BHK Beta Tester Reports

Paul had wanted to know if, as beta testers, we had had any prior experience with tubes. My limited experience has been my Musical Fidelity Tri Vista SACD player (now a paperweight), and the Aesthetix Calypso pre amp.

Although most of my audio buddies rigs are chock full of tubes!

woot said It has always sounded really good, but yesterday it got meat on its bones in a very noticeable way.
So the change was sudden, like a light switch?

No. But I noticed the changes last night, as did my wife. I have it on all the time when I’m at home, but I do not always critically listen.

Elk said So the change was sudden, like a light switch?
I'm not sure if this is what happened to woot (and I hear of a lot of similar experiences from others with break-in), but I experience this with break-in too. But in my case I know that my variance in perceived sound quality day to day is bigger than the kind of changes we are talking about and I just assume that when a break-in process gets to a certain point the next time I'm in a good listening mood things seem drastically changed... Adding a random number to a ramp can give big steps now and then.

Cool.

Thanks, gentlemen.

Ooops… The long post with photos is gone to /dev/null … Yarrrgghhh… OK, let’s start again…

Update: Weird… I recovered the post thanks to the “Lazarus” Firefox extension, but I can’t save it. The forum says “Saving” and then … nothing … With no errors… And no post …

I have noticed that the BHK is having better tonal balance over a much wider volume span. At first you had to be in a perfect volume sweet spot where the bass/mids/highs all came together. Now that is not the case, and the amp sounds musical and balanced even at lower volumes, which is important to me. There still is that “perfect” volume level for each track, as with any great stereo, but the amp performs well at any volume (I am not talking about paint peeling volume- I do not listen that way). Kudos! This is new and only happened with break in, not initially.

Alekz said Now to the next 200 hours. I wonder if the same 400-hour rule applies here.
I'm thinking yes.

OK, I can’t post photos in this thread… Tried several times in different ways. Giving up … I’d better publish it somewhere else and post a link here…

Unless they are somewhere in the moderation queue.

@Alekz - The forum has a couple of gremlins right now, and posting pictures seems to be one of the issues. See Link–> http://www.psaudio.com/forum/new-forum-issues

Things should be better after Paul gets back from Germany. beer_gif

Aaaaaaaand finally it’s arrived! You know, if you want to speed the delivery up, there is a good always working recipe - get into the shower. Usually they come when you are totally covered with shampoo

Anyway, the box was lighter than I thought, and it arrived without any sticky tape. I wonder it it was opened at the customs or was never “sealed”

bhk250-box-IMG_2904-2.jpg

The “beta-disk” is included:

bhk250-box-IMG_2905-3.jpg

So is the amp itself

bhk250-box-IMG_2906-2.jpg

The most difficult part was to get it out of the plastic bag:

bhk250-IMG_2908-2.jpg

After reading the previous comments, we place the amp on an old IKEA carpet (heavily used by our cat to sharpen his claws) to easy to slide the amp around or turn it to the side:

bhk250-IMG_2909.jpg

My XLR cables are not long enough to get to the amp not placed in the rack, so I bought a pair of cheap microphone 3m cables:

cables-IMG_2911-2.jpg

and connected the amp to the DS and the PPP:

system-IMG_2913-2.jpg

I decided to follow Bascom’s advice and bought two 27Ohm 17W resistors (50cents each):

resistors-IMG_2910-2.jpg

And connected them to the output terminals:

resistors-IMG_2915-3.jpg

We usually listen at the volume set to “43” on the DS. Just in case I set it to “30”, started the XLO burn-in track, but the resistors did not become warmer. “40” - no changes. “50” - after the sun went down the resistors were stone-cold. OK, “70”. Aha! Finally warm to touch, the right one is clearly warmer than the left. I think the reason is that the right channel of the XLO track is recorded with +3db compared to the left channel, so I adjusted the balance and this is how I’m going to keep it for the weekend.

My current system:

DirectStream -> PassLabs x250 -> Martin Logan Summit

The DS and x250 are connected to PPP. All cables are MIT Oracle (power) and MIT Oracle 3.x

The output terminals are inconveniently placed too close to each other and aligned horizontally (instead of vertically) , so the thick non-flexible loudspeaker cables have to go up first instead of directly to the side (like on PassLabs amps). That will effectively shorten the cables and add tension.

Alekz said The output terminals are inconveniently placed too close to each other and aligned horizontally (instead of vertically) , so the thick non-flexible loudspeaker cables have to go up first instead of directly to the side (like on PassLabs amps). That will effectively shorten the cables and add tension.
Interesting observation. I had to look at the back of my current amp to check on its output terminal location. Once the speaker cables are plugged in, I don't think this is one of those things any of us worry about. My amp now (Musical Fidelity NuVista 300) has its sets of terminals vertical. I checked the back of my speakers (two sets since it can by biwired) and those are horizontal. I guess there is no standard way of placing these.

I run two sets of the Morrow Audio Elite speaker cables to the speakers. Since the positive and negative runs are each individual cables, I have 4 separate cables going to each speaker. Naturally, I had to check to make sure I had all the cables plugged in correctly.

The picture of the back of the BHK Signature 300 also shows the two sets of output terminals horizontal but further apart so perhaps this will be less of an issue. For me, my speaker cables are terminated with Furutech Banana’s. I should not have a problem.

Speaker terminals is a different story, because speakers are placed further from the real wall, so there is more space. Also, speaker terminals are usually located higher (think of speakers on stands), so the cables go downwards, hence the speaker terminals should be placed horizontally. The amps are placed closed to the back wall and closer to the floor (since they are usually heavy), the cables go sidewards to the speakers, hence the best alignment for the terminals is vertical.

I know of two exceptions: Magnepans and Quads, where the terminals are placed very low, but I do not remember how they are aligned.

Interesting thought. I have seen both orientations on the back of amps. The two amps I currently swap back and forth in my main system have horizontal placement.

I can understand having a preference based upon where one is placing an amp, cables used, and speaker location, but I have never had a problem either way. Cable dressing of large speaker cables is always a bother.

Magnepan 20.7 and 3.7 horizontal

Magnepan DMW woofer Vertical

On the positive side, I do like the nuts used in BHK. It’s very difficult to properly tighten the bent at 30° heavy MIT forks with the x250 screws.

I think there is a solution. I will connect the loudspeaker cable diagonally wink