BHK Beta Tester Reports

Audio Components Amplifiers
201
patentpending said OK guys, here's my first post about the BHK monos!

I have to be honest, however. It didn’t take me more than a couple of hours of initial listening before I became impatient enough to roll the gold lion tubes with some NOS Telefunken E88CC tubes that I’ve had here waiting for the amplifiers that I bought from Kevin at Upscale Audio (FYI at Telefunken E88CC / 6922 – Upscale Audio). I had read several reviews about these tubes from a variety of sources, and thought that they’d be good to try.

For someone that is as addicted to tube rolling as I am, and probably will try a few different tubes, swapping the tubes was a very easy proposition. The design of the monoblocks makes their access very straightforward using just a phillips screwdriver to unlatch the small metal covering. I found that the tube sockets in the monoblocks appeared to be very well made. The tubes easily came out, and the E88CC tubes went in. To my ears, this was a very noticeable improvement in sound quality (I can not overemphasize this, but take my opinion for what it is worth). So pleased as I was with the improvement, I went back to some initial listening.

Patentpending,

I bought some of the Telefunken tubes from Kevin 5 months ago in anticipation for the BHK but haven’t put them in yet. To my horror I’d discovered a guy at JacMusic ( E88CC Telefunken NOS, or used tubes and recently updated at HALL OF SHAME, PICTURES OF FAKE TUBES ) who also bought “NOS” tubes from eastern Europe that had similar markings with the non-standard gold tube ink replete with misaligned letters. Heck, even one of the ‘date’ codes matched one of the tubes I bought. He had bought his tubes earlier than Kevin did, so I suspect the sellers found some used Telefunken tubes, put new markings on them as the original Telefunken ink was notorious for wearing off, put them in new boxes and sold them as NOS. That guy’s tubes tested out as very lousy. Word got out. I suspect what really happened is that in the first batch the sellers didn’t check the tubes for performance, and in Kevin’s batch they weeded out the duds.

Trouble is, they test well, according to Kevin. So are they fakes? Used? New/rebranded? (In the second link, above, it shows how the Telefunken symbol on the bottom of the tube can be faked with a laser)

I dunno. They are most likely fakes, but good enough to trick even Kevin. I’m waiting to get to 500 hours on the BHK before I do anything.

202

SSW, don’t those TFKs have the raised diamond on the bottom, between the pins?

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tony22 said SSW, don't those TFKs have the raised diamond on the bottom, between the pins?
Yes they do, however, as noted on the jacmusic site at http://www.jacmusic.com/nos/im…..ges/Fakes/ there is a way to fake the diamond with a laser. So it's possible they're fakes.

However, we know Kevin tests his tubes and they perform well, so at least the ‘fake’ tube will at least work OK and not like the crappy ones the guys got in 2008 in the first batch.

–SSW

204

Hi everyone,

I finally was able to have the Richmond Audio Society (Virginia) over to listen and compare the BHK and Audio Research D-150 just before my son got married this past weekend. I am sorry for it being so long since my first post on July 18th. Had a few things happen, the most serious (no injuries) was I blew out the tweeter's of the 20.7's playing the Giant Drum selection on the Beta test disc PS Audio sent.

I previously had gone to 107dBc and stopped. I tried again a couple of days later and max reading was 109.8 dBc. Right after the loud drum section at 4:50 + is a percussion crash of an enormus level that melted the tweeter, but not the fuse. So I ordered up new tweeters and waited arrival. And canceled the RAS review meeting.

After completed packing up of the house putting it on the market, selling it in 3.5 weeks, getting ready for the wedding, RAS met for October.

All the digital equipment is on 24/7 and Tube equipment was on at 9:00am for 2:00pm meetup. I turn it on every day to keep system in shape, even if I can't stay in room.

We started out listening to Rosanne Cash's latest album (LP The River and the Thread) on the ARC D-150. Her voice and the acoustic instruments and other instruments sound really really good. The midrange is strong on D-150 and very smooth. We then switched to the BHK. The whole stage opened up to be able to hear so clear the location of the players. Rosanne's voice was more real than the D-150 and not as soft. We then switched to the PS Audio CD. Still on BHK.

The first selection is Shelby Lynn “Just a Little Lovin'”.

The tick,boom tock is just right there. The voice is so rich in tone. Really good. The BHK lets you hear it all. Low to High. We listened later to this on the D-150. A case was made by some members of RAS, that some will like the smooth D-150 on this selection and the Rosanne Cash songs we heard. I like both. Later I listened to the Shelby Lynn on LP with the BHK. Wow.

The next selection Requiem: Agnus Dei.

The BHK maintains the separation of Voices (300) and instruments and soloist so beautifully. The D-150 turns bass into one note hum and muddies up chorus a little, but is smooth. The BHK presented a big Soundstage.

The next selection is “Within” by Daft Punk.

This requires a full frequency amplifier that the BHK delivers. The Bass and Cymbals with great sheen are all there. The BHK gives a natural sound to everything you play. Here again I did the LP later. Wow again.

The next selection is “Alfie” by Burt and Hal.

There is a punch edit that the BHK allows you the hear but the D-150 not so much. That may be a good thing on some selections. The edit is not even timed right throwing off the music flow.

The last selection is the Giant Drum. Not my favorite! Listen at low level to hear what is on the disc before you turn it up. We listened at a low level to hear the point where the tweeters gave their life. This point also tripped the protection circuits when the tweeters melted.

We listened to many selections over the next hours and everyone likes the BHK and some like all tube amps also. The BHK is way beyond the D-150, but it is a 1973 piece (but has new caps etc.). I am looking forward to getting a BHK preamp to see how the ARC SP-10 has filtered what I am hearing from the BHK 300. Need to try other tubes in bHK also next.

I have to say that the Directstream and Yale sound the closest to my LP's that I have ever heard CD's sound. Ted has designed a real winner. I can listen to my CD's that I don't have on LP and enjoy! I have now listened to some orchestra selections with and without Piano or Violin. The BHK just gives so much power to the orchestras and yet the low levels are so clear.

The BHK is just a wonderful instrument on its own. BHK, Arnie and Paul. Thank you for creating this!

Tomorrow Oct 1st the two musicians in the office are coming to compare the BHK to the D-150. We have been so busy at the office (a good thing for architects) we are just getting together since the tweeter meltdown messed upeverything earlier.

I am off to the RMAF to listen to the BHK preamp Friday. See you in the PS Audio room if anyone wants to talk BHK.

Dave

205

Great report!! Thanks!!

206

+1. “Melted tweeters”–yikes! Makes me wonder if they specified the right values for the fuses.

207

Hi back again,

The two musicians came over during lunch today as planned finally. Everything on all morning so ready to listen to.

One had thought the D-150 had a good midrange that was really good (and it is good).

We started off on the D-150 with the Daft Punk “Within” on LP. I asked them to notice the bass and cymbols in particular. We switched to the BHK and wow there was a better cymbol with more highs and a stronger presentation. The midrange was still there very strong and more than a little better than the D-150. The one agreed hearing both one after the other that the BHK just offers so much more, with a better midrange. We then switched to the CD “Within” selection. They thought the LP was much better than the CD. Just more information (I will add with slightly less tight bass) on the LP.

Maybe I need to hear some DSD or other Hi Res files to see how they compare to an LP. I am hearing all this through the “Filter” of the SP-10. I can’t wait to have the BHK preamp and see what it does. If the BHK preamp is as improved over the SP-10 as the BHK Mono is over the D-150, we will be listening to something really special. I can’t hardly wait. And I still have to try other tubes in the BHK Mono (Gold Lions now). I use Telefunken’s in the SP-10 low-noise locations (a big plus).

A quick comment on preamp or no preamp (or tuner) with the DS. Has always been better with the active preamp for me . Sound has more drive(passive preamp has no drive either). exactly what causes more drive other than to say a gain stage in preamp, I have no answer. I just know it sounds better.

Already had a friend send me pic of the PS Audio room at the RMAF. Looking forward to hearing the YG’s. See you there tomorrow afternoon.

Next report after I move to new larger room, where speakers will be spread wider and nothing behind as I have now. Hoping that it is better, but no plaster walls.

Dave

208

Interesting thing I can’t explain. (Oh, yeah, like I can explain the rest 21_gif)

When I received the BHK250 in May, the room temperature was around 25C. After several hours the BHK fins were very hot. After several days, I could not keep my palm on them for longer than a couple of minutes.

After I returned from vacation this fall, the ambient temp dropped to around 17-18. When I switched the amp on, nothing happened. Long story short, the bottom right fuse blew, it turned out that the BHK250 was shipped with a 1A fuse instead of 5A (I think the BHK fuses deserve a separate thread). I replaced it with a similar 1A (I did not have anything “fatter”) and it blew again. Next day I bought some stock 5A fuses and the amp came to life. But… It’s barely warm now. Is it normal or something else is broken? Also, why was the amp working with that 1A fuse before? Is it just the ambient temperature? Is it possible to test something “in the field”?

209
Alekz said Interesting thing I can't explain. (Oh, yeah, like I can explain the rest )

When I received the BHK250 in May, the room temperature was around 25C. After several hours the BHK fins were very hot. After several days, I could not keep my palm on them for longer than a couple of minutes.

After I returned from vacation this fall, the ambient temp dropped to around 17-18. When I switched the amp on, nothing happened. Long story short, the bottom right fuse blew, it turned out that the BHK250 was shipped with a 1A fuse instead of 5A (I think the BHK fuses deserve a separate thread). I replaced it with a similar 1A (I did not have anything “fatter”) and it blew again. Next day I bought some stock 5A fuses and the amp came to life. But… It’s barely warm now. Is it normal or something else is broken? Also, why was the amp working with that 1A fuse before? Is it just the ambient temperature? Is it possible to test something “in the field”?


First of all, for a constant amount of power dissipated in the head sinks, the heat sink temp is going to rise above the ambient by some amount. In the case of the ambient of 25 deg C or 77 deg F, the heat sinks will get hot. In my house in the summer it sometimes gets up to about 85 deg F and those heat sinks on my BHK-250 get close to 50 deg C or 122 deg F. That is quite hot! Now in your case when the ambient temp was down to 17-18, the heat sinks will not get as hot as when the ambient temp was 25 deg C.

Regarding fuses, I believe PS Audio has increased the size of the 1A fuses. No big deal, it just needs to be a bit bigger. The fact that it worked with the original 1A fuse and then it didn’t is just one of those mysteries we have to live with. Perhaps the fuse was getting tired and the particular turn on that blew it might have been such that the inrush current into that supply peaked out a little higher than normal. Perhaps the AC line voltage was up a bit over normal.

210
BHK said
Alekz said it turned out that the BHK250 was shipped with a 1A fuse instead of 5A

Regarding fuses, I believe PS Audio has increased the size of the 1A fuses. No big deal, it just needs to be a bit bigger. The fact that it worked with the original 1A fuse and then it didn’t is just one of those mysteries we have to live with. Perhaps the fuse was getting tired and the particular turn on that blew it might have been such that the inrush current into that supply peaked out a little higher than normal. Perhaps the AC line voltage was up a bit over normal.


I just got a BHK-250, 120 Volt and it has a 1.6 amp fuse. The remaining fuses are 10 amp.

From the manual:

120vac Countries

1 - 1.6 amp slow blow H-rated 5x20mm

1 - 10 amp slow blow H-rated 5x20mm

The only model that shows a 5 amp fuse is the 230 volt model.

230vac Countries

1 - 1 amp slow blow H-rated 5x20mm

1 - 5 amp slow blow H-rated 5x20mm

The labeling on the back of the amplifier shows the fuse value based on voltage that the amplifier runs on. Be sure that you use the correct fuse based on your AC voltage.

211

Bstanwick, Alekz has a 230VAC version, hence the 5A fuse.

Edit: Now that I think of it, someone must have made a mistake. The other fuse is 1A, I doubt they were both initially 1A fuses. Going from 1A to 5A fuse is a pretty significant change, seems very odd…

212
BHK said

Regarding fuses, I believe PS Audio has increased the size of the 1A fuses. No big deal, it just needs to be a bit bigger. The fact that it worked with the original 1A fuse and then it didn’t is just one of those mysteries we have to live with. Perhaps the fuse was getting tired and the particular turn on that blew it might have been such that the inrush current into that supply peaked out a little higher than normal. Perhaps the AC line voltage was up a bit over normal.


The BHK250 is connected to the PPP, so the voltage should be stable. When it was cold, I blew two fuses (one by one), so I would say that the current inrush is different depending on how cold the gear is. Sounds pretty much scientific

213

Oh, Bascom, while we are on the fuse subject, could you please be so kind to shed some light on which fuse protects what? For example, the one at the bottom right - is it the tube stage power supply, of the transistor one, etc? I got strange effect when was troubleshooting/replacing the fuses. Either the whole amp was dead (but when I removed one of the high current fuses, the corresponding LED turned on, so some electricity was going through the other path), or everything was up (at least it looked like it), but there was no sound.

And on a bit different subject - which fuses would you recommend to upgrade first - the ones at the bottom? Or in other words, which fuses affect the sound most.

214
Alekz said When it was cold, I blew two fuses (one by one), so I would say that the current inrush is different depending on how cold the gear is.
The amps may have bleeder resistors connected in parallel with the output of the high-voltage power supply circuit to discharge the power supply's filter capacitors when the equipment is turned off. This is a safety feature, but does increase inrush current if the amp sits for a while.
215
Alekz said Oh, Bascom, while we are on the fuse subject, could you please be so kind to shed some light on which fuse protects what? For example, the one at the bottom right - is it the tube stage power supply, of the transistor one, etc? I got strange effect when was troubleshooting/replacing the fuses. Either the whole amp was dead (but when I removed one of the high current fuses, the corresponding LED turned on, so some electricity was going through the other path), or everything was up (at least it looked like it), but there was no sound.

And on a bit different subject - which fuses would you recommend to upgrade first - the ones at the bottom? Or in other words, which fuses affect the sound most.

The smaller fuse on the right is for the smaler power transformer that powers the tube B+ and heater supplies. The larger fuse to the left is for the large power transformer the supplies the solid state output amplifier.

As to fuse upgrades, I really don’t know. One could say the output stage fuses might be the most important as they are closest to the ouput stage. On the other hand, the AC power fuses are at the beginning of the process and they may be the most important. Any more wisdom on the subject?

216

I’ve found out that the fuses were confused: the 5A one was inserted into the 1A holder, and 1A fuse into the 5A slot.

Hm… “confused fuses”. “Confuses” 21_gif

217

I’ve been using my BHK 250 for almost a year now and have been very happy with it. The sound is wonderful and it mates nicely with my DS, no preamp needed (at least for digital, still trying to get a turntable through the NPC to equal the DS). Over that space of time I have had zero problems with it and only one “observation”. That observation is about 40-45 minutes after turn on from the stand by state I get a distinct click like a relay is opening or closing. The sound is almost the same as the click when the amp comes out of the stand by state, which presumably is a relay, but the volume doesn’t seem as consistent. Sometimes it’s a softer click and sometimes it’s a louder click. This loudness difference could be real or tied to my state of awareness on that particular day. I have never noticed a change in the sound after the click so I’m not overly concerned with it, but my curiosity wants to know what it is. I’ll also add that I don’t recall this happening when I first got the amp, but I have noticed it doing this for several months. I don’t recall anyone else pointing this out and I didn’t see anything in the manual on it. If anyone else has heard it please post, otherwise I hope Paul or Bascom will solve the mystery!

218

The heatsinks on my unit “click” when they get to a certain heat - is that what you’re hearing? I can’t think of any relay inside that should be activating.

219

I bet this is it.

Sometimes the heat sinks on my SS amps make a ringing ping, in addition to clicks. My tube amps make all sorts of clicks, pops and other pleasing noises when heating up and cooling down. EL34 power tubes are particularly talkative.

220

The heat sinks could be it, the odd part is it sounds just like a relay. The other thing is it only does it once, perhaps only one heat sink is making the noise? I should try sitting next to the amp at the appropriate time to see I can discern where it is coming from.