The hunt for the perfect 300b amplifier

[essrand]

On my last NYC trip, I went on full throttle, hunting and auditioning all the top 300b amplifiers. This is a tale of 5 such amplifiers from Shindo, Engstrom, Kondo, Luxman and Air Tight. It was a fun trip with lots of learnings. Do take a read of the part one of my adventure:

 

[muralimmreddy]

thanks for one more engrossing post, and for introducing list of world music albums

if i may ask, why did you zero in on 300b to start with?

 

[Hari Iyer]

@essrand
Wondering if any of the 300B amplifiers in your list are SET directly coupled, 2 stages and with AC heating - technically speaking.

 

[essrand]

thanks for one more engrossing post, and for introducing list of world music albums

if i may ask, why did you zero in on 300b to start with?

Thank you.

To answer your question, in two parts:
1. I tried a few tube amps with different tubes, and a 300b SET was the one I liked the most for my taste in music.
2. A 300b is one of the few amps who's SET variant can drive a real world speaker, the other tubes that can do that in SET form are either too heavy (211, 845) or too rare, and I don't buy amps that I cannot lift myself

@essrand
Wondering if any of the 300B amplifiers in your list are SET directly coupled, 2 stages and with AC heating - technically speaking.

3 of them were SET amps, but beyond that I cannot answer as to their implementation, I am neither qualified enough nor particularly interested in implementation, as I am in the end result which is the sound.

I do believe (now) that a good designer is more pertinent than the implementation (PP vs SET), or the tube used, so I just evaluate the end-result -- the sound.

 

[Decadent_Spectre]

Have you also looked at pre amps which use the 300B? What are the good choices available new?

 

[essrand]

Have you also looked at pre amps which use the 300B? What are the good choices available new?

I haven’t.
Although, It does seem quite decadent to use an expensive 300b power tube for preamp purposes, doesn’t it?

Why only 300B or 211 or 845 can drive as you say real world speaker ?

There must be many others ( f2a, gm70, at20 come to mind) that give 8w or more in set configuration. But they are not very mainstream or too heavy (gm70) or too rare as I mentioned.

 

[Decadent_Spectre]

I haven’t.
Although, It does seem quite decadent to use an expensive 300b power tube for preamp purposes, doesn’t it?

I wouldn't know, I don't use tube equipment so I am not really aware of the prices of the tube or the pre amps that use them. I have a passing interest in trying one sometime and whether it is a waste or not is of no consequence to me as long as it does what I want but that is a little ways off. Besides a tube pre is the only way I would be able to use them, I am not aware of any tube amps that produce enough power for my usage.

 

[arj]

My personal experience with the 300B is limited to having heard a few in other systems, but considering its more about the midrange and with a soft rolloff at both ends its not a natural fit. Hence this will need to be compensated for in the design which makes it far more expensive than the 12xxx etc tubes with are easier to work with.

 

[Decadent_Spectre]

My personal experience with the 300B is limited to having heard a few in other systems, but considering its more about the midrange and with a soft rolloff at both ends its not a natural fit. Hence this will need to be compensated for in the design which makes it far more expensive than the 12xxx etc tubes with are easier to work with.

While I am not aware of tubes but if what you say is correct the 300B could be a very nice sounding tube if one is not hung up on objectivity/bandwidth. The distortion in the various domains that tubes add is why I wish to try them, I had tried one but was not happy with it but it did intrigue me enough to keep me interested in tubes as I saw potential, the one I tried simply wasn't my flavor. A while ago I had made a thread about a tube pre amp but other than the first (relatively low cost) try I didn't pursue it. It is on the agenda but I have been busy, maybe next year. I'd like to add of the little I have read on tubes the 300B interests me the most and I would like to give it a try.

 

[essrand]

My personal experience with the 300B is limited to having heard a few in other systems, but considering its more about the midrange and with a soft rolloff at both ends its not a natural fit. Hence this will need to be compensated for in the design which makes it far more expensive than the 12xxx etc tubes with are easier to work with.

In the hands of a good designer, the 300b doesn’t suffer these limitations. Mine certainly has fantastic bass and a good top end while retaining the midrange magic.

None of the 300b amps I auditioned suffered from this stereotypical roll offs.

 

[arj]

In the hands of a good designer, the 300b doesn’t suffer these limitations. Mine certainly has fantastic bass and a good top end while retaining the midrange magic.

None of the 300b amps I auditioned suffered from this stereotypical roll offs.

While I have not heard the amps you have mentioned, I was speaking of this from a preamp perspective and that it needs to be designed well to compensate for the same in the preamp.

On the amp , in the end its the synergy with the speaker than the amp standalone parameters which matter. Am sure the 300B with speakers you have evaluated are a good synergy. 300b's as a SET is perhaps the most organic of tubes if you need more than 5W.

While I am not aware of tubes but if what you say is correct the 300B could be a very nice sounding tube if one is not hung up on objectivity/bandwidth. The distortion in the various domains that tubes add is why I wish to try them, I had tried one but was not happy with it but it did intrigue me enough to keep me interested in tubes as I saw potential, the one I tried simply wasn't my flavor. A while ago I had made a thread about a tube pre amp but other than the first (relatively low cost) try I didn't pursue it. It is on the agenda but I have been busy, maybe next year. I'd like to add of the little I have read on tubes the 300B interests me the most and I would like to give it a try.

Since you do use High power SS amps, i would suggest a traditional 12AX7 perhaps followed by the 12AU7 tube which are all a classic design and perhaps the most popular since several decades. Expert designers here can comment more on any of the Pros and Cons,

 

[kratu]

Interesting. These amplifiers are some of the acclaimed ones. I look forward to reading your impressions of the other three amplifiers. I understand this is not a near A/B test, considering the variables of different speakers and components used in each setup.

I see this is from 2019 and you finally decided to go with Shindo. (Going by your previous threads)

My search for the ultimate tube amplifier in NYC and India

So, I have been on a long journey to find the perfect stereo tube amplifier. I thought I would start penning down down my past year's search for my "final" tube amplifier, one amp to rule them all perhaps for entertainment value for other FMs or perhaps it might help someone else who is going...

www.hifivision.com

John DeVore showcased few of his amplifiers in a video and AirTight 300B makes it to the list. (It was more of trade-in between the brands). So, it gets some points, considering the designer of O/96 speakers has them.

Speaking of high-end amplifiers, one other Japanese brand is the elusive Wavac (represented in India by Audire). I'd also be open to other tubes and see how they work. Another brand in that spectrum is NAT Audio GM70.

 

[Hari Iyer]

3 of them were SET amps, but beyond that I cannot answer as to their implementation, I am neither qualified enough nor particularly interested in implementation, as I am in the end result which is the sound.

I do believe (now) that a good designer is more pertinent than the implementation (PP vs SET), or the tube used, so I just evaluate the end-result -- the sound.

Yes @essrand it's all about implementation hence the question is being asked. There maybe 1000s of 300B amplifier designs and you probably cannot be going around listening to all of them even if you have the time and money. You will narrow down based only on the implementation of the amplifier.

For me it's power supply design, SET / PP, 2 Stage or 3 stage design, direct coupled or capacitor coupled or transformer coupled, AC heater or DC heater.

I have been using 300B amplifier since 2014, SET, 8+8 Watts until 2020. Again now I am usingvthem to drive my h-frame subwoofers. My personal opinion about 300Bs with CLC power supply, 3 stage design and DC heater is - it's very sterile and dry sounding with this kind of implementation. YMMV.

 

[Hari Iyer]

Since you do use High power SS amps, i would suggest a traditional 12AX7 perhaps followed by the 12AU7 tube which are all a classic design and perhaps the most popular since several decades. Expert designers here can comment more on any of the Pros and Cons,

Both the 12au7 and 12ax7 cannot drive a 300B as it's a low mu tube. It will need tobe a 3 stage design for doing that. All magic lost when you add another stage to drive a final tube. Better to use a 2 stage design with a 6aq4 or 12bz7 tube in a 2 stage with 300B to get adequate jump factor.

Even if the 12ax7 is a high mu tube, it's plate current not enough to drive a 300B final tube in 2 stage design. 12ax7 typically not used inca 3 stage design.

 

[arj]

Both the 12au7 and 12ax7 cannot drive a 300B as it's a low mu tube. It will need tobe a 3 stage design for doing that. All magic lost when you add another stage to drive a final tube. Better to use a 2 stage design with a 6aq7 or 12bz7 tube in a 2 stage with 300B to get adequate jump factor.

This was for a preamp but not to drive the 300B amp rather a SS amp.

BTW whats your view on a 300B based preamp ?

 

[Hari Iyer]

This was for a preamp but not to drive the 300B amp rather a SS amp.

BTW whats your view on a 300B based preamp ?

I have never designed a tube based preamp. My setup doesn't need one. All my source - digital and analogue are audio transformer coupled and have enough gain that don't require any preamplification.

 

[Decadent_Spectre]

While I have not heard the amps you have mentioned, I was speaking of this from a preamp perspective and that it needs to be designed well to compensate for the same in the preamp.

On the amp , in the end its the synergy with the speaker than the amp standalone parameters which matter. Am sure the 300B with speakers you have evaluated are a good synergy. 300b's as a SET is perhaps the most organic of tubes if you need more than 5W.


Since you do use High power SS amps, i would suggest a traditional 12AX7 perhaps followed by the 12AU7 tube which are all a classic design and perhaps the most popular since several decades. Expert designers here can comment more on any of the Pros and Cons,

Perhaps that is conventional wisdom for the tube folk but I have always done things my way, and it has worked. It's also more of a "try", not a "must use".

 

[essrand]

Interesting. These amplifiers are some of the acclaimed ones. I look forward to reading your impressions of the other three amplifiers. I understand this is not a near A/B test, considering the variables of different speakers and components used in each setup.

Yes, totally not a A/B test. Just some experience and data points.

I see this is from 2019 and you finally decided to go with Shindo. (Going by your previous threads)

My search for the ultimate tube amplifier in NYC and India

So, I have been on a long journey to find the perfect stereo tube amplifier. I thought I would start penning down down my past year's search for my "final" tube amplifier, one amp to rule them all perhaps for entertainment value for other FMs or perhaps it might help someone else who is going...

www.hifivision.com

There’s a twist in the tale, I did not go with Shindo at all.

John DeVore showcased few of his amplifiers in a video and AirTight 300B makes it to the list. (It was more of trade-in between the brands). So, it gets some points, considering the designer of O/96 speakers has them.

This amp is the one that got away

Speaking of high-end amplifiers, one other Japanese brand is the elusive Wavac (represented in India by Audire). I'd also be open to other tubes and see how they work. Another brand in that spectrum is NAT Audio GM70.

I have heard wavac in a show, also the big nat magmas in a show and the smaller gm70 at a dealer in Chennai, neither impressed me much. That being said of course it was show conditions, and a long time ago.

I would someday like to try a Shindo GM70. It’s probably the only amp that will get me to change my current components.

 

[essrand]

Just published part two of this 300b hunt and about a surprise winner of 300b "hunt".

The hunt for the perfect 300b amplifier (in NYC) - part 2

Air Tight, Kondo, Luxman and a surprise winner

audiofool.substack.com

 

[arj]

If you take the Idiot dealer out of the equation , how was the Air Tight in terms of involvement with the music relative to the others ?