SET amp owners thread

[AudioHR]

I believe that the circuit has to be considered with the evaluation of tubes. For example, the best tube I have in my three stage 300b amps are the standard EM Labs. The Elrog was boring and slightly vailed.

True.

I have a Shindo Cortese 300b that I would like to find some replacement tubes for. The rectifier is a 5U4GB, the drivers are 6BM8. The Takatsuki 300b and WE 300b have been recommended by a Shindo dealer. Having had a bad experience with the new and expensive WE 300b tubes in another amp I am not keen to go down that road again. I have not heard the Takatsuki but they are expensive and it would seem that they are not a preferred tube on this forum.

In my previous amp I tried a number of the less expensive tubes both Chinese and Eastern European. They all performed well and each had its own character. The Black Treasures were smooth and rich with a somewhat less defined bass. The Eastern European tubes like the EH and Gold Lions tended to have a little more definition overall and a slightly more forward character. The Gold Lion's I remember as having a nice tight and dynamic bass.

I am using the JJ in the Shindo now, actually they sound quite good. Maybe it's more the Shindo than the JJ? Any way I would like to have a replacement set of 300b on hand. I could live with a less expensive replacement but wouldn't mind seeing how the Cortese performs with one of the better tubes. What ever that is, lol! Any advice from Shindo users? I know Shindo is not a thing on this forum but there must be some of you out there, lol!

 

[AudioHR]

After level-balancing my multichannel system, probably a 2-channel CD by Rosanne Cash named 'The List'; I LOVE the first song named 'Miss The Mississippi And You'. It's very much mono-miced and overdubbed, but her voice reveals much to me.. Then probably a 2-channel SACD named 'Tutti' issued by Reference Recordings--full-range, very dynamic orchestra.. My next three in no particular order but always heard early are extremely natural-sounding MC SACDs--Tchaik. Sym.5 (4th mvmnt.) with Dimitri Kitayenko and the Gurzenach Orch. Koln on OEHMS OC 667; Elgar Sym. 1 and Organ Sonata (orchestrated) with Richard Hickox and the BBC NO of Wales on CHANDOS CHSA 5049 (slow movements of each, tracks 3 and 7); and Grieg Dvorak Elgar string suites, with Conrad VanAlphen and the Rotterdam Chamber O, TELARC SACD-60623, where I listen to the Elgar Serenade for Strings, o. 20.. These three tracks excel in transparency...the feeling that I'm in the hall with the orchestra, sitting on a stepladder behind the conductor, and that these 30-or-so musicians are playing for ME.. When the sun and the moon and my brain and heart are all aligned, only I and THE MUSIC exist...it's...magic.

I am a huge Rosanne Cash fan. Having heard her at the intimate Weber Auditorium in Calgary I would say you have to listen to "Ten Song Demo" to fully appreciate how good she can sound. It's an early recording and she has lots of incredible songs since then but just listen.... you will hear the magic!

 

[AudioHR]

This is my first post here. ..

This is my private setup. It's consisting of Coherent Loudspeakers Neo 15, SW1X DAC II SPX and Triode Labs 45 Mini SET. I'm playing ripped FLAC and WAV files from my own collection. I'm using Jriver as media player.

View attachment 97655

View attachment 97656

Zulu I appreciate your post. A great looking system and with the Coherent 15 speakers I am thinking it sounds wonderful too!

 

[AudioHR]

View attachment 103492

field coil Lowther with Shindo 300b, Thomas Mayer 45/2a3, custom PX4.

View attachment 103493

Mayer 10y + D3a Vs Shindo Monbrison, PTP lenco with audionote field coil

Some great equipment here!

 

[AudioHR]

No videos but generally the speaker needed the higher power and drive of the Shindo 300b. If we had something more powerful that would have worked too. The Mayer phono pre combo was quite better. The lowther's are an overall a long listen, fit into big living room, musical sound. There were some Voight corner horns from the 30s that had potential but were not set up for demos. Also a long mono horn with Lowther

So what was your assessment here? Some lovely combinations available I would expect. A little more detail please.

 

[AudioHR]

NEWS FROM THE KR AUDIO VA350 PURITY

In november 2022 my VA350 once in some days, went into protection. Waiting 30 seconds, it was working again for lots of hours.
I measured the bias again. It was a liitle low, but my biaspot was almost on its end. I was suspecting the T100 tubes would be done.
I somehow got the email adress of the designer of the KR audio amps, Marek Gencev. I wrote him an email at sunday evening, which he answered on monday morning at 7.30h (!):
The bias for VA350 is 1.10Vdc. If the amplifier goes into a protection even with correct biasing you should check thermal stability of TL431
(-30Vdc), which I did:

View attachment 103703
The TL431 is in the blue circle.
The -30Vdc can be measured at the Tantal cap, the yellow blob left to the TL431.

View attachment 103707

You can see the measure-probe on the left side of the Tantal cap. The blue arrow markes the TL431. As I heated the TL431 with a hairdryer, it was clearly visible that the voltage got from 29Vdc (cold), to 26Vdc (warm).

So, I ordered the TL431 and all the caps on the main PCB, as one of the 450V caps looked strange (see first pic, left to the TL431)
These are 4x 47uF/ 450V (RM7,5mm , H31,5mm, Ø16mm)
6x 47uF/200V (RM5mm, H20mm, Ø12,5mm)
2x 10000uF/16V (RM7,5mm, H40mm, Ø18mm)
All together some €15....

After I'd changed all, the bias was good again. I adjusted it and checked for several days if the bias was drifting. All was as should be.
When I got to do the listening, I was very surprised at how much better the VA350 now sounds!! More dynamics and the soundstage opened wide now with lots of layering and soundstagedepth... Very very nice!! A friend of mine who was here just before and direct after the modification said it has transformed my system. I was still thinking, it would be my room-acoustics and my speakers, not being able to layer well, but here it is
So, when someone has a KR Audio amp (the main pcb is almost the same in all amps. The TL431 is in all of them) he should check the bias and look for the drifting TL431.

Also, I had one T100 tube, which was making ticking noises sometimes (once in a few weeks) Sounded like playing a record, even when not playing anything. I asked Marek, what it could be. His answer:
"With a noisy tube, try to play the amplifier at maximal volume with disconnected speakers for few seconds.
Likely there is an impurity on mica holders or a grid and you can clean it with a transient signal."

This is really scary, as the amp itself makes all the musik-noise
This I had to do twice within a week and is now gone.

So, as I can say, I'm very happy to have it solved and that my system is sounding so incredible now!!

Disclaimer: don't do this yourself if you are not familiar with electronics! LETHAL VOLTAGES INSIDE!!!
but it is really easy to do

Thx for the mail support from Marek, who helped me a lot and answered my many questions!

Regards, Remco

p.s. One surprise when I turned over the main PCB:
View attachment 103706
Nice silver mica caps over the already very good Mundorf Mcap Supreme Silver/ Gold!

A non starter for me! Could you have received some warranty assistance on this?

 

[jeff1225]

True.

I have a Shindo Cortese 300b that I would like to find some replacement tubes for. The rectifier is a 5U4GB, the drivers are 6BM8. The Takatsuki 300b and WE 300b have been recommended by a Shindo dealer. Having had a bad experience with the new and expensive WE 300b tubes in another amp I am not keen to go down that road again. I have not heard the Takatsuki but they are expensive and it would seem that they are not a preferred tube on this forum.

In my previous amp I tried a number of the less expensive tubes both Chinese and Eastern European. They all performed well and each had its own character. The Black Treasures were smooth and rich with a somewhat less defined bass. The Eastern European tubes like the EH and Gold Lions tended to have a little more definition overall and a slightly more forward character. The Gold Lion's I remember as having a nice tight and dynamic bass.

I am using the JJ in the Shindo now, actually they sound quite good. Maybe it's more the Shindo than the JJ? Any way I would like to have a replacement set of 300b on hand. I could live with a less expensive replacement but wouldn't mind seeing how the Cortese performs with one of the better tubes. What ever that is, lol! Any advice from Shindo users? I know Shindo is not a thing on this forum but there must be some of you out there, lol!

Shindo might not be a thing here, but the set discussing is limited to this sub. I love Shindo gear and think it sounds fantastic.

I have also enjoyed the PsVane black bottle 300B’s. They sounded great and can be had relatively inexpensively.

 

[AudioHR]

Pnoe AER BD3b compare with Decware zen triode 2.5w, coincident Frankenstein mk2 8w, and border patrol with two power supplies 6w. Latter two are 300b. The border patrol with Sophia princess was less than the coincident with Genalex, but once the Genalex was moved over the border patrol was much better.

unfortunately demo was on digital. Will go back in a few months when he sets up analog

View attachment 123391

Pnoe AER BD3b compare with Decware zen triode 2.5w, coincident Frankenstein mk2 8w, and border patrol with two power supplies 6w. Latter two are 300b. The border patrol with Sophia princess was less than the coincident with Genalex, but once the Genalex was moved over the border patrol was much better.

unfortunately demo was on digital. Will go back in a few months when he sets up analog

View attachment 123391

Interested to hear how the Decware performs with these speakers. I have the basic Zen Triode and it continues to amaze me. Likely speaker and system dependent but I have no problem saying that paired with my Coherent Audio Neo 18 speakers it is stunning. Well worth waiting for in the Anniversary mode I would say.

 

[AudioHR]

Just finished rereading this amazing thread, it took a few days!

Bonzo you must take some credit in creating this and of course your very self assured and sometimes provocative comments keep it going. I envy the fact that you have listen to so many systems.

There was a lot to learn and think about and I loved seeing and hearing about all of the great SET's/speaker systems, your passion for this hobby was obvious! There are some fabulous looking components and systems out there and I would love to hear each and every one of them.

Sorry I didn't listen to any of the videos. Maybe I will figure that out down the road? Call me skeptical.

Of course there was quite a bit of "robust debate" too. I found most of it quite informative but I do hope that someday those most involved will get together at each others places to listen to some music and have a few beverages of theirs choice.

I also realized I had not posted my system, I will, I thought I had.

Thank you every one for being part of the most interesting thread on the What's Best Forum! Keep the conversation going!

 

[bonzo75]

I believe that the circuit has to be considered with the evaluation of tubes. For example, the best tube I have in my three stage 300b amps are the standard EM Labs. The Elrog was boring and slightly vailed.

Sometimes. The TM 300b is tungsten thoriated, the ER 300B - MO was molybdenum, compared to other 300bs, so that would play a role. And then there is the older ER.

 

[bonzo75]

Just finished rereading this amazing thread, it took a few days!

Bonzo you must take some credit in creating this and of course your very self assured and sometimes provocative comments keep it going. I envy the fact that you have listen to so many systems.

There was a lot to learn and think about and I loved seeing and hearing about all of the great SET's/speaker systems, your passion for this hobby was obvious! There are some fabulous looking components and systems out there and I would love to hear each and every one of them.

Sorry I didn't listen to any of the videos. Maybe I will figure that out down the road? Call me skeptical.

Tbanks - videos were the best part - one of the regular video followers one bought the JBL 4550 after listening to the dual FLH videos - I have been recording videos since 2019, and the top systems I have heard show up in my videos. Are there a couple of misleading ones (good systems that don't sound as good or not so good systems that sound excellent) - yes. Doesn't change anything.

 

[morricab]

True.

I have a Shindo Cortese 300b that I would like to find some replacement tubes for. The rectifier is a 5U4GB, the drivers are 6BM8. The Takatsuki 300b and WE 300b have been recommended by a Shindo dealer. Having had a bad experience with the new and expensive WE 300b tubes in another amp I am not keen to go down that road again. I have not heard the Takatsuki but they are expensive and it would seem that they are not a preferred tube on this forum.

In my previous amp I tried a number of the less expensive tubes both Chinese and Eastern European. They all performed well and each had its own character. The Black Treasures were smooth and rich with a somewhat less defined bass. The Eastern European tubes like the EH and Gold Lions tended to have a little more definition overall and a slightly more forward character. The Gold Lion's I remember as having a nice tight and dynamic bass.

I am using the JJ in the Shindo now, actually they sound quite good. Maybe it's more the Shindo than the JJ? Any way I would like to have a replacement set of 300b on hand. I could live with a less expensive replacement but wouldn't mind seeing how the Cortese performs with one of the better tubes. What ever that is, lol! Any advice from Shindo users? I know Shindo is not a thing on this forum but there must be some of you out there, lol!

Have you played with rectifiers?

 

[bonzo75]

True.

I have a Shindo Cortese 300b that I would like to find some replacement tubes for. The rectifier is a 5U4GB, the drivers are 6BM8. The Takatsuki 300b and WE 300b have been recommended by a Shindo dealer. Having had a bad experience with the new and expensive WE 300b tubes in another amp I am not keen to go down that road again. I have not heard the Takatsuki but they are expensive and it would seem that they are not a preferred tube on this forum.

In my previous amp I tried a number of the less expensive tubes both Chinese and Eastern European. They all performed well and each had its own character. The Black Treasures were smooth and rich with a somewhat less defined bass. The Eastern European tubes like the EH and Gold Lions tended to have a little more definition overall and a slightly more forward character. The Gold Lion's I remember as having a nice tight and dynamic bass.

I am using the JJ in the Shindo now, actually they sound quite good. Maybe it's more the Shindo than the JJ? Any way I would like to have a replacement set of 300b on hand. I could live with a less expensive replacement but wouldn't mind seeing how the Cortese performs with one of the better tubes. What ever that is, lol! Any advice from Shindo users? I know Shindo is not a thing on this forum but there must be some of you out there, lol!

I wouldn't say the Tak are not preferred. They are by many. They have very good reliability feedback. In terms of sonic, i believe they make the sound dense and bump up the mids, but there are those who prefer this sonically. Depends how much transparency you want to your recordings. For tubes best is to buy and sell used there is a liquid market for them.

 

[bonzo75]

Interested to hear how the Decware performs with these speakers. I have the basic Zen Triode and it continues to amaze me. Likely speaker and system dependent but I have no problem saying that paired with my Coherent Audio Neo 18 speakers it is stunning. Well worth waiting for in the Anniversary mode I would say.

The Border Patrol there sounded much better than the others. That said the Pnoe has to be set up properly and this one wasn't. It is the fussiest of all speakers I have heard - by far - probably due to the lack of crossover. It sounds bad till it sounds awesome. Which is why I would like go back there and repeat the amp compares when he at least gets his analog going. Maybe the Decware will sound good if he got in the Red Sparrow on a linear tracker.

The only other non crossover speaker I liked was the Yamamura and there too Pietro found Shindo 300b and Kondo not suitable, only the Yamamura amps had to be used. So I assume it was difficult too.

 

[morricab]

Have you played with rectifiers?

The reason I ask is that I have found that 5U4GBs are not really that great as rectifiers. In my Silvercore amp, the 5U4GBs I have (Sylvania black plate NOS) are a bit gray tonally and midrange is a bit recessed...not terribly until you compare. They have great bass and transparency overall though. My 1956 Marconi (Italy) 5U4G is just as transparent, a bit less powerful in the bass but OMG it makes the tone and midrange presence SO much better. Little details become more obvious and yet the whole hangs together even better.

I was originally not that keen on the Marconi as it was very midrange centric; however, it has evolved with some hours to open up in the highs and a bit more meat in the bass. I also have a 1955 Marconi that sounds even more midrange centric and closed in on top but it has very few hours on it and I am thinking now it could be the ultimate star if it opens up like the 1956.

Not sure if your amp is able to take 5AR4s or not, but that is a completely different flavor with amazing transparency but a leaner tonal balance.

 

[remdeck]

A non starter for me! Could you have received some warranty assistance on this?

@AudioHR ,

I don't understand your question.
This is not something you can do when you never repaired a tube-amp yourself.
But if you know how to handle a soldering iron safely, you can do this.
Only thing is check if some high voltages are still there before starting.

Otherwise, every repairshop can do this for you. I wrote in detail, if there are any questions, let me know.

The amp works perfectly since then and I listened to my system a lot in the past year.

Regards, Remco

 

[Atmasphere]

I believe that the circuit has to be considered with the evaluation of tubes. For example, the best tube I have in my three stage 300b amps are the standard EM Labs. The Elrog was boring and slightly vailed.

The way the tube interacts with the output transformer is different from tube to tube and transformer to transformer! The load the transformer presents to the tube is different from transformer to transformer and also varies depending on the loudspeaker, since transformers transform impedance. So if you have a 4 Ohm load on the 8 Ohm tap the load on the tube will be cut in half and it certainly won't sound right. So imagine smaller changes depending on the particular speaker involved and you see how difficult it can be to judge a certain tube across all platforms.

Add to that the differences in transconductance from tube to tube of the same brand and matters become quite complicated.

Finally, depending on the driver to the power tube, the distortion can be quite different! If you AC couple you get one distortion, transformer couple another, and direct couple yet another. How that distortion interacts with that of the output section can be quite interesting!

So comments like these are really only valid in the context of a particular amp in a particular system.

 

[AudioHR]

Have you played with rectifiers?

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.

 

[AudioHR]

@AudioHR ,

I don't understand your question.
This is not something you can do when you never repaired a tube-amp yourself.
But if you know how to handle a soldering iron safely, you can do this.
Only thing is check if some high voltages are still there before starting.

Otherwise, every repairshop can do this for you. I wrote in detail, if there are any questions, let me know.

The amp works perfectly since then and I listened to my system a lot in the past year.

Regards, Remco

As far as the question perhaps I misunderstood and your amp was a DIY.

Well I use to be pretty handy with a soldering iron on those Dynaco kits but that was ages ago. I do understand that for those that have the knowledge and skill that doing it yourself is definitely an option, maybe even preferable. At this point in my life I am more comfortable with someone else doing it.

 

[AudioHR]

The reason I ask is that I have found that 5U4GBs are not really that great as rectifiers. In my Silvercore amp, the 5U4GBs I have (Sylvania black plate NOS) are a bit gray tonally and midrange is a bit recessed...not terribly until you compare. They have great bass and transparency overall though. My 1956 Marconi (Italy) 5U4G is just as transparent, a bit less powerful in the bass but OMG it makes the tone and midrange presence SO much better. Little details become more obvious and yet the whole hangs together even better.

I was originally not that keen on the Marconi as it was very midrange centric; however, it has evolved with some hours to open up in the highs and a bit more meat in the bass. I also have a 1955 Marconi that sounds even more midrange centric and closed in on top but it has very few hours on it and I am thinking now it could be the ultimate star if it opens up like the 1956.

Not sure if your amp is able to take 5AR4s or not, but that is a completely different flavor with amazing transparency but a leaner tonal balance.

Hey I really appreciate your input. Yes the Cortese can accommodate a 5U4G.

Earlier today my valve order arrived. Soon I will be listening to an early 1940's National Union 5U4G! It was recommended by Matt Rotunda at Perfect Pitch. Looking forward to hearing it! I also ordered some 1960 Mullard 6BM8 driver tubes, I will listen to these eventually after I come to terms with the sound of the new rectifier.

Still open to 300b recommendations.