What would you ask BHK?


#1

Tomorrow, the 30th, I travel to Santa Barbara to interview Bascom on film. I have a list of questions, but perhaps some of you would like to add to that list?

I would be delighted to sort through suggestions and ask.


#2
Paul McGowan said Tomorrow, the 30th, I travel to Santa Barbara to interview Bascom on film. I have a list of questions, but perhaps some of you would like to add to that list?

I would be delighted to sort through suggestions and ask.


Paul I have not heard much talk about his thoughts on the Power supply design of the amp and preamp. Maybe he could go into some detail about what is unique about the PS in the amp and preamp if anything?

magicknow


#3

Also, AudioResearch converted their line to the 6H30 “supertube” from the 6922/6H23/E88CC that has more transconductance (~18,000 vs. 12,500) Granted there are few manufacturers of the 6H30 and very few sources of NOS left. But if it had been more available, would this tube have been considered for the BHK? Would there have been any advantage, sonically or otherwise?

–SSW


#4

If possible, I would like to know:

  • what added value will the BHK pre-amp bring compared to only using the BHK power amp?
  • what is so special about the MOSFET end stage? There are many good MOSFET amps on the market.
  • For a normal speaker load of 89db/8ohm: do the mono amps add value?

#5

I would like to know the slew rate of the new amplifier, and how it affects sonics/performance of the speakers.

In particular, does a fast slew rate help with less efficient speakers? In my mind (logically, not necessarily technically), does a fast slew rate help with dynamic impact of fast transients by getting less efficient drivers in motion more quickly?


#6

What is the best break-in procedure for this amp? The usual 400 hours of the XLO burn-in track at a modest volume will reduce the life span of the tubes by … hmm… 400 hours … And, BTW, how long will these tubes last?


#7

During Bascom’s talk, Arnie covers that most music is in the First Watt (the class A amplification threshold) and Bascom mentions that Class A amplification has drawbacks, particularly related to “dynamics”.

If elaborating, what characteristics does Bascom think of when mentioning the category of “dynamics”.

How do the BHK’s measure in these regards (however Bascom would nominate to measure them) ?

If Bascom doesn’t nominate slew rate and maximum instantaneous current as being useful measures of dynamics, it would be interesting to know slew rate (as already asked here today, and also elsewhere in the forum) and also the maximum instantaneous / peak current output.


I’m also really interested to know as much as possible along the lines of Adriaan’s first question. The advantages of using a Pre-amp / the BHK Pre-amp with the BHK’s (250 / 300’s).

At the moment, in my inexperienced (and therefore even more error prone mind) it’s almost as though a DirectStream DAC with a Pre-Amp passthrough for Phono might be easier, cheaper and more practical for folk using full range amplification (i.e. no crossover between Pre- and Power-).

Of course, if the Pre-amp has built-in crossover functionality, then, wow… what a fabulous way to extend from a single amp to multiple amps that would be. Just add more amplification boxes per additional crossover separation as budget allows.


#8

Thanks guys, these are all great questions I shall ask.


#9
Paul McGowan said Thanks guys, these are all great questions I shall ask.
Paul when will we get to see the video?

#10

Hopefully end of this week. I have about 3 hours of tape that now has to be edited down into usable chunks and posted.


#11

Do you meet the deadline for the Munich fare for the BHK?


#12

Yes, we will be there with BHK playing.


#13

Hi Paul,
do you have an approximate date about the distribution of BHK in Italy?

Many thanks
Matteo


#14

June will be the first dates we begin shipping BHK in quantities to other countries.


#15

Thanks Paul … I’ll prepare a space close tu my DirectStream … :-)


#16

One question from me;

Was the design of the BHK restricted by IP or patent rights tied to the work previously done?

So I guess what I am saying is that I reckon the design done for e.g. Constellation is owned by Constellation?

If this is a fact, could the BHK amps been done with an even higher performance if your hands were completely free?


#17

No, it wasn’t restricted because they are not the same. Similar, but definitely not the same.

I’ll let Bascom chime in on the second and, it’s something he covers in the videos that should be released today. But I would venture no.


#18

If it isn’t too late to ask Bascom about InterModulation Distortion. How does the BHK measure in this regard ?

I looked at the published specs; they include THD + N, but didn’t see anything on IMD.


Related, any measure (qualitative description) of the degree of Negative Feedback used in the BHK signature designs ?


With Thanks.


#19

Good questions.

Another one. I do not remember if it was answered anywhere: Are there any capacitors in the signal path?


#20

It’s too late to ask Bascom on the interview sessions but he does prowl these pages and will perhaps answer your question about IM if he sees it.

There is one set of capacitors in the signal path, placed between the tube output and the MOSFET amplification stage. These capacitors isolate the tube stage from the MOSFET stage. We use film and foil Rel Caps.