Many a man has said - "don't mess with Shindo kit"

[S1chen]

Originally Posted by Plink

Jerome, before concluding 90db speakers with low impedance dips is no big deal, I think you need to do gain a better understanding of low watt SET amps. Try reading the Atkinson measurements section of Stereophile reviews of amps such as the Audio Note Jinro or the Wavelength 300B. I don't believe there is a class A no feedback SET that doesn't *increase* distortion into low impedances. Just isn't possible with valves.

And examine the specs of the 300B tube....sure you can listen to it's full rated power at 8w or so and enjoy listening to the high distortion if it doesn't bother you. But to simplify this down to the size of the power transformer is basically ignoring all of the measurements that are integral to valve amp design.

Stereophile defines clipping as over 1% distortion which will easily be surpassed trying to drive 2 ohms with a 300B set. And then imagine trying to play loud peaks at 2 ohms. You're already going to be at high distortion with just a couple watts at 93db with such an amp and those Wilson speakers. I imagine this is some of the reason you can read posts here by Mr. Halpern advising that Shindo amps work best with sensitive, high impedance speakers (Devores, old Altecs, etc...).

SET actually start at 5% distortion even in very low watt of 1 Watt, this is due or the lack of feedback. So no matter you use a 100dB or 90dB speaker, distortion start right with SET. But music is subjective and no one really able to understand the actual reproduction in a home system. Hence all speaker, all amp, all Pre sound different and it will impress one from another.

What I want to say here is measurement is use as a tool to guide buyer to ensure they pay the right price for the right product. However, measurement is also lead many to go into getting the wrong product as one read too much. SET measure the worst, follow by push pull tube and last is solid state amp. But most of the beautiful music is still reproduced out from SET, and hence people are buying tube amp. Even in this forum of Shindo, some experience that their little 10 watt tube sound better than their 30w or more solid state.. And you know what, distortion can also turn out to be useful since no one can afford a perfect digital transport, DAC, turntable, cartridge...etc. adding some even harmonic distortion make some music come alive as if they sound in live performance.

Finally, I would recommend any one with their beloved low power watt power amp to try them with their dream speaker before any the purchase. You may get surprises many a time.

[Jerome W]

Very interesting post once again.

This explains probably why JC Verdier was confident to let me his SET 845's monoblocks on my PMC speakers.

[Plink]

S1chen, some SETs have much less than 5% distortion at one watt at a benign impedance (see the reviews I mentioned). I agree with this post and that is why I said if listening to that distortion works for you, then no problem. We all know that it is possible with valve amps as they clip gracefully.

I just wanted to mention what actually happens when these class A amps try to drive low impedances regardless of the size of the power transformer.

I had one 300B SET I owned scoped and found it did really well (around 5% distortion at it's maximum output 8 watts). It did fairly well with my 99db/1 meter sensitive speakers. However, a 2 watt 45 amp did not do so well (this scenario is similar to using a 8 watt 300B amp on 90db speakers leaving impedance differences out of the equation). During this time, I also had Naim equipment (class B) in house and it was very easy to understand the differences. Over the years I have learned to understand what this distortion sounds like (at least in my own system) and I do not like it. Hence, why I use class A push pull. For those not bothered by this distortion, then by all means, have a go.

A friend of mine once said on set vs push pull...with SET, my heart says "yes" but my brain says "no". I think that is a good way to put it. He owns Wilson speakers, btw.

[S1chen]

Originally Posted by Plink

S1chen, some SETs have much less than 5% distortion at one watt at a benign impedance (see the reviews I mentioned). I agree with this post and that is why I said if listening to that distortion works for you, then no problem. We all know that it is possible with valve amps as they clip gracefully.

I just wanted to mention what actually happens when these class A amps try to drive low impedances regardless of the size of the power transformer.

I had one 300B SET I owned scoped and found it did really well (around 5% distortion at it's maximum output 8 watts). It did fairly well with my 99db/1 meter sensitive speakers. However, a 2 watt 45 amp did not do so well (this scenario is similar to using a 8 watt 300B amp on 90db speakers leaving impedance differences out of the equation). During this time, I also had Naim equipment (class B) in house and it was very easy to understand the differences. Over the years I have learned to understand what this distortion sounds like (at least in my own system) and I do not like it. Hence, why I use class A push pull. For those not bothered by this distortion, then by all means, have a go.

A friend of mine once said on set vs push pull...with SET, my heart says "yes" but my brain says "no". I think that is a good way to put it. He owns Wilson speakers, btw.

Not all the 300B amp are build alike. As a DIY and designer of my own 300B amp, (3 stage amplification: 6SN7 in differential long tail to match the shindo bal output into a 6V6 with interstage for the 300B, 300VA main transformer, Tamura output tran, 1800uF with 3 choke), I have also experience many 300B amp off the shelve which totally cannot make it. When I mean cannot make it is the amp completely cannot drive the big speaker with 90dB and the bass is missing in action. Of course, if the amp is driven to clip while it demand for more loudness, the sound is un-pleasant.

Another point i find is the wilson cannot use the 8 ohm tap on those tube amp as it will sound harsh...

As I mention, I play in a decent small area where I only need 90-93 dB (I measure the sound level) which enough to fill the room, and this level will awaken my wife to come in to turn the volume down. Beside, I have the cary 805AE before, try the audio note silver signature conquest, all have more than 20 watts and can play way louder. But when I play them in my normal listening level, these good amp just cannot touch the magic of the simple 300B SET.

In the past, I have Plinius 100, Goldmund minesis 28, Burmester 911, tube push pull, cary 805AE, before my 300B. while the solid stage get better and better with more power, it just dont have the magic of the tubes. On a very reviewing speaker like the Alexia, I am happy with my 300B amp.

Hence, I stress that bring your favourite amp to test the dream speaker before any purchase. Anything can be possible, it can turn out to be surprises but it can be a total disaster too.

BTW, I think we are off track as we are getting away from the Shindo discussion. So let take it off line if we like to discuss this further.

[Alberto]

Originally Posted by Plink

A friend of mine once said on set vs push pull...with SET, my heart says "yes" but my brain says "no". I think that is a good way to put it. He owns Wilson speakers, btw.

My heart says SET and for my brain to agree I need to also have my heart say yes to compatible speakers. Shindo 10+10W SET + Tannoy = Great, nothing missing or wanting. But I am quite sure it would not do as well with all speakers.

Bottom line, more than any other components (with the possible exception of cartridge and phono stage) one has to think of amp & speakers as a combination.

Alberto

[Plink]

Agreed Alberto. Indeed, my friend said this in the context of using a SET with his Wilsons. It certainly wasn't a statement against all SETs all the time.

[Alberto]

Originally Posted by Plink

Agreed Alberto. Indeed, my friend said this in the context of using a SET with his Wilsons. It certainly wasn't a statement against all SETs all the time.

Hi Plink, I agree. I was not implying that your friend was implying otherwise. Just strengthening and repeating the concept that the the idea that amp and speakers have to be considered as a "pair" for best results is particularly true with SETs.

Alberto

[leicachamp]

I have to agree with S1Chen. All components including Shindo are built to a price point. A manufacture must include parts/tubes that are readily sourced and also at a price that the manufacturer can make a profit.

We all agree that if Shindo included the Auditorium Hommage transformer in their preamps then the price of the preamps would be a lot more expensive.

The same reasoning should apply to Shindo's stock valves. I am sure the valves in their preamps are very good, but the best possible? I dont think so. Shindo uses what they can get in quantity and at reasonable prices.

I have a current Masseto for the last 7 months and am totally in love with it. Tube rolling was not in my mind even though i have plenty of great NOS tubes at my disposal.
But since reading the post by S1Chen i thought i try and roll the Jan12at7 with my GEC2900. In Short "WOW", the sound have bigger tone and soundstage. I am not very good at describing sound, but it definately was a great improvement and not just different. Next i am going to try rolling the 12au7 with some gold label mullards.

But i do understand that in many instances tube rolling will just change the sound or if using inferior tubes , the sound could would worse.

[KenSea]

I have tryed a lot of different tubes in my Shindo preamp and what I have noticed is every tube has a different favor and in the end it depends on your system as to which you will perfer. What Shindo uses for his speakers are in most cases very different than the average Shindo owner has, so in the end its matching things to your system. What i have really learned is the rare NOS tubes is a pricey addiction.
But in the end its all fun and Shindo preamps are great to listen to with any tubes in it. The other thing sooner or late everyone will roll the tubes as they all drop in performance as the hours add up.

[gortnipper]

I have recently done a bit of tube rolling through the VR, and ended up with a configuration that quite surprised me in the end.

In my system, the tube that made the most difference (but, not too much of a surprise for me) in rolling out was the 6x4. I got a noticeably increased tonal depth and blackness in replacing the stock JAN Philips with some NOS GEC CV4005.

The stock Tesla EF184 were keepers, when compared to NOS Mullard or Tele tubes. Not a lot in it, but noticeably truer is how I would put it.

The stock Jan Philips ECG 12AT7WA were a huge surprise. My experiences with JAN Philips ECG have always been a disappointment. In the first stage of the phono, these tubes were quite a bit better than my Telefunken ECC801S, which sounded bright and sterile in comparison. Other standard 12AT7/ECC81 variants did not fare as well either. Wow.

But, I didnt keep the JAN Philips 6189 in the second stage of the phono. I ended up going with my favorite 12AU7/ECC82 variant tube - a CBS/Hytron 5814A. I found that this tube also was killer in the follower position of the phono stage in my old Cary SLP-98P.

All in all, with these two small tube changes, I find the VR now has a presentation that is slightly clearer and deeper yet.