The Stax Thread III

[mulveling]

The power consumption is interesting because -- among the amps with a direct drive class A topology -- a LOT of power is required to facilitate both a high clipping limit and wide bandwidth. Sure, a (static) chunk of that goes into the heaters with tube amps. Easy to calculate. The power consumption can tell you roughly where it falls among peers. Below a certain threshold, it's either underpowered and/or using a different topology. Don't read too much into it, but don't dismiss it as useless info either.

I can add another data point: hev90 clone, KG "Balanced" version draws 60 Watts from the wall (as per Kill-a-Watt). It's a constant draw no matter load, because class A. The ECL86 plates are now adjusted to ~ 300V (thanks to Dr. Gilmore for the help). The tubes are like EL84 but also including a single 12AX7 triode in each envelope. It's definitely not as powerful as the bigger amps: BHSE, KGSShv, Carbon, T2 etc. I can get this amp to clip (with complex music - not test signal) on Omega-class (007, 009, ES1a) headphones. Yes, it's loud (I listen loud), but still at a much lower threshold than you'd have with any dynamic driver system. Electrostats are hard to drive because of the voltage requirements. They're pretty efficient transducers once you get the power into them (at required voltages) but the challenge is on the amp side (because of the high voltages involved). Per-volt, electrostatic forces are extremely weak compared to coil & magnet.

 

[alota]

One question, please: the amplifiers based on Dr. Kevin Gilmor's design accept rca input? In affirmative case, Are there any performance differences? Thanks in advance

 

[timb5881]

The power consumption is interesting because -- among the amps with a direct drive class A topology -- a LOT of power is required to facilitate both a high clipping limit and wide bandwidth. Sure, a (static) chunk of that goes into the heaters with tube amps. Easy to calculate. The power consumption can tell you roughly where it falls among peers. Below a certain threshold, it's either underpowered and/or using a different topology. Don't read too much into it, but don't dismiss it as useless info either.

I can add another data point: hev90 clone, KG "Balanced" version draws 60 Watts from the wall (as per Kill-a-Watt). It's a constant draw no matter load, because class A. The ECL86 plates are now adjusted to ~ 300V (thanks to Dr. Gilmore for the help). The tubes are like EL84 but also including a single 12AX7 triode in each envelope. It's definitely not as powerful as the bigger amps: BHSE, KGSShv, Carbon, T2 etc. I can get this amp to clip (with complex music - not test signal) on Omega-class (007, 009, ES1a) headphones. Yes, it's loud (I listen loud), but still at a much lower threshold than you'd have with any dynamic driver system. Electrostats are hard to drive because of the voltage requirements. They're pretty efficient transducers once you get the power into them (at required voltages) but the challenge is on the amp side (because of the high voltages involved). Per-volt, electrostatic forces are extremely weak compared to coil & magnet.

Wow ecl86 I have an amp that uses them. They are on the rare side and expensive if you can find them.

 

[bearFNF]

One question, please: the amplifiers based on Dr. Kevin Gilmor's design accept rca input? In affirmative case, Are there any performance differences? Thanks in advance

Simple answer is: "Yes, but it depends on which amp/energizer and how it's built" for the first question, and for the second question, the answer is: "It depends".

Balanced option will typically offer more power and control of the headphones in comparison to the single-ended output, But it all depends on how the amp/energizer is built and the rest of the system. YMMV IMHO and all that.

 

[mulveling]

Most

One question, please: the amplifiers based on Dr. Kevin Gilmor's design accept rca input? In affirmative case, Are there any performance differences? Thanks in advance

Most of the KG-design electrostatic amps have a differential input stage (KGSShv, KGST, KGGG, BHSE, Carbon, DIY T2 etc). This means they can accept either single ended or balanced input signals with no performance penalty or preference either way. You can even feed a single-ended signal into its XLR inputs (e.g. via RCA female -> XLR male adapters) with no problem (you definitely can't do that with some "balanced" amp designs). Many of the KG amp builds only have XLR inputs (out of builder's choice for simplicity), and the correct procedure is just use these adapters with single-ended sources. I've personally done this with phono stage sources on KGSShv, KGST, BHSE, and DIY T2 -- it sounds great, and definitely doesn't cede any performance to a balanced DAC.

 

[alota]

Most of the KG-design electrostatic amps have a differential input stage (KGSShv, KGST, KGGG, BHSE, Carbon, DIY T2 etc). This means they can accept either single ended or balanced input signals with no performance penalty or preference either way. You can even feed a single-ended signal into its XLR inputs (e.g. via RCA female -> XLR male adapters) with no problem (you definitely can't do that with some "balanced" amp designs). Many of the KG amp builds only have XLR inputs (out of builder's choice for simplicity), and the correct procedure is just use these adapters with single-ended sources. I've personally done this with phono stage sources on KGSShv, KGST, BHSE, and DIY T2 -- it sounds great, and definitely doesn't cede any performance to a balanced DAC.

Thank you. I ask because my dac, built by a friend of mine, has two chip tda 1541 but it is single ended with 2v rms. This dac works very well with 009

 

[573531]

SMH. If there was no performance difference to be gained, balanced cable transmission would have never been invented. It’s amazing how much misinformation is let to fly on this thread.
You will be better served asking chatgtp such questions than trusting someone who already admitted “I’m definitely not one of the in the know guys”. But still proceeds on.

 

[SolarCetacean]

SMH. If there was no performance difference to be gained, balanced cable transmission would have never been invented. It’s amazing how much misinformation is let to fly on this thread.
You will be better served asking chatgtp such questions than trusting someone who already admitted “I’m definitely not one of the in the know guys”. But still proceeds on.

Recall that Stax-style electrostatic headphones are inherently balanced; the diaphragm is driven by two stators on opposite sides of it - one stator has the normal signal and the other has the inverted signal to drive the diaphragm in a push-pull fashion. All Stax amps are internally balanced differential by necessity. The input signal has to be converted to a balanced signal regardless of input type. Thus, there's no real performance to be gained from balanced transmission. Sure, true balanced means noise rejection and a doubling of input voltage, but the amp itself doesn't really care about those things. It's not like some amps which are balanced separate and a single-ended input means half of the amp isn't doing work.

 

[alota]

SMH. If there was no performance difference to be gained, balanced cable transmission would have never been invented. It’s amazing how much misinformation is let to fly on this thread.
You will be better served asking chatgtp such questions than trusting someone who already admitted “I’m definitely not one of the in the know guys”. But still proceeds on.

despite electrostatic amplifiers and headphones, in the past i had all my stuffs balanced: amplifiers, headphones and sources. today I changed my mind about many things and many times the balanced is just an extra expense. I listen better with simple unbalanced objects

 

[573531]

Recall that Stax-style electrostatic headphones are inherently balanced; the diaphragm is driven by two stators on opposite sides of it - one stator has the normal signal and the other has the inverted signal to drive the diaphragm in a push-pull fashion. All Stax amps are internally balanced differential by necessity. The input signal has to be converted to a balanced signal regardless of input type. Thus, there's no real performance to be gained from balanced transmission. Sure, true balanced means noise rejection and a doubling of input voltage, but the amp itself doesn't really care about those things. It's not like some amps which are balanced separate and a single-ended input means half of the amp isn't doing work.

and what about the whole way before the signal reaches the amp board? Especially those chunky transformers just can’t wait to induce their 120 or 100hz hum into your signal, leave alone problems with ground loop and other EMI

 

[ESL-1]

and what about the whole way before the signal reaches the amp board? Especially those chunky transformers just can’t wait to induce their 100hz hum into your signal, leave alone problems with ground loop and EMI

Not my experience with five Stax amps currently in my group along with the highly recommended Eksonic Aeras.

 

[573531]

Not my experience with five Stax amps currently in my group along with the highly recommended Eksonic Aeras.

Yeah, that’s ok, some people are also totally satisfied with apple earbuds.

 

[ESL-1]

Yeah, that’s ok, some people are also totally satisfied with apple earbuds.

I do not understand the meaning or point of your response. Please clarify the meaning so we know what you are actually stating or alluding to.

I would appreciate that.

 

[SolarCetacean]

and what about the whole way before the signal reaches the amp board? Especially those chunky transformers just can’t wait to induce their 120 or 100hz hum into your signal, leave alone problems with ground loop and other EMI

Noise rejection is only a practical advantage if noise is a problem. If it's not a problem in the setup (e.g. the problems are mitigated elsewhere in the chain), then there's no practical benefit to running balanced. Balanced has its place and its use like in professional audio, but it's more of a nicety in most home Hi-Fi use cases than a strict upgrade. Nevertheless, most of the higher-end electrostatic amplifiers have balanced inputs already, so the option is already there. The original point of this discussion before you sidetracked it is that someone should not feel pressured to buy a balanced DAC to feed their estat amp, because the signal is handled in a balanced differential manner by the amp, regardless of the source. Going balanced will be for the noise rejection and increased input voltage rather than any performance difference stemming from the amp's internal topology.

Frankly, I'm getting tired of trying to provide information to you. You are relentlessly hostile to anyone who tries to inform you of the nuances of electrostatic headphones and the design of their amps. Do you even have estats yourself, or any interest in trying them, or are you just here to be an ideologue and stir up crap?

 

[573531]

Noise rejection is only a practical advantage if noise is a problem. If it's not a problem in the setup (e.g. the problems are mitigated elsewhere in the chain), then there's no practical benefit to running balanced. Balanced has its place and its use like in professional audio, but it's more of a nicety in most home Hi-Fi use cases than a strict upgrade. Nevertheless, most of the higher-end electrostatic amplifiers have balanced inputs already, so the option is already there. The original point of this discussion before you sidetracked it is that someone should not feel pressured to buy a balanced DAC to feed their estat amp, because the signal is handled in a balanced differential manner by the amp, regardless of the source. Going balanced will be for the noise rejection and increased input voltage rather than any performance difference stemming from the amp's internal topology.

Frankly, I'm getting tired of trying to provide information to you. You are relentlessly hostile to anyone who tries to inform you of the nuances of electrostatic headphones and the design of their amps. Do you even have estats yourself, or any interest in trying them, or are you just here to be an ideologue and stir up crap?

How can you know if noise will or won’t be a problem for the one who asked the question?