EAR Yoshino 834L Deluxe Preamp Review

[Rottmannash]

For me, it's like this:

My technical curiosity does not necessarily have anything to do with nostalgia. I started 20 years ago again to rebuild old phono preamplifiers with tubes, based on classical circuits from ELAC, PE, Shure, Dynaco, Marantz, RCA, etc. simply because I wanted to hear how they sound when I build them new with better components from today and quieter power supplies. I had a lot of fun with that and over time I came up with a circuit that I've been circling around, optimizing and building in various forms a many times since then. Some of these preamps are still in use in the systems of audiophile friends. And yes, it's HiFi.

But wouldn't it be fair to say it's only hifi because you've optimized these devices over and over with better components?

 

[computer-audiophile]

But wouldn't it be fair to say it's only hifi because you've optimized these devices over and over with better components?

Of course, that's true to a certain extent. The S/N improves most clearly when the power supply is made more elaborate. My favorite circuit concerning phono preamplifiers is the SHURE model M65 from the sixties. It was the last design of SHURE with tubes, after that they went on with semiconductors.

The original device:

An early revised version of mine 20 years ago looked like this. I had made a private (non commercial) small series of it for friends:

 

[lashto]

Take a look at for example Topping A70 Pro balanced headphone amplifier and preamplifier. And compare it to this EAR-amplifer. In the Topping we see vanishingly low distortion. EAR on the other hand has in comparison very high harmonic distrtion

another "point of failure". I guess that's the source of those "distortion factory" comments. Which are quite wrong (as in wrong math)

For simplicity let's round the numbers a bit: Tube-amp (60dB SINAD) vs. SS-amp (120dB SINAD)
Most ASR members/readers will see those numbers and think: 60dB vs 120dB .. uhaaa, that tube-thing will double my distortion. It's a "distortion factory", go away.
Some others (unfortunatly not as many as expected) know a few things about math/engineering. 60dB=0.1%, 120dB=0.0001%. The tube-thing actually increases distortion >1000x. Gigantic distortion factory .. un-acceptable, incredibly bad, monstruosity ... die tubes, die!

Hand-up if you think the above math is correct. And another hand-up if you think it is the right/relevant math for this case.

Hint: it is not
In spite of that eye-watering 1000x factor, there is no "distortion factory" and the diff between the tube-amp and the ss-amp is quite probably inaudible. To be more precise, it could be anywhere between inaudible/audible-bad/audible-good..

 

[lashto]

... but also high IMD. In addition, the channel separation is poor.
... the engineering conclusion must be that this amplifier performs poorly.

both IMD & crosstalk are also in ~inaudible territory. And good for a tube device.
This EAR actually measures pretty well for its category (tube-preamps).
And I do not think it's fair to compare it numbers-to-numbers with SS-preamps. Same as it's not fair to compare phono-preamps and line-preamps.

All of you who dismiss the "engineers'" criticism...

I do not "dismiss" it, I just think it's unfair. It's a personal oppinion, noone needs to agree.

what is your argument why one should spend ten times more money on an EAR preamp compared to, for example, a Topping A70?

no idea, I don't buy or recommend this kind of stuff. Should be the same reason why people buy swiss watches for $10K. Or any other "male jewelry". Their money/taste and none of my business.

 

[Postlan]

I honestly don't know if the distortion level of this equipment is below threshold of human perception, but there are some folks in this forum who blindly believe that equipment is superior the lower its distortion, but that's like saying equipment with a high-frequency range extending to 10MHz is superior, lol.

It's entirely "unscientific" delusion.

 

[MaxBuck]

"High fidelity" to me implies that the equipment reproduces sound with minimal alteration to the signal. What constituted high fidelity in 1947, given the limitations of the available technology of the time, should not be regarded as high fidelity today. Or so it seems to me.

 

[fpitas]

"High fidelity" to me implies that the equipment reproduces sound with minimal alteration to the signal. What constituted high fidelity in 1947, given the limitations of the available technology of the time, should not be regarded as high fidelity today. Or so it seems to me.

Agreed. I think the amp designers of that time would be aghast that modern tube amps purposely introduce distortion.

 

[VQR]

Agreed. I think the amp designers of that time would be aghast that modern tube amps purposely introduce distortion.

They'd also be ecstatic how much clean wattage we can get and flabergasted people purposefully chase low wattage.

 

[fpitas]

people purposefully chase low wattage

Well...they're too cheap to use good transformers, at least.

 

[computer-audiophile]

Well...they're too cheap to use good transformers, at least.

Which particular model are you addressing? Or is it just something you say?

By the way, this thread is about tube preamps.

 

[fpitas]

Which particular model are you addressing? Or is it just something you say?

By the way, this thread is about tube preamps.

I doubt VQR was referring to preamps, so there's that.

 

[computer-audiophile]

I prefer to discuss very specific amplifier models. Only then we can make a judgement whether they are well or poorly designed and whether they fit a particular application or not.

 

[DualTriode]

Hello All,

Among the faithful they speak of an open hand and a closed hand. Among the opinionated I think of those with the closed hand as using it like a fist.

The DUT in this thread is built to a price point with specific technology to meet a specified level of performance that is the engineering or design goal. The question to be answered with the bench test tools is: “is the design goal met”? That is engineering.

So in this case was the design met? Yes!

Is it possible to do better? Yes! That too is engineering.



Thanks DT

I test old school stuff on my bench just for the fun. I might even listen to it for a few months.

I built a SET 12B4A tube headphone amplifier. I did not like the old school hum and buzz in my ears so I upgraded the power supplies with statistical shunt regulated versions. With the help of a Keysight O-scope and APx analyzer on the bench the hum and buzz was gone.

The upgraded power supplies cost as much as the custom output transformers.

See the attached FFT.

https://www.diyaudio.com/community/attachments/mjsr-sch-0-3-png.505439/

 

[computer-audiophile]

So in this case was the design met? Yes!

Is it possible to do better? Yes! That too is engineering.

Good points!

I think you can call this preamp a success in the market. Additional question: When exactly was it introduced? How old is the TdP design in question.
It's not a very high-end device.

Even from this brand there are better and more expensive models.

I upgraded the power supplies with statistical shunt regulated versions

Well done! A 'clean' power supply is a must.

 

[Postlan]

Hello All,

Among the faithful they speak of an open hand and a closed hand. Among the opinionated I think of those with the closed hand as using it like a fist.

The DUT in this thread is built to a price point with specific technology to meet a specified level of performance that is the engineering or design goal. The question to be answered with the bench test tools is: “is the design goal met”? That is engineering.

So in this case was the design met? Yes!

Is it possible to do better? Yes! That too is engineering.



Thanks DT

I test old school stuff on my bench just for the fun. I might even listen to it for a few months.

I built a SET 12B4A tube headphone amplifier. I did not like the old school hum and buzz in my ears so I upgraded the power supplies with statistical shunt regulated versions. With the help of a Keysight O-scope and APx analyzer on the bench the hum and buzz was gone.

The upgraded power supplies cost as much as the custom output transformers.

See the attached FFT.

View attachment 313434

https://www.diyaudio.com/community/attachments/mjsr-sch-0-3-png.505439/

Good job. No NFB?

 

[DualTriode]

Good job. No NFB?

No added feedback, just the local feedback from the Single End Triode cathode resistor.

DT

 

[Digby]

I wonder if the distortion characteristics of X valve amplifier or tube could be analysed, then reproduced through a 'clean' solid state amp, to see if the same effect (good/bad/otherwise) were perceived by the listener. If you could figure out what distortion was present and introduce it to the signal, perhaps you could have a 'clean' solid state amplifier emulate a valve amp, such that the difference between the two was imperceptible? Then chop and change at your leisure without the expense and heat of valves.

 

[SIY]

I wonder if the distortion characteristics of X valve amplifier or tube could be analysed, then reproduced through a 'clean' solid state amp, to see if the same effect (good/bad/otherwise) were perceived by the listener. If you could figure out what distortion was present and introduce it to the signal, perhaps you could have a 'clean' solid state amplifier emulate a valve amp, such that the difference between the two was imperceptible? Then chop and change at your leisure without the expense and heat of valves.

First question is, can the distortion actually be heard? That's an important baseline before chasing emulation.

 

[Digby]

First question is, can the distortion actually be heard? That's an important baseline before chasing emulation.

True, have any double blind tests between valve and solid state amps been conducted? I wonder how open those who believe in valves are to such tests (perhaps you need a selection of people who believe they can hear the difference, and prefer the perceived difference of valves over ss)

 

[SIY]

True, have any double blind tests between valve and solid state amps been conducted?

Many.