SET amp owners thread

Atmasphere · Feb 9, 2024

AudioHR said:
Still open to 300b recommendations.

Try as many as you can. That is the only way you'll find one that works the best with your amp.

By applying feedback properly, you could reduce a lot of those differences, without taking away the smooth character of the amp (you would also get lower noise and greater transparency). I outlined the method in this post.

DasguteOhr · Feb 9, 2024

It's best to install a small ELMA switch where, for example, you can use 6 different resistor + cap combinations for dose of feedback. Then you are more flexible with different speakers. Then you can tune to the perfect sound possible.

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Atmasphere · Feb 9, 2024

DasguteOhr said:
It's best to install a small ELMA switch where, for example, you can use 6 different resistor + cap combinations for dose of feedback. Then you are more flexible with different speakers. Then you can tune to the perfect sound possible.

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Just remember to mix the feedback with the incoming signal rather than using the cathode of the input tube!

DasguteOhr · Feb 9, 2024

Atmasphere said:
Just remember to mix the feedback with the incoming signal rather than using the cathode of the input tube!

It depends on how many gain stages the amplifier has. a good article about it.

Understanding Audio

AudioHR · Feb 9, 2024

Atmasphere said:
Try as many as you can. That is the only way you'll find one that works the best with your amp.

By applying feedback properly, you could reduce a lot of those differences, without taking away the smooth character of the amp (you would also get lower noise and greater transparency). I outlined the method in this post.

Thanks I appreciate the advice. I have tried a fair number of tubes over the years. Many I could live with but always looking for that next level up. An issue with the supposedly better 300b tubes is their cost , at least for me. So identifying possible contenders via reviews and recommendations is a smart thing to do I think.

Hmm... I will investigate your ideas on feedback. The Cortese is dead quiet as is but unless you try something it shouldn't be dismissed. Essentially the point of your post!

Atmasphere · Feb 9, 2024

DasguteOhr said:
It depends on how many gain stages the amplifier has. a good article about it.

Understanding Audio

It starts out well, but goes off the rails at the point entitled 'Feedback Circuits'. At that point the feedback is depicted without a series input resistor, and so you can't know how its being mixed. As the article goes on, we see feedback being applied thru a coupling transformer or cathode of a tube, both of which distort the feedback signal.

Put another way, the feedback node must be linear, and should not be non-linear as we see in the case of a transformer, tube or transistor. Otherwise expect trouble.

IMO/IME you have to be really careful about this else you cause the problems for which feedback has been denigrated, especially in the SET world!

jeff1225 · Feb 9, 2024

AudioHR said:
Interesting you would inquire about this.

I have with my Zen Triode, replacing the stock 5U4G rectifier with a Mullard CV593. I had been informed that upgrading the rectifier could have a very positive effect. Maybe even more so than changing the power tubes? The stock tubed Zen Triode sounds way better than it should for anywhere near its cost.. The Mullard rectifier was a definite upgrade so I was extremely pleased.

Actually I do have a few new valves Including a rectifier ordered for the Shindo Cortese.

Thank you for the tip. Where did you get the Mullard?

AudioHR · Feb 9, 2024

jeff1225 said:
Thank you for the tip. Where did you get the Mullard?

I purchased the Zen Triode second hand. The seller included the Mullard as well as the stock rectifier. You never know wth some of these tubes as they were often rebranded by different distributors but it seems to be a legit Mullard. So I can't tell you where you might purchase it.

If I were purchasing vintage tubes I would put my trust in Andy at Vintage Tube Services.

bonzo75 · Feb 10, 2024

This was commissioned by a Swiss businessman to Ming Su, a designer at Goto a joint collaboration with Great Plains audio and an Englishman named John Sheerin. The Swiss then traded it in many years later for the Vox Olympian. Kevin installed it at Jim‘s place.

3 Goto drivers do the top half, and GPA Altecs take over on midbass.

Now, with the Kronos Pro with an AN IO Gold feeding a Slagle silver SUT, into an audio note Japan M7 built in phono and pre, biamped with an art audio 300b (Takatsuki) with Border Patrol PSU power supplies, and the midbass unit gain matched with a Class D amp, this is one of the finest systems I have heard.

lots of alignment work that went in here.

Maine Coon tweeter

bonzo75 · Feb 10, 2024

bonzo75 · Feb 10, 2024

This system was quite over the place for a while. Jim managed to tone it with the 300b biamped by carefully finding a matching class D for the woofer that had a volume control to match the gain. I tried only the 300b across and it muddied the whole spectrum.

the system jumped up a few levels after I requested him to put in his audio note Japan M7 phono plus pre, and used that to replace the Aurasound Preda preamp with a custom phono.

AudioHR · Feb 10, 2024

Love this thread! I especially enjoy seeing all of the great systems out there. Time to post mine, I thought I had but having just reviewed all of the posts I realized I hadn't.

My speakers are Coherent Audio Neo 18 designed and custom built by Frank Fazzalari in Ontario, Canada. They are a dual concentric design with Radian low mass woofer and compression driver. There is also a super tweeter. A ported design Frank has done some interesting structural work in the interior of the cabinet. These speakers are efficient and easy to drive aided by a well thought out crossover with quality parts and speakers with a fairly smooth impedance curve.

I have two amplifiers available. My primary amp is a Shindo Cortese 300b, a recent edition Model. In the summer I mix in the Decware Zen triode. My preamplifier is a Shindo Monbrison. The Shindo components are unlike most of what I have heard before, let's just say I am a fan.

The sources are a BrinkMann Bardo/Hana Umami for vinyl and an Antipodes S Series/Ayre 20 DAC for streaming.

I was really impressed with the listening spaces that our members have posted including some of the views. I have a dedicated room which just happens to feature a large picture window. Probably not the best thing sonically but it is nice to look outside, lol.

bonzo75 · Feb 10, 2024

in reality it has great highs with sweetness and highly emotional

bonzo75 · Feb 10, 2024

Beethoven

bonzo75 · Feb 10, 2024

Bruckner 7

AudioHR · Feb 10, 2024

bonzo75 said:
View attachment 125105

Nice turntable!

bonzo75 · Feb 11, 2024

LL21 · Feb 11, 2024

bonzo75 said:
Beethoven

Of the more recent systems you've been video'ing...do you have a particular favorite set of speakers? I found the earlier one you compared with Yamamura quite interesting. Although we dont have vinyl, we do have the FIM Winson MA CD remastering of Bruch Scottish Fantasia Oistrakh and recorded it on iphone just for fun.

Never going to be the same as actually being there...so curious as to your favorite of these various speakers you've been hearing. Presume its still the really tall, white 4-speaker with the FLH horns that nearly touch the ceiling?

Rensselaer · Feb 11, 2024

bonzo75 said:
This system was quite over the place for a while. Jim managed to tone it with the 300b biamped by carefully finding a matching class D for the woofer that had a volume control to match the gain. I tried only the 300b across and it muddied the whole spectrum.

the system jumped up a few levels after I requested him to put in his audio note Japan M7 phono plus pre, and used that to replace the Aurasound Preda preamp with a custom phono.

The last time I heard Jim’s system he was driving the speakers with, I believe, a Threshold solid state amplifier. Yesterday, when I arrived, he was driving the mids and top end with a 300B SET, the bass with a tiny class D amplifier and a self-powered sub-woofer. The sound put out by Jim’s system was considerably better than when last auditioned.

We shut off the sub-woofer and I could discern no difference in the sound (Kedar’s selection of classical).

Then the passive crossovers were bridged and the class D amplifier removed so that bass and treble would be controlled by the 300B SET amplifier alone. It sounded good but not as good as when the speakers were bi-amped, so class D amplifier reinserted.

Then Jim brought out a modified Kondo Audio Note pre-amplifier and power step up transformer to try. At first, no doubt due to built up grime/corrosion on the contacts after sitting out of use for years, it made no sound. But after Jim turned the switch back and forth a couple of times contacts worked and we were treated with decent music. That was done using his usual phono stage through the AN pre. The sound was as good, if not better, than his two-box preamplifier.

Next, we used the AN phono stage in the AN pre-amp and the whole sound experience took a significant step up in quality. Not that you can easily discern it from Kedar’s phone recordings but in person definitely. Kedar has heard a great many systems in his lifetime and I know of no one else with that degree of experience so I asked him, hearing Jim’s system as it was playing then, how does it compare with the very best out there. If I remember correctly, Kedar said “ it’s right up there”. My thoughts exactly.

Footnote: before we wired in the modified AN preamplifier, Jim said he bought it for £7,000 (some years ago) but has seen the same selling for £17,000 - £18,000. I asked him if he wanted to sell it and he said nothing, till after we auditioned his system and I said it sounded really good. He then asked me with a smile if I still wanted to buy it and I replied “I could no longer afford it”.

christensenleif@msn.com · Feb 11, 2024

I have a quartet of unobtainum ALE Permendur Beryllium drivers for sale.......
7550DEBe and 1750DEBe
PM if interested

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