[AllanS]

I’m working a short list of pre and power amps and have a question about matching components types/classes with use profile.  I work from home in what is being transformed into a semi proper listening room.  So my system is running at least 10 hrs / day 5 days a week.  Most of it is background music, nothing critical listening but pleasant at low SPL.
For those times when listening is critical I’m enamored of Class A amps and tube preamps but am wondering if those are really poor choices for my profile.  I’m imagining two space heaters going all day long and expensive tubes doing little more than providing ambient lighting.  Component life and efficiency are important for much of the day but I want the good stuff on tap when called for.
Are Class A and tubes poor choices?
Thank you.

[Freo-1]

Would recommend a used Devialet Expert or Expert Pro.  The amp is class A voltage, class D current,  built in DAC and phono.   Designed for exactly the type of usage you outlined. 

[mresseguie]

Allan,

Welcome to AC.

Do you already own a Separate/dedicated DAC that you're not necessarily seeking to replace? I read through your previous posts for a bit of background, and noted you're pretty keen on the Schiit Freya S, yes?

With the likelihood that you're considering separate components, I have a long-winded suggestion <thanks to my waking up at 5 am this morning>. Well, okay, I probably have more than one. I'll supply you a bit of background so you'll know where I'm coming from.

For the past 4 years or so, I have been a full on tube junkie. My main system consists of a tube DAC, a 6SN7 tube pre, and a KT88 tube amp. I love the music that comes out of my speakers. I listen anywhere from 3 to 8+ hours each day. Much of this is low level music because my wife would likely divorce me if I turned it up as often as I wished. I'm well aware that running tubes this much will cause them to eventually fail, and good quality tubes are getting expensive. With this in mind, I've been searching for a SS amp that meets my needs and wants. For a while, I had thought I'd found it in an IceEdge 1200as2 amp. However, after my not using that amp for 2 years now, I came to the conclusion it was not 'the as good as my KT88' SS amp which I have been seeking.

[Edit: I have no intention of replacing my 6SN7 preamp in this system.]

What follows is a subjective explanation of my research and decisions: With great interest, I've been reading up on the newest Class D amps, GanFet amps, and Purifi amps in the hope that one of these designs would satisfy me. Based soley on reading reviews and personal testaments on various forums, I'd eliminated the Purifi amps as being more analytical than I wanted (not interested in debating pros and cons with any Purifi lovers who read this). Then, a couple months ago, a friend in Taiwan purchased a GanFet amp. He wasn't satisfied with its SQ, so he modded it quite extensively until he was happy with the SQ. [He's very particular about what amps ought to sound like.] I haven't heard it yet, so I don't know how it sounded before nor after, but I'm sure he'll insist I listen to it the next time I'm there. His complaints kind of steered me away from GanFet amps - at least until the technology has matured a bit more.

In mid-January, I decided I had to try out a new dual-mono Class D amp that had just been released. It's billed as being warm like very expensive Class A amps, yet very revealing and low distortion. This amp is the Nuprime Evolution STA amp. It's been in my system for about 5 weeks now, and it's gotten close to 300 hours of burn in. It took 200 hours till I stopped noticing significant changes. I'm delighted with its SQ. It is warm sounding and it is very revealing. It's a tad warmer than my KT88 amp yet I hear instrument sounds now that I hadn't heard as distinctly before.

Prior to buying the Evolution STA and deciding to keep it, I had intended to audition another recentlly introduced offering which has been getting rave reviews - the Audio by Van Alstine DVA M225 mono amps. I'd like to someday listen to these mono amps in my system, but I'm in no hurry now.

Regards,

Michael

[Tyson]

I'd focus on getting speakers that are high efficiency and an easy load.  That will make your amp requirements much lower/easier. 

[Freo-1]

I'd focus on getting speakers that are high efficiency and an easy load.  That will make your amp requirements much lower/easier.

Good thought. The issue with high efficiency speakers is finding one that has a uniform flat frequency response.  Not easy to find.

[Tyson]

Good thought. The issue with high efficiency speakers is finding one that has a uniform flat frequency response.  Not easy to find.

If it was me, I'd probably find a nice HE speaker that I liked and then send it off to Danny at GR Research to rework the crossover to get a flat response, plus higher quality crossover parts. 

[AllanS]

Thanks much for your responses and help.
I am amazed at the many different form factors for equipment that in one way or another all do basically the same thing.  I’ve never seen or heard of anything like the Devialent Expert or Evolution STA, which I would not have expected from Nuprime.  High performing amps are supposed be mammoth  heavy, not something you toss around like a tablet. 
 I haven’t figured out much but I am taking the advice of getting some nice, efficient speakers in place first.  I’m leaning heavy towards the Spatial M4, getting them properly set up and broken in with the Ragnarok 2 that’s been keeping me company for the past couple of years.  Once I’ve decided they’re keepers I’ll start the amp parade.  Actually I’m hoping to whittle the short list down to 2 or 3, which is where all the questions are coming from.

 

Allan,
Welcome to AC. 
Do you already own a Separate/dedicated DAC that you're not necessarily seeking to replace? I read through your previous posts for a bit of background, and noted you're pretty keen on the Schiit Freya S, yes?
Prior to buying the Evolution STA and deciding to keep it, I had intended to audition another recentlly introduced offering which has been getting rave reviews - the Audio by Van Alstine DVA M225 mono amps. 

Thanks much for the welcome Michael and for devoting some of your sleeplessness to this. 
I am looking for separates for little other reason than I’ve always wanted to and because I’d like to maintain the flexibility to change things up. 
I do have a separate DAC, a Schiit Bifrost, that I don’t intend to replace anytime soon along with a Vault2i.  I also have an old Pioneer PL707 that is giving me fits right now, but that’s a problem for another day. 
 As my first serious move into this world I don't want to go all in on tubes but do like the idea of a tube preamp for all the reasons others say they like them.  I’m leaning Freya+ for many reasons, not the least of which is the ability to bypass and preserve the tubes. 
The amplifier is where I’ll get stuck going in circles.  Several have gotten my attention for various reasons. Of course I've not heard any of them but the Pass Labs XA25 seems to be the most promising, except that whole space heater thing.  Others that have caught my interest are the PS Audio M700, Benchmark AHB2, Bel Canto REF600M, and as of today the same Van Alstine DVA M225.  So yeah, the possibilities seem to run the SS gamut.

[BruceSB]

If you love class A power amps then go for them!!
My Sugden Sapphire power amp sounds way better than the Quad 606 that I had previously.
AND ...
Not all Class Amps run particularly hot.
I know that some are reputed to be able to fry an egg.
But not my Sugden Sapphire!
It runs only marginally warmer that my Quad 606.
It is merely warm, never uncomfortably hot - you can hold your hand on it forever and not be too hot!
And it sounds glorious.
Like all class A amps are famous for.
But here is the thing you need a user to tell you how hot it gets!
Hope that helps.
Bruce

[BruceSB]

I had a little think, and I would like to add a couple of things to my above post.
First off I have added a picture of my Sugden Sapphire.
Next I would make a comment about speaker sensitivity.
My speakers are 91 db and my amp copes very easily with them.
Thirdly, you mention Spacial speakers, I think that they would be wonderful partners to a class A amp.
Not simply because of their very high sensitivity but also because of the lack of a box!!!!!!
Most people are listening to the music plus the box - and they do not even realise that they are listening to the box!
Spacial are on this forum, look them up if you have not already done so.
If I did not love electrostats so much I would very seriously consider the Spacials.
All the best with your upgrade.
Please keep us informed.
Bruce

[Early B.]

You're encountering a dilemma because you're attempting to combine your reference system with a background system and based on your preferences, they're incompatible due to heat and tube replacement costs. Instead, build two "systems" that share the same speakers. Keep your Schiit components for background music and build your reference system with a Class A amp and tube preamp.

 

[AllanS]

…you need a user to tell you how hot it gets!
Hope that helps.
Bruce

Duh.  Oh course.  Thanks.  I have spent a fair amount of time in the Spatial circle.  That’s where I learned of the XA25 and Van Alstine.

Keep your Schiit components for background music and build your reference system with a Class A amp and tube preamp.

I like it.  Thank you. The Bifrost has both SE and XLR outputs.  After that I just have to figure out how to swap the speakers. 
I don’t know why I didn’t think of this.  A long time ago I was in a similar quandary over a motorcycle.  I had a then modern day UJM (universal Japanese motorcycle) which I loved but wanted a cruiser in the worst (obsessive) way.  I got a small cruiser but was immediately bummed about selling the UJM.  My wife of all people told me to keep both - only because she didn’t want to listen to my whining and crying 6 months later.

[Freo-1]

Thanks much for your responses and help.
I am amazed at the many different form factors for equipment that in one way or another all do basically the same thing.  I’ve never seen or heard of anything like the Devialent Expert or Evolution STA, which I would not have expected from Nuprime.  High performing amps are supposed be mammoth  heavy, not something you toss around like a tablet.
 I haven’t figured out much but I am taking the advice of getting some nice, efficient speakers in place first.  I’m leaning heavy towards the Spatial M4, getting them properly set up and broken in with the Ragnarok 2 that’s been keeping me company for the past couple of years.  Once I’ve decided they’re keepers I’ll start the amp parade.  Actually I’m hoping to whittle the short list down to 2 or 3, which is where all the questions are coming from.

 
Thanks much for the welcome Michael and for devoting some of your sleeplessness to this.
I am looking for separates for little other reason than I’ve always wanted to and because I’d like to maintain the flexibility to change things up. 
I do have a separate DAC, a Schiit Bifrost, that I don’t intend to replace anytime soon along with a Vault2i.  I also have an old Pioneer PL707 that is giving me fits right now, but that’s a problem for another day.
 As my first serious move into this world I don't want to go all in on tubes but do like the idea of a tube preamp for all the reasons others say they like them.  I’m leaning Freya+ for many reasons, not the least of which is the ability to bypass and preserve the tubes.
The amplifier is where I’ll get stuck going in circles.  Several have gotten my attention for various reasons. Of course I've not heard any of them but the Pass Labs XA25 seems to be the most promising, except that whole space heater thing.  Others that have caught my interest are the PS Audio M700, Benchmark AHB2, Bel Canto REF600M, and as of today the same Van Alstine DVA M225.  So yeah, the possibilities seem to run the SS gamut.

If Devialet is on the list for consideration, regarding speakers, consider a pair of speakers that are supported by Devialet Speaker Active Matching  (SAM).  There are now over 1K on the list.