Does the amp have 20A electrical plug or standard?
I don’t remember that being brought up, but it looked like a standard electrical plug. I’m sure those in the know will correct me if I’m wrong.
15 amp…
1 Like
In the BHK600 manual, I don’t like the phrase “stealing radios from the dump”. It doesn’t flatter Bascom. Recalling my childhood dump picking 68 years ago, I suggest the term “scrounger”. I was one who looked for and found free parts: electronic and mechanical.
2 Likes
Probably intelligent oversight - temperature, DC offset, etc.
1 Like
The 600’s shipped today, I will keep you updated. As for the PS Uplink port, my guess is this is what most of you think, a system communication/ diagnostic tool for the future. The USB port for software upgrades seems to be of greater utility for fixes and improvements.
7 Likes
And…you would be wrong.
3 Likes
I read in the PS Audio BHK 600 manual, there is a third (new) tube. A rectifier EZ81/6CA4.
Question: Why has PS Audio added this (absent in BHK 300), and how does it change the sound of amp (BHK 300 Vs BHK 600)?
Peter was incorrect. That rectifier tube has a HUGE impact on the sound and we spent a great deal of time getting the right one.
That’s @Paul response from the video that was posted on the new amplifier.
2 Likes
A rectifier tube has advantage over a rectifier bridge (four diodes) because there’s no “switching” noise. Every time a diode goes forward/reverse (AC wave goes from positive to negative phase), it adds noise to the power supply. This is why you will usually see some 60Hz and 120Hz (harmonic of 60Hz) noise in a component’s noise measurements. Generally this is called “mains hum”.
How much mains hum a component has and is it audible depends on a myriad of things. You may be better off with tube rectification or you may not.
5 Likes
Tube vs. Solid State Rectifiers for Tube Amplifier Power Supplies (bandwidthaudio.com)
A little bit of deeper dive for those inclined
My experience with tube rectification is limited to my preamp which does what it is made to do switch AC to DC and is outside of the signal path
I have rolled this tube EZ-81 a bit and did not find notable differences but my preamps designer recommended Mullard EZ81 so thats what I stick with
That said, I’m sure the designer choose tube rectification for a reason maybe a bit of smoothness to the DC? IDK
Not an electrical Engineer, but I did stay at a Holiday Inn once, like 6 years ago, so there’s that…
Best,
-JP
3 Likes
My previous DAC, a Waversa VDAC used a tube rectifier. A 6X4, and it made a considerable change to the music. I settled on Mullard manufactured tubes after rolling half a dozen. I’d say design is the biggest factor as to whether a rectifier will affect sound.
1 Like
Following that, will this design flow down to the BHK300 mk2 and BHK250 mk2? For those of us that doesn’t want to deal with the weight, don’t have the space, or money for the 600.
Do they need it? A tube rectifier is not a magical device that makes rainbows. If it was, all hifi components would use it.
3 Likes
Not sure about your logic. That’s like saying a massive power supply in an amp makes magic so if that’s true all amps would have it. Even amps that can’t afford it.
?
Fact is, tube rectifier make far less noise and harmonics as they work their diode magic. In our case the rectifier produces a pure sine wave, something quite difficult (if not impossible) for a solid state rectifier with it’s hard on/off nature. Tubes are gentler with audio as well as AC voltages. Tube rectifiers are expensive and not that easy to design. Using solid state rectifiers is a lot simpler and cost effective.
That said, one might wonder why big and expensive amps of all kinds don’t use vacuum tube rectifiers. The answer is simple. It’s the same reason all amps don’t use tubes. Or the same circuits. Personal choice for the designer.
4 Likes
My logic is very simple:
If your SS power supply is very quiet (let’s say 60Hz is 120db down), then what benefit is the tube rectifier?
I would say it would be more cost effective to buy a set of BHK 600’s.
Am I correct in that the tube rectifier in the BHK 600 is for the front end stage only and solid state diode bridges are employed for the rest of the amplifier?
1 Like
@Paul the unboxing video was enjoyable. Is there going to be a detailed product video going over the new amps and get a little more into the new features like the rectifier tubes? Thank you
The extensive owners manual goes pretty deep on features and applications and the web site product guide is a good basic summary of what’s under the hood. Description of the rectifier tube is an example of this. This design decision, albeit uncommon and has its pros and cons, is what we want our circuit designers to do…challenge convention, even with old school implementation. I have always been resistant to the vagaries of tubes. Not any more. And if Bascom says he needs a third to make it even better, I trust that. Units in the field will be its judge and jury.
4 Likes