Alekz said Yarrggghh... These binding posts is a catastrophe.... One of them has the nut stuck, and two are loosely moving with no possibility to tighten the cables. I had to put thick a rubber pad between the contacts to prevent accidental short-circuiting (the posts are placed way too close to each other).Alekz, please contact either Scott or myself via email to resolve.I think I will have to open the cover and re-tighten them from the inside. Not something I would like or expect to do…
A little late to the party, but let me jump in with my first post.
I just wanted to say that I thought the packaging was superb. The only potential improvement would be to cut a finger slot, mid-amp, in the foam. I ended up tipping mine on its side to get a hand-hold. I liked the reusable box fasteners.
I just upgraded my home speakers from the Infinity RS4.5s to the Infinity Betas. I had the Infinity Betas about a week before the new BHK amp arrived. So, I had a chance to listen to my old amp with the new speakers. With Paul’s guidance (since he owns a pair of Infinity Betas), I was trying to place the speakers for the proper sound stage and imaging. Despite some improvement in stage, the sound continued to be muffled. Things sounded like they were recorded with a wet rag over the microphone. The piano and violin recordings that I was listening to sounded flat and lifeless. I knew the speakers were capable of much more.
The new amp arrived. With the help of the wife, we moved the new amp into its place of prominence. I hooked up the new amp and right out of the box, it was an OMG moment. Everything came alive. The clarity of the instruments was amazing by comparison to my reference amp. It was if I was having a live performance in my living room. Sorry it took some of you longer (break-in time) before you could have such a moment.
As further testament, my wife, who has had very little interest in sitting and listening to music, joined me for the initial test run. She had listened to a couple of songs on the old amp (not impressed, it didn’t hold her attention). But, when we played the new amp she was amazed. The word she spoke was “Wow!!!” (This is like seeing the Grand Canyon for the first time kind of Wow). We listened to ThePianoGuys - “The Mission / How Great Thou Art” - off their Wonders album and it literally brought tears to her eyes. Now if that isn’t the kind of response you want your audience to have, I don’t know what is.
We have continued to listen to a wide variety musical genre over the last couple of weeks including the sample disc. I’ve tried to summarize below.
Just a Little Lovin’
This is just a fun track. I like the musical intro. The Beta Speakers have lots of presence on the low notes (I’ll have to try switching the BHK with my HK775 Mono amps (used for the base towers) to see what improvements it provides to the base-end). Shelby Lynn’s voice is spectacular. I know you asked to compare the qualities of my reference amp (Superphon DM 220) but, I just can’t do it.
Requiem: Agnus Dei
This is an amazing track. I had the pleasure of listening to this song with the BHK Beta amp at Listening Room 1 with Paul mid-Feb. The Infinity IRSVs are just incredible on this track. When the pipe organ plays the low note, it’s very embracing. The vocals as well as the other instruments presented themselves as if we were mid-stage with the Choir.
Within
The three components that you listed in your write-up were all discernible. The cymbals were positioned and sounded as you described. The piano is becoming an instrument that I can enjoy listening to again. With my old amp, the notes ran together in a smear; whereas, the BHK brings them alive and presents them with such clarity.
Alfie
Paul described the ‘punch in’ after he was auditioning the BHK Mono amps. I wasn’t certain that nuance would show itself with the stereo version. But, alas it did.
Giant Japanese Drum
This track is unique. I warned folks that are listening to this for the first time that it’s a bit weird. But, when the big drums explosive thwack hits and startles them they begin to appreciate the presentation.
I appreciate Paul sending this sampler to us to help level set the audition. But after reading others reviews as well as from my own experience, it’s music that we’re already familiar with that brings the most satisfaction.
When I went to PS Audio and had a chance to listen to Music Room 1, I had taken along a CD of Celtic Women, The Greatest Journey that I had listened to a few times. Mairead Nesbitt, the violinist, played “Shenandoah the Contradiction”. In addition to being beautifully played, I notice a unique sound quality to her (if my research is correct) 300 year old 9/8 Matthias Alban violin. The instrument resonated with such clarity that made me feel as if I could tell you what wood was used during its construction.
Paul then played a song from Classic violinist, Itzhak Perlman. He’s an incredible performer, with a different style. But what I noticed the most, was the different (unique) sound that his violin made by comparison to Nesbitt’s violin. I don’t know whether it was his Stradivarius or his Guarneri or something another of his earlier violins.
I have since had a chance to listen to Anne Akiko Meyers play Clair de Lune from her Seasons album on her Stradivarius. That’s a phenomenal combination. Not only does she have the ability to impart such emotion into the strings, but also the instrument seems to disappear. It’s difficult to describe, but something I’m confident you’ll enjoy. This is rapidly becoming one of my favorite songs/artists. The wife got goose bumps listening to this song.
One thing that I’ve noticed as I’ve auditioned the new amp and speakers to friends and family is that they all light up with smiles on their faces.
Great post, Eric
And welcome to the forum!
Thanks Eric!
Alekz saidAlekz said Did anybody else notice any changes in the sound between 200 and 400 hours?What? Still nobody?
I’m only at ~ 120 hours, so I’m not there yet. Does it really improve significantly? I thought it was pretty darn good already!
–SSW
Elk said Great post, EricAnd welcome to the forum!
+1 on both counts. Nicely done. I agree that the music we are already familiar with is the most telling. And the story it tells is the BHK 250 is simply amazing.
Alekz, I haven’t noticed any radical sudden (or not so sudden) changes in the sound. But then I don’t trust my aural memory to reliably go back hundreds of hours.
We did not have time for music for quite some time, but the amp was under constant XLO burn-in load, so when we had our next listening session, the amp “jumped” from ~240 (see my first review) to 400+ hours. In other words, the amp was constantly up&running for 18 days.
I my first review I mentioned “treble smearing” and brightness. I played the same tracks and did not notice these issues. The “ear bleeding” sibilant track was surprisingly listenable, musical and even enjoyable. Yes, the sound engineers “missed a bit”, but I could “see” the face expressions of the singer, so I think the amp passed this test.
I switched from Simon & Garfunkel to Pentatonix, then to Shelby Lynne (DSD). And this is when I noticed something strange. We usually listen at “40-44” (DS level). DSD tracks are recorded at around -6dB, but increasing the volume did not help much. The sound was lifeless, not focused, boring, and … dry.
I do not like dry sound, it makes my throat soar. I prefer liquid, almost “wet” sound (that’s why my preference was Meridian, and not Linn).
Switched to Suzanne Vega. Yes, familiar sound, with more tamed highs, than a week ago, but definitely dryer. Imogen Heap’s “Hide and Seek” lacked emotions.
Our favourite Mozart’s Requiem recording (sir Solti, 1991, Vienna) sounded terrible. Messy, not involving, with no body even at “55”. Quick switched to Hogwood’s version - sounds much better, and that unreal Kirkby’s voice… But still, no body… It looked like the BHK250 ran out of magical juice. That was the first time I was thinking about replacing the BHK250 with my old good Pass Labs x250.
However, I noticed that the amp was very hot. I turned everything off (and a thunderstorm was coming anyway) and decided to try again next day.
On the next day, we set the volume to “60” (never before!). And the Requiem slowly “came to life”, yet it did not reach the power of the x250. Rachmaninoff’s Concerto N3 Part 3 was very convincing. We did not listen much on that day and decided that the BHK250 is very picky and does not like some classic music.
Next day was dedicated to “cleaning everything”. Curtains, floor, the audio rack, carpets were vacuumed, washed or steam cleaned, the audio equipment was disconnected, repositioned and also cleaned. At the end of the day to test that everything is still functioning, I played Sting’s “If on a Winter’s Night” album. The first track made us squirm - the clarinet almost exploded our room with a deafening resonance around 300Hz! But the cause was found very quickly - during the cleaning we moved a couple of small carpets, what left the stone floor “naked”. The solution was placing a sitting sack (exclusively used by our cat) on the spot between and in front of the speakers. The resonance immediately disappeared and we enjoyed the rest of the disk. But Sting’s voice was on the husky side.
Today I was throwing at the BHK very various music. Zaz (highly recommended! http://en.wikipedia.org/wiki/Zaz_(singer) ), Paolo Nuttini, Tracy Chapman, Katie Melua - everything sounded fantastic! Extremely involving, clean, clear, balanced, transparent, like a new system. The volume was around “42-45”.
And, finally, Requiem. Ton Koopman’s version sounded strange. “Rex” had no power until the volume was set to “64” and the recording room acoustics exaggerated “ss” and “ts” in “Recordare”. Switch to sir Solti. “Rex”… mmmm… not bad. Increased the volume to “70” - YEEESSSS!!! THIS IS IT!!! This is Rex Tremendae!!! Ohhh my … GOOSEBUMPS!!!
Conclusions #2.
o- I have no idea why the sound was so thin and lifeless after a long run. Overheating?
o- BHK250 needs AT LEAST 400 hours of break-in. Possibly more, I do not know yet.
o- BHK250 is very sensitive to recording levels. Our current DS volume diapason is 35-70, (never more than 50 with x250). It might be related to more control and less resonances.
o- The room acoustics is very important (didn’t we know that before?)
o- You might need to reposition and readjust the furniture, speakers, etc.
o- If your system sounds strange, try next day (who knows, it could be the power, EMI, the weather?).
o- Cleaning always helps. Your room looks better, and wet cleaning removes accumulated static electricity.
o- BHK250 is a very good amp 
o- BHK250 binding posts suck 
o- I want the monoblocks 
I’m wondering if it was your break in method (not using speakers and using resistors instead). Initially my BHK was very volume dependent- it had to be cranked up a bit to get great sound. After a lot of break in this is no longer so.
It may be that the tubes don’t like being left on constantly for such a long period.
woot said I'm wondering if it was your break in method (not using speakers and using resistors instead). Initially my BHK was very volume dependent- it had to be cranked up a bit to get great sound. After a lot of break in this is no longer so.The last 10 days I was using powered off speakers as the load. I have Martin Logan Summits with active subwoofers, so when the panels are discharged and the built-in amps are off, they remain silent. I can play the XLO burn-in track at "40" on the DS, and the emitted sound is barely noticeable.
BTW, what was “a lot” in your case?
stevem2 said It may be that the tubes don't like being left on constantly for such a long period.Yes, my thought as well.
stevem2 said It may be that the tubes don't like being left on constantly for such a long period.Tubes are far from fragile and are happier left on, then turned on and off and heat cycling. The amp uses tough little 6922 input tubes, originally designed for tuners which were left on for hours. They are typically rated as possessing a 10,000 hour life.
Think turning on an incandescent light bulb and leaving it on over night. No biggie.
I agree in general but this was 18 days straight and playing constantly. It’s not surprising the amp got hot.
Of course, it reached thermal equilibrium just as it would after a couple of hours. Electronics and tubes get warm. Nothing to worry about.
If you are convinced it is getting too warm and is in a well ventilated spot, take some measurements and let PS Audio know. I would be surprised if the heat dissipation is inadequate, but it is always good to make sure.
Is there some clever way to keep track of the time on the tubes? I’m use to having a “hour meter” on the airplane or the lawnmower. Is there a simple timer that I can turn on when I power up the amp?
Not really, but the way these tubes are used it shouldn’t be a concern. There’s no reason to replace them more often than once a year, and perhaps every other. Unlike power amp output tubes, which go pretty quickly, these are in for the long haul and should easily give you a year or two.
Eric Fischer said Is there some clever way to keep track of the time on the tubes? I'm use to having a "hour meter" on the airplane or the lawnmower. Is there a simple timer that I can turn on when I power up the amp?I bought one of these https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=2095074 and use the 12VDC trigger to run it. It counts hours as long as the 12V trigger is on, which, by the way, is when the BHK is on.
–SSW
I did not have time to listen, but I kept the amp cooking 24x7 and today it must have ~600+ hours. I did not notice any significant changes since 400 hours (unlike 200 -> 400). Probably, just a bit more transparency and air.
So, I would say, that the break-in time is around 400 hours.
… and Yale OS made BHK250 sound even more fantastic … Now I can’t stop listening.
Oh, as I mentioned in the Yale thread, the dryness is completely gone. So it was not a property of BHK250, but a “bug” in Pikes Peak OS.