KT 150 Amp Options

It is tax return season, which usually means I immediately spend it all on a piece of equipment. I've been looking to upgrade to an amp that has been designed for the KT 150. They have been around for about 2 years now but I don't see a lot of amps designed for them. ARC came out with the REF 75 SE, which seems like a nice amp. However, I run an ARC SP3-C for my pre, which is an SE out. My understanding is the 75 is balanced which does not make them ideally compatible. I've been waiting for CJ to put out a KT 150, but am not sure if that is even on their radar. Any thoughts on a good KT 150 amp or any rumors on when the market will have some more options?
I wouldn't do it this way. You can have 2 amps with the same tubes in them, and still have them sound completely different.
Quicksilver has the option of using the KT150 in both the V4 and Silver 88. Both suberb sounding with this tube.
They are great tubes for sure... Best compromise in my opinion between the clarity, punch and extension of your favorite KT88 or 6550 and the magical mids of an EL 34... All with extra everything and gusto! Roughly what's your price point?
Hi Jgottget

My Jolida JD-502P amp works just fine with the Tung Sol KT-150s. It wasn't designed with the Tung Sol KT150s in mind but it can definitely handle them. Originally it comes with Tung Sol reissue 6550 tubes.

With the Tung Sol KT-150s in my Jolida 502P a long with Old stock Mullard 12AT7s and Gold Lion 12AX7s I experience what Lissnr stated above. I've got the punch and extension and then some of a KT88 and the sweet mids of an EL34.
I'd suspect your Quicksilver suggestion is on the mark.
04-16-15: Tubegroover
Quicksilver has the option of using the KT150 in both the V4 and Silver 88. Both suberb sounding with this tube.
Quicksilver V4 is an excellent suggestion and according to Mike Sanders, SE model has superior SQ to XLR.

Also checkout Carver Crimson 350 and Primaluna Dialogue Premium HP.

I was seriously considering QS V4 but THANKS to a lousy BM dealer, I purchased ARC Ref250 with ZERO regrets.
If you want to go with an ARC amp, you can get adapters for your single ended cables. Check this out:


Nice preamp, by the way. A friend uses the ARC SP3-A and it sounds great.
04-17-15: Oregonpapa
If you want to go with an ARC amp, you can get adapters for your single ended cables. Check this out: www.doublehelixcables
In contrast to most amps having balanced internal signal paths and providing only balanced inputs, many and I suspect most such ARC amps will not work properly with adapters. I believe that what would happen if a single-ended signal is provided to those amps via an adapter is that only one half of the balanced signal path would see the signal. Among other consequences, that would reduce the power capability of the amp to not much more than 25% of its rating, since the maximum output voltage that could be provided would be not much more than half of what it should be (power being proportional to volts squared).

What would work in a reasonable manner is to use a suitably chosen audio transformer between the preamp and power amp, which would convert the single-ended signal to a true balanced signal pair. The Jensen PI-2RX or, at a higher price point, the SMc Audio Flex-Connect, would most likely be suitable choices for use with a stereo (not monoblock) amp. A pair of single-channel Jensen PI-RX transformers, and perhaps also the Flex-Connect, would be suitable for use with monoblocks.

-- Al
Jedinite24, I am surprised to hear that the Jolida 502P amp can handle the KT150 tubes. Recently I was speaking with Jerred, a tech at Jolida, and he told me that Jolida is working on producing an amp that is designed for the KT150 tubes although it will be considerably more expensive than the 502P. He says the KT150 tubes sound way better than the KT90 and KT120 tubes, which to his ears sound "brittle" and not as musical.
I agree with Zd542. Just because an amp uses the same type of tube does not mean a thing! If that was the case then all amps would sound the same! More goes into the design of the amp than the type of tubes used. That being said, I do like the Quicksilver amps I have using KT88's or EL34's.
Charles1dad, what has been your experience with Quicksilver which would lead you to agree with Tubegroover's assessment? Thanks...
The Primaluna HP monoblocks can use KT150s. They sound almost as sweet as the kt88s but with much more punch. I really like the Primaluna's especially for the money.
I do have to change my answer a bit. What I said in my first post doesn't change, but I wasn't aware that you could use KT 150's as alternates in an amp like the V-4's. It would be pretty hard to mess up with a pair of those. And if you don't like the 150's, you can use something else. Going with an amp like that makes a lot more sense.
Zd542 the older QS V4's cannot use KT150's without significant modification but the newer ones are set up to be able to use 6550's through KT150's, I believe.
Hi Plato,

I heard the same thing from Jolida regarding their thoughts on the KT90 and KT120 tubes. I don't remember if I was talking to Jared or not though. It is true the 502P can handle the KT150 tubes. They have been in my Jolida for some time now. Jolida said I may have to increase the bias to around 700 mV rather than the normal 500 mV with the KT150s in place.
(((Zd542 the older QS V4's cannot use KT150's without significant modification but the newer ones are set up to be able to use 6550's through KT150's, I believe.)))
The older V4s can use 150s
The newer V4 units are now manufactured to take full advantage
of the 150s
Quicksilver dealer
I've own a Quicksilver full function preamp for 20 years(now used in a second apartment system). It clearly outperformed my then Audio Research SP9 MK II and later a friend's Reference 2 line stage(5x the cost). It still sounds very good and is utterly reliable over all this time. This company tends to fly under the radar despite their consistently high quality componrnts for very reasonable money.

Word of mouth from people I respect say the QS V4 is an excellent amplifier. I'm inclined to believe the current V4 with improved transformers is quite an amplifier.
Thanks, CharlesÂ… I'm considering the KT150 Silver 88 Monos as I don't really need the extra power of the V4, and the simpler circuit (two output tubes per channel vs. four) would seem to potentially allow for a more "direct" sound. Have you (or anyone else reading this) heard the KT150 Silver 88's, or know what the word on the street is regarding these?? Also, does anyone have any first hand experience with the Jadis i50, another KT150 design?
I haven't heard these two QS amps in any form of direct comparison so I can't offer an opinion in that regard. Based on principle and personal listening I agree with your premise. If power is sufficient I'll choose the amp with the simpler circuit and fewer output devices. Others will say the more power the better(so choose the V4) but I don't believe that's true. Naturally you'll get varying opinions on this topic(simpler vs power).
Weebeesdad, I HAVE heard the Silver 88s with the Kt150 tubes and the V4s. I too am considering auditioning them in home in my system but am not going ahead with this unless/until I'm committed to buy if it is a no brainer choice. The reason being is that I really like what I have BUT there are things in the presentation of the Quicksilver with that tube that have really grabbed my attention, a body and harmonic resolution and texture, that I'm not getting with my amp as MUCH as I like the other aspects, tradeoffs. I am planning a visit to the dealer's within the next week or two and am bringing my speakers to see if they might be what I expect before proceeding with a further in home audition. While I've always liked Quicksilver over the years they have never been on my radar as they are with this tube. Did my taste change or is the amp with THAT tube that is making me consider them? I don't know for sure but all I can say is that both the V4 and 88s are impressive.
Thanks for your reply, Tubegroover. Please do give us your impressions after your upcoming audition with your speakers (even though I know you don't normally do impressionsÂ…).
Tube Research Lab
What are your current speakers?
Ayon has some KT150-based amps.
I am using the DeCapo's at present. I have heard these speakers at the Dealer's with the lowered powered QS monos but not the Silver 88s. He has a pair of Dulcets which I heard recently but paired with another amp and at that time I asked if he had ever tried the Silver 88s with the Dulcets or the Decapos and he said never, seemed to me that it might be a good pairing based on what I heard with other speakers. He called me a few days later and said the pairing with the Dulcets sounded fantastic and that I had to hear. So probably this week or next I'm going over for a listen. Since he doesn't have any Decapos in stock I'm bringing over my pair.
This should be a very good pairing with the Siilver 88 KT150.
I'm thinking so Charles and I also agree with Weesbeedad that simpler is generally better. The V4s are amazing, if you need the power but they also put out considerable heat which living in Florida is always a consideration to me and quite frankly I can't see where I would ever own a speaker going forward that would require that type of power. In addition the 88's have a lower output impedance making them ideally suited for different speakers.
I think the new Jolida KT150 based amps are the fancy new two piece mono amps. Ditto on the Jolida 502p...I went in casually with no regard for terrifying heater supply disasters with KT120s and they lasted almost 3 years under hard use, sounding great (rig dependent maybe...but friggin' great). The KT150s I replaced them with have been tootling (audio term...meaning "to tootle") along perfectly for nearly 4 months and sound fabulous...I bias 'em at 500 as that's easier, and I'm not smart enough to know why 700 is better...in any case, note that relative to what the competition charges for tube amps, you could buy two 502ps and run 'em in mono if you thought you needed more heat in your listening area...but note that the factory modded 502s remain a nearly unchallenged bargain as a quiet running powerhouse of glass based electron manipulation.
As you know, Rebbi reports fabulous results using the same speakers as you have. He uses an 8 watt SET, and enjoys all genre of music with this set up. It would seem that the silver 88 amplifier with 80 W of power would be more than sufficient for your needs.
Well Charles I'm more than certain that 90 watts, the case with the Kt150 tube in the Silver 88, is going to be more than sufficient. I'm going to find out tomorrow how the QS and DeCapos pair up.
I'm glad to see the interest here in the Quicksilver brand, especially the silver 88's. I'm considering purchasing a pair for my second system. I would more than likely use the KT150 tube option. Any comments about the amps would be appreciated.
Hi Rudge

I did have the opportunity to audition the QS Silver 88 with the KT150 tube with my DeCapo speakers. Front end included a Copeland CD player and a Clearaudio Ovation TT the QS entry linestage. Not sure about cabling or the tube phono stage used. There was a significant difference between the CD playback and vinyl so far as performance but overall I was certainly impressed enough to audition at home which will be in the next month or so. Overall sound is smooth, rich a bit rounded on the leading edge, notably on the CD playback but not at all evident on the vinyl playback. This was my ONLY reservation going forward since I am so used to an incisive leading edge presentation, that balance between too soft and too incisive or crisp. I'm sure some of this impression could have been related to the ancilliary components. Other than that I would say that the overall resolution, dynamics, timbre, depth and the inner harmonic detail and transparency were just top tier and completely engaging. A "forget how it sounds get into the music" particularly with vinyl playback. These amps remind me of good SET playback in their presentation of the beautiful harmonics and tone present in music that is often bleached out by many amplifiers. There is nothing analytical here, just beautiful music. I expect in my system and room, less that wonderful Clearaudio tt set-up, the CD playback will be better than what I heard at the dealer's. I'll be auditioning at home in a month or so when I finish setting up my room.
Well you certainly had a very positive audition with the Quicksilver amplifier. Given your results and Rebbi's terrific impressions using the same speakers is interesting(very different amplifiers). For pure curiosity I'd love to hear the Quicksilver and the Audio Note Kit 300b SET in direct comparison with the De Capos. Seems you couldn't go wrong with either based on what both of you have written.
"For pure curiosity I'd love to hear the Quicksilver and the Audio Note Kit 300b SET in direct comparison with the De Capos."

Me too Charles! It's so interesting you brought that up since I was so immersed in that thread and the final outcome and ALSO because I recently had a really enjoyable experience with an 300B SET set-up, not all perfect but just so throughly engaging. I still have this underlying suspicion that 8 watts would not work for me long term with the DeCapo speakers and my overall tastes in music, I just don't believe based on past SET experiences that the speakers are efficient enough for all music and time would bear that out. The Quicksilvers weren't perfect either during the audition but I have a strong suspicion that what I heard was less related to the amps than the overall set-up. This is the question, is that "softness" an intrinsic character of the amp or not and will it play out over long term listening and become a distraction? Initial impressions can often be misleading but what was most telling to me overall was that I was REALLY trying to analyze, as I do during any audition, but couldn't help but be drawn into the music and performance, always a good sign. I brought a large variety of different music that both sounded great and also had recording issues to see how things fared overall. Bad recordings and great recordings but all music that I really enjoy. The Silver 88/DeCapo combo was quite engaging overall.
It's certainly within reason that the QS may suit your needs better. Rebbi's experience is very adamant based on extended listening. Brownsfan also reports very similar impressions with the De Capos. He used two 8 watt amplifiers, Coincident Frankenstein and their Dynamo SEP. His findings are very positive as well. This reflects the obvious subjective nature of it all.
Well Charles I may be wrong with my suspicions. Sure would like to listen first hand, it's the only way to know for absolute sure.
You don't need an optimal match of components to sound really good. But chances are a more optimal mating can sound even better. It a may all be good but there is always good, better and best.

Nothing wrong with settling for "good" but inquisitive miinds always want to know what might be better. It's both a blessing and a curse depending on one's perspective.
I agree concerning one's perspective. It can make one very happy and willing to explore/appreciate alternative paths. It can also result in chronic frustration and bewilderment as well.
TG, thank you for incisive review. The sound you described for the amps is compatable with what I am looking for. I will be taking a very serious look at purchasing the amps direct. There are no dealers anywhere near where I live. Again, thank you. Your comments were most helpful.
Good luck Rudge, I feel quite confident you'll like them. At least there shouldn't be any negative surprises as they work with a wide variety of speaker loads. I'm fortunate that I have a dealer that allows me to take things home to listen before committing. Please post again when you get the amps to let us know your impressions. I've also been quite impressed with Mike Sanders who is always there to answer questions. Seems like a really solid company.
Anybody has comments on the Rogers Fidelity EHF-200 MK2, which uses four pieces of KT150?
Is it a tube newbie friendly amp?
Appreciate your comments. Thanks
Rogers amps are beautiful, great sounding, and expensive.
Tubegroover, I just wanted to let you know i ordered the Silver 88's from Mike Sanders today. I'll let you know how I like them after I get them in and set up, and played for awhile. Mike was great to deal with..
Please do Rudge along with your system. I'm planning on borrowing a pair from the dealer for an in home at the end of the month.
I just picked up the Silver 88s a few days ago for evaluation. My concerns were quickly laid to rest concerning a leading edge softening that I heard at the dealers. It seems the QS linestage was a major contributing factor to that impression after listening to that both the remote and regular linestage in a friend's system, an overall softening which has typically been my impression of QS over the years, musical but a bit lush.

Well the amp is a different animal with the KT150 tubes. The magic that I heard originally with the V4s carries over to the Silver 88s. This is one fine amplifier with texture and body AND superb resolution of the subtle harmonic details that gives greater insight into a musical performance. So I would say for the money it should definitely be considered by anyone willing to spring the price and wants to hear what all the fuss is concerning the KT150 tube. There is nothing wanting, as a matter of fact I spent all last evening listening, even missing the NBA conference finals going from one disc to the next.
Concur with positive comments above re the KT-150 tube. I just upgraded my ARC Ref 150 amp to SE status. The SE upgrade includes KT-150 tubes. Bottom line: my amp sounds noticeably better.

See the ARC Ref 75 SE and Ref 150 SE threads that are still active for more comments.
Tutbegroover - Please keep us updated on your listening impressions as you further evaluate the KT150 Silver 88s. Thanks!!
Tubegroover - If you like those Silver 88's you should keep them, they may be the last available. I put an order in for a pair of 88's on April 19th and was informed on the 23rd that they were discontinued and the order would not be filled. Mike offered me a deal on the V4's but they are too much amp for my speakers, stand and room. After some calling around I found out that there was some supply issue with parts or something. Quicksilver will begin production this week of a new Mono 120 amp which will have a look similar to the Mid Mono's. They are 120 watts each with KT 150s, 12AU7 and a 12AT7 and will sell for $3,995 a pair. I should have a pair in 10 days, my guess is serial number 001 & 002 (I mean who else would buy a product that doesn't even exist yet?).
*the order was placed on May 16th, apparently I don't know what month it is.
Jgottget, you must of just missed out, it seems Rudge ordered a pair a week before you. I did speak with Mike Sanders concerning the differences other than the input/driver tubes used. Bigger transformers and more power but a higher output impedance. One of the appeals to me about the 88s is that they can be used with a wider variety of speakers. So far as sound goes, my impressions are pretty much the same. What has me scratching my head is why some amplifiers that aren't NEARLY as musically engaging as these cost so much more. One thing about some of the older tube designs with a rich presentation was what I call the halo effect which was always a distraction. These are really modern sounding, rich, natural, neutral in character overall in that you hear what is on the recording. Another thing I have observed about some amps with wide bandwidth, my current amp included, is that there is often a peakiness at points in the upper frequencies that can cause distraction. This is heard with certain instruments including recorder, flute, piano and soprano voice. I have been going through some of my "problematic" recordings to see how the 88s handle these passages. They remind me much of the Joule Electra OTLs that I had in the system years back in that they maintain musical integrity of the instrument/voice without the peakiness with air, like you hear in live acoustic performances.

I certainly haven't listened to everything out there but I've heard enough to consider these amps exceptional in presenting music in a natural, detailed manner without any obvious irritants or amusical artifacts. Vocals and instruments are generally presented more realistic and engaging. I'm sure there must be better but going back a few months ago to a well over 100K plus system I listened to at a dealers. The thing that struck us all was trying to determine what was wrong with what we were hearing in a well designed acoustically treated room, good sound in some respects but distracting at the same time, hmmmm. It reinforces to me, I suppose, that the recipe is far more important than any of the individual parts. Maybe a pair of V4s would have changed the equation, who knows?