150s is just slightly better or at least as good in almost every way.  I could only give the slightest nod to micro dynamics to the SIT-2...but this is slight at best.  The HP (with 150s) has even more punch and feels even more like live music...which I know is insanely high praise given how good the SIT-2 is.  However, the HP is only that good with 150s, in my opinion.

There are two downsides to 150s in this amp...the cage doesn't fit on any longer (if that matters), and on a personal level, I do not think they are a sexy-looking tube, so you have to look at them even more with the cage off.  But sound wins over vanity!

I haven't read a post where someone regretted the upgrade for any amp that can take them.  I doubt you will prefer the 120 or 88 sound over them.

Thanks for the insightful post!  Since the OP, I have learned a thing or two, and the most important thing is that this HP Integrated is revealing of anything upstream!  

I started thinking that I may want to replace my heavily modified Jolida JD9 phono preamp.  So, I got three to audition - Project Phono RS, Channel Islands PEQ1, and Musical Surroundings Nova II.  All 3 cost about $1k (MS is open box).  GF and I compared all three to the Jolida JD9.  First thing we both agreed is that the Jolida is outclassed by all three of the others.  Nothing against the JD9, but I think it's too much tube in the mix.  The others are cleaner and clearer across the board, and the Primaluna HP was really making that obvious.  After several hours of comparison, we decided to buy the Musical Surroundings Nova II.  It has the quietest background, best dynamics, and smoothest overall sound.  The other two sounded a bit on the bright side, especially with my 803N speakers.

So, after substituting the Musical Surroundings Nova into the system for a while, I went back to the KT120s, and the glare I noticed before is 95% gone.  I think the Jolida has just a touch of tube "rush" that was being amplified by the HP.  With a quality SS phono preamp, it's much better, and I think the SS preamp just works better in the chain.  I was happy with the JD9 for a long time, but now I realize that it was boosting the highs just a bit too much for my system, and was adding a bit of fuzziness to the upper midrange.  Things are much smoother now, from top to bottom, and the glare I noticed wasn't from the KT120s.

Now, I'm still wondering about the KT150s.  Reading SQLSaviors post makes me want to go for it.  Maybe next month.  There is a guy on ebay (wpc1896) who sells KT150 quads for $275.  So, the set of 8 would be $550.  I recently got other tubes from him.  When one died after two weeks, he sent me a replacement immediately without question.  Highly recommended, and I'll probably end up buying a set from him soon.

Lastly, I have a friend who has a machine shop.  I'm going to ask him if he can make a "lift" for the tube cage so the KT150s fit under the cage.  I'm thinking of a short bar for each side with holes on top and spikes on the bottom.  Or, just a spike with a matching hole on top.  If I can get him to make something like that, should I get extras for others?  Would there be enough interest?  SQLSavior, would 1 inch of extra height be enough?
Yes!  I HIGHLY recommend the KT150s in the Primaluna.  I have the Dialogue HP integrated, and I really liked it with both the stock EL34s and some Tung Sol EL34Bs.  However, my speakers are only 86db sensitivity (Harbeth C7s), so I decided to spring for the KT150s and some NOS Mullards in the preamp section.  The difference was startling. The added power and bass depth was the first thing I noticed, but it's also a surprisingly refined tube.  The midrange is detailed but not harsh at all.  There's a real coherence to the sound from top to bottom.  Of course, the KT150 and Mullard 12au7s are about $1500, so it was a significant investment.  However, as someone else said on a different post about the HP, the KT150s are almost a requirement to get the best out of the amp.

1" is plenty, and you could probably get away with 3/4" or even 1/2".

I've gotten used to my cage being off, and my kids are old enough now not to touch the tubes.  But your idea to lift it is a good one.
Thank you!  I'm heading to my buddy's place this weekend.  I'll see if he can help me make some sort of 1 inch riser for it.  We will see how it goes!
I'm running KT-120s, not 150's. The 120s fit inside the stock tube cage, no problem.

I wish folk reporting their sonic observations with these amps would also indicate whether they were running triode, or ultralinear. I run mine in triode, and hear no midrange glare. I find ultralinear to be distinctly inferior to my ears, but it's easy to be fooled by its greater output. When I switch from triode to UL, it sounds louder and clearer, but that is just the increase in volume talking. In reality, it is thinner and less rich in tone.
"I wish folk reporting their sonic observations with these amps would also indicate whether they were running triode, or ultralinear."

sqsavior-having heard the HP/150 in a couple of systems, and a fellow owner NOT using them, IMO the KT150 follows what other types do, when switching UL/triode, still has its unique "punch" for lack of a better term.

As mentioned in a different thread, they just give a little "more" of everything. Of course in the end, it ends up being what our own ears find pleasant.

Im not compelled yet, to give the KT150's a spin. My current 2 year old setup of 6L6's still keep me entertained. Looking at bigger gains here, with a leap in a bigger retail  price point in speakers. Current one are nearing 7 years and I think upgrade bug  has bitten. 

I see some owners here have 10k+ boxes with their HP. No doubt the HP easily serves them. My budget is only half, but Ive got a few candidates in mind. 

I was totally a triode-mode guy for the first 18 or so months of the 150s.  I updated my cabling all around the system to Audience SX (from SE), and I put a really clean pre-amp in front.  After that (I think it was the combo), I preferred ultra-linear.  I think all the things that ulta-linear wasn't as great at before was now totally an improvement and more "live" sounding.  Triode still sounds fantastic, but ultra-linear is just a little more "there."

If you are loving your 120s and don't feel like anything is missing, then I wouldn't touch a thing.  For me, the 150s were just a little bit "more" of the same...more scale for my smallish room.
I realize that this is an older thread but as I found myself today asking the same question as the OP, I thought I should chime in FWIW. I (too) have the DiaLogue P-HP amp (and DiaLogue P-preamp) hooked to Spatial M3 Triode Masters which in combination seem to be a bit lacking in the deep/articulate bass department (with five months of break-in). So I sprung for a set of eight 150s that will arrive this Friday (May 4). I’ll report back on my findings comparing the 150s to the stock EL34s. I had previously tried KT-120s but found them to be too abrasive for my tastes. Hopefully the 150s will bring the bass, retain the mid-range, and avoid the "120 harshness". If not, then I’m off to look at subs.
Strike that last comment: "I’m off to look at subs." I meant to say, I’m off to look at other speaker alternatives.
I think you will find the KT150's midrange will sound much better than the KT120. As far as bass the KT120 didn't have bad bass at all but like you are experiencing it had an annoying harshness I could never tame.   

I have KT150's in PL Dialogue Premium HP mono-block amps driving my Magnepan 20.7's and they work and sound amazing.


would partially agree with samzx12, the KT150s have a nice midrange, but that all changes if you replace the stock coupling caps. Put in some copper foil caps and the KT-120s lose any harshness they have.

but with copper foil caps, my fav tube in the HP  is the PSVANE gray glass KT88s...Open and extended, but super musical midrange with no harshness.

I did end up with a set of KT150s.  And, I traded the Musical Surroundings and went with the Manley Chinook phono preamp.  

This is a truly magical combination.  The sound is full, rich, even FR, and it all really works well together.  I've never heard my system sound so good... and not sure I've heard any system sound better.  The KT150s are great, with the best of EL34, plus the power they lack.  I moved the EL34s and KT120s in and out to try options.  But, since I got the KT 150s, I've stuck with them and have no desire to roll any more.

For the KT150s to fit with the cage, my buddy made a set of aluminum "stands".  They have a pin on the bottom, a hole on the top, and are about 1/2 to 3/4 inch tall.  I put a rubber o-ring top and bottom to keep it from scratching, and it works perfectly!  
I don't post much at all here but wanted to express my opinion on the KT150 tubes I just purchased. Quite frankly, it's the best all around tube I have used yet in my PrimaLuna Prologue Premium integrated amp. Besides the stock tubes, which were OK to start with, I have tried EL34L's, KT77's and KT88's from JJ and thought they were decent tubes but all of them had something I didn't care for, mostly I didn't care for their tone in the upper frequencies. My favorites before the KT150's have been the SED Winged C EL34's and the Siemens RFT EL34's. Both of those are great tubes and I will be keeping them around for future use. Then I got curious to try the KT150's. Glad I did. They don't have quite as nice of mid-range as the previous 2 tubes but they are very well balanced from top to bottom and wow, the bottom end is fantastic. The treble can be slightly etched but just on recordings that sound that way with most any tube or amp. Overall I would recommend trying the KT150 without hesitation. Oh, I should mention that the input tubes I'm using are Telefunken and the driver tubes RCA Clear Tops, both of which I purchased from Brent Jesse, great guy to deal with. The PrimaLuna amp is the first one I have owned from this company and it's really a fantastic product. I can see myself moving up to a Dialogue someday. Speakers are GoldenEar Trition One's which are great too. I'm a very happy camper.
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This is a tough thread to read. Just bought the Premium Dialogue HP integrated and already I'm looking at spending another 800 or so on KT150's... I will try it with the stock EL34s and see how they do. It sounds like everyone is reporting a sizeable upgrade with the KT150's though. 
Yes, I am still very happy with the KT150s.  They increase the bass response, and the power they have helps deliver very tight, fast bass.  Plus all the good midrange that the EL34s gave as well.  Great all around tube!  Highly recommended.

As to the $800, yes it's a big one.  I found mine on eBay from vendor wpc1896.  I paid under $600 shipped.  If it's allowed, here is a link to his post for $271 for a quad with free shipping.  That'll get you a set of 8 for about $550. 

By the way, I think it depends on your speakers.  If they don't have a lot of bass, you may not notice the upgrade to KT150s.  I have full range Revel F208 and I notice for sure.
I am using KT150s in my HP mono-blocks. I have been running almost exclusively in triode mode. My speakers are Wilson Audio Sabrinas. No lack of bass or definition. I'm always amazed at how "real" everything sounds. Puts a smile on my face every time. 
Yep, I completely agree about the Primaluna "smile-itis".  Happens to me too!  One thing I notice is that the longer I listen, the better it all sounds!  I often wonder... is it because the tubes and everything is warming up and getting into its groove?  Or is it because the adult beverages are loosening up my eardrums.  Ha!

Either way, it works!