Review and Measurements of Lounge LCR MKIII Phono Amp

[March Audio]

Once I built a SRPP gainstage with 11HM7 pentodes wired as triodes. They are stratospherically high gm tubes. High perveance too. All looked good. one of the most linear sine waves I had ever seen coming from a tube. dynamics to burn. Ran music through it; sounded like cellophane. One of the most one dimensional sounds I had ever heard.

That's just a bit on the anecdotal side of things.

Can you show us the measurements?

 

[RayDunzl]

perveance

I had to look that one up.

Tough audience here, huh?

 

[Lounge Audio]

That's just a bit on the anecdotal side of things.

Can you show us the measurements?

I don't have them. I gave the data and schematic to the company that contracted me.

 

[Lounge Audio]

I had to look that one up.

Tough audience here, huh?

Perveance! A very important aspect of vacuum tube dynamic behavior. The audience to this thread are tough. The pursuit of outstanding audio is tough. It's a lot tougher than the numbers make it out to be. I love every minute of it.

 

[sublemon]

Nope. There is no such thing as 'bloated compressed sound." These are the things people imagine but have no basis in fact, engineering or audio research.

come one now. these are descriptive terms, perfectly valid. Even my digital audio player has an EQ function which results in "bloated compressed sound" every time it is used.

 

[Deleted member 2944]

"Bloated-compressed" is an oxymoron, isn't it?

This has turned into an hilarious thread.

Dave.

 

[Lounge Audio]

"Bloated-compressed" is an oxymoron, isn't it?

This has turned into an hilarious thread.

Dave.

The two can exist together in one sound. It can happen either in time domain or frequency domain. Usually it is a combination of both domains. A common thing is in frequency domain where the top end (speech frequencies on up) can sound very compressed. All the while the midrange can sound bloated. A lot of Motown and Bell Sound mastering has these qualities.

 

[NTomokawa]

I have to applaud Amir's tolerance of Lounge Audio's combative and belligerent attitude here.

Goodness, I love this forum.

 

[amirm]

A common thing is in frequency domain where the top end (speech frequencies on up) can sound very compressed.

Compressed? What does that mean? Twice you have mentioned this with no descriptor. As an engineer you need to be able to articulate audio issues precisely that has meaning to other engineers. You are resorting to lay audiophile notions to imply something is bad. As I keep saying, that doesn't fly here.

Compression in audio means either lossy bit rate compression (e.g. MP3) or dynamics compression. It is certainly not the former. If you mean the latter, then you need to state that and then explain how high frequencies with their miniscule levels can become "compressed."

 

[amirm]

come one now. these are descriptive terms, perfectly valid. Even my digital audio player has an EQ function which results in "bloated compressed sound" every time it is used.

As I just explained, terms have precise meaning in engineering. When used outside of that, it is random audiophile talk.

In your case, if you turn up the bass, then yes, you may get bloated but more likely distorted bass. These are the descriptors that need to be used: distorted, too much bass, etc. Not "bloated" by itself. We are not talking about stomach symptoms.

And then there is the issue of compressed. What are you hearing? That is what we want to know. Without that, we can't figure what is being talked about.

 

[amirm]

A lot of Motown and Bell Sound mastering has these qualities.

Mastering can indeed have such issues because it is created that way. It can have too much bass, too little highs, etc. That is not what we are talking about here when discussing a device.

 

[jackenhack]

Let's donate money and send him a copy of Douglas Self's book "Small Signal Audio Design."
You can even buy his RIAA amp from here. I bet you that it will both measure and sound better than the Lounge. And that's for less money, using no magic tricks, no silver wires and capacitors with magical properties.

Just three 2SB737 transistors per channel on the input, DC biased using a TL072 through a NE5534 and finally NE5532 opamp. The amplifier has an RIAA equalisation accuracy of ±0.1dB. Just by applying engineering and measurements (look at the AP logo at the top of the graphs.)

Which gives me an idea, @amirm if I order a ready-made unit for $290 and send it to you, would you like to test it? I'll pay for the return cost as well.

 

[amirm]

Which gives me an idea, @amirm if I order a ready-made unit for $290 and send it to you, would you like to test it? I'll pay for the return cost as well.

Yes, would love to measure it.

 

[jackenhack]

Yes, would love to measure it.

I'll DM you.

 

[Lounge Audio]

As I just explained, terms have precise meaning in engineering. When used outside of that, it is random audiophile talk.

In your case, if you turn up the bass, then yes, you may get bloated but more likely distorted bass. These are the descriptors that need to be used: distorted, too much bass, etc. Not "bloated" by itself. We are not talking about stomach symptoms.

And then there is the issue of compressed. What are you hearing? That is what we want to know. Without that, we can't figure what is being talked about.

Think about this, what happens when audio is passed through a lossy component? Take an average electrolytic capacitor without bias voltage for example. It’s not too bad when the current passes in the direction marked on the polarity of the capacitor. But what happens when the current goes in reverse? The dissipation factor shoots through the roof! It can get so bad that the capacitor can get physically warm to the touch. Audio current is getting converted to heat. It’s level dependent. Distortion goes up (That’s the bloating you say does not exist). But ALSO if audio current is getting converted to heat something has to suffer that is level related. Compression anyone?

 

[SIY]

What's the current through a capacitor at the output voltage and termination levels we're talking about here?

Let's say 1V out and a 10k load for a general case. That's 100 microamps max. If you have heating, you need a new cap.

edit: Let's convert that to power. At the 100 uA current, if the ESR were ridiculously high, let's say 10 ohms, the voltage across the cap is 100uA x 10/(10 + 10,000) = 0.09 microvolt. So the max power is 0.09 x 1uA which is 90 nanowatts. Yeah, we ought to worry about that level of power modulation.

 

[NTomokawa]

Signals "pass through" capacitors now? Right. Or are you trying to say that micro- if not nano-amps of leakage current "compresses" the audio signal?

Here's a better idea: DC-coupling all the way, i.e. no capacitors in the signal path. There. Tell me what else is "compressing" the audio signal.

 

[amirm]

Think about this, what happens when audio is passed through a lossy component? Take an average electrolytic capacitor without bias voltage for example. It’s not too bad when the current passes in the direction marked on the polarity of the capacitor. But what happens when the current goes in reverse? The dissipation factor shoots through the roof! It can get so bad that the capacitor can get physically warm to the touch. Audio current is getting converted to heat. It’s level dependent. Distortion goes up (That’s the bloating you say does not exist). But ALSO if audio current is getting converted to heat something has to suffer that is level related. Compression anyone?

Distortion is measurable. I thought you were talking about stuff that can't be measured. In the case of your amplifier, there is copious amount of distortion so not sure what you have accomplished if distortion is a bad thing (which it is).

That aside, who says distortion is the same as "bloating?" What is bloating? If this is non-linearity creating harmonic distortion, then it will accentuate highs. How is that bloating?

I say again, please don't throw these things at us. We are educated folks here and can read through hyperbole easily.

 

[Lounge Audio]

What's the current through a capacitor at the output voltage and termination levels we're talking about here?

Let's say 1V out and a 10k load for a general case. That's 100 microamps max. If you have heating, you need a new cap.

That heating cap was an extreme case in a power amp. Just to clear it was not getting anywhere near hot, just warm to the touch. It was 25 years ago at the company I worked at called Alesis Studio Electronics. All that data was theirs so I don't have it. The tests performed were not targeting the capacitor per se, the amp was being tested globally.

 

[Lounge Audio]

Distortion is measurable. I thought you were talking about stuff that can't be measured. In the case of your amplifier, there is copious amount of distortion so not sure what you have accomplished if distortion is a bad thing (which it is).

That aside, who says distortion is the same as "bloating?" What is bloating? If this is non-linearity creating harmonic distortion, then it will accentuate highs. How is that bloating?

I say again, please don't throw these things at us. We are educated folks here and can read through hyperbole easily.

A search on Audio Science Review brings up multiple entries of the word "bloated"