SET amp owners thread

[jeff1225]

Sun Audio 2A3 set is a very enjoyable high gain SET using Tamradio transformers.

 

[wbass]

Sun Audio 2A3 set is a very enjoyable high gain SET using Tamradio transformers.

Thanks for the reminder on those. Any idea how to go about getting a 230V version? Unfortunately, I'm not in the position to build a kit. I suppose I could get one off ebay from Japan and just run a step-down transformer....

 

[jeff1225]

Thanks for the reminder on those. Any idea how to go about getting a 230V version? Unfortunately, I'm not in the position to build a kit. I suppose I could get one off ebay from Japan and just run a step-down transformer....

You can email Sun Audio Japan directly. They are very responsive.

 

[bonzo75]

The Sun Audio 2a3 punches way above its price but will not drive Tannoys

 

[jeff1225]

The Sun Audio 2a3 punches way above its price but will not drive Tannoys

It would have no problem driving Tannoy reds and blacks. Modern Tannoys need not apply.

 

[morricab]

View attachment 156420

cute little amp, details?

 

[bonzo75]

Sun audio VT25 compared with destination audio and Thomas Mayer

Post in thread 'SET amp owners thread'
https://www.whatsbestforum.com/threads/set-amp-owners-thread.27070/post-675575

 

[DasguteOhr]

A interstage transformer driven by dc current from the first tube stage( best low impedance). It needs a air gap when it not done good you have a lot of distorsion and poor dynamics.
Cap couping can have the same problem. The size of the grid leak resisitor and the coupling capacitor determine the dynamics and the pulse processing( tube rolling can go really bad at this position).
plague or cholera, choose what you like.ok direct coupling loftin white is a option too.

Interstage Coupling

 

[DasguteOhr]

View attachment 156420

Nice sun audio uchida, congrats

 

[iaxel]

This just got in…

 

[bonzo75]

This just got in…

View attachment 156729

What is it driving

 

[iaxel]

What is it driving

Some 99dB horns. To be revealed in a few months time. Playing with amplifiers combinations atm.

Now playing (beautifully!)

 

[bonzo75]

Some 99dB horns.

Did you ever obsess on why it never got to 100

 

[iaxel]

Did you ever obsess on why it never got to 100

All the time
My least favorite grade back in high school.

 

[jeff1225]

Did you ever obsess on why it never got to 100

Mine are 104

 

[Atmasphere]

You could add Berning and Shindo.

The Berning neatly sidesteps the bass reproduction issue most SETs suffer by the use of its air core output transformer.

Another surprise, the old Garber absolutely slayed an Audio Research Ref75 (non-SE) that I'd expected to like quite a bit. The Ref75 only had about 10 minutes to warm up though.

Hardly any tube product can be taken seriously without at least a 1/2 hour to hour warmup!

Thanks for the replies. Anyone ever get ears on the Garber/Fi amps? As above, I was pretty impressed with the 2A3 / 45 amp, particularly when running with the 45's, but I don't have enough experience with SETs to know if what I heard is typical or can be bettered. I'm aware that much depends on the amp layout and parts, and even similarly spec'd amps can sound different, so maybe just after general guidance.

I heard the Fi 2A3 amps at the Philadelphia Triode Show back in the late 1990s. IMO it was one of the better sounding amps at that show (its been far too long to remember how they sounded; I'm simply passing along my impressions). The speakers were only 98dB though so the amps simply could not be played all that loud.

Nearly all IT coupled designs I have heard excel in drive.

Since distortion often causes amplifiers to sound louder than they are, the increased distortion caused by hysteresis in the various coupling transformers adding to distortion is a very simple explanation of why this might appear so.

A better way to drive any DHT is by direct-coupling to its grid. But because that will be inherently lower distortion, such an amp would sound like it has as much 'drive' (whatever that means) even though the circuit is more capable of driving the tube beyond saturation.

 

[wbass]

The Berning neatly sidesteps the bass reproduction issue most SETs suffer by the use of its air core output transformer.

Hardly any tube product can be taken seriously without at least a 1/2 hour to hour warmup!

I heard the Fi 2A3 amps at the Philadelphia Triode Show back in the late 1990s. IMO it was one of the better sounding amps at that show (its been far too long to remember how they sounded; I'm simply passing along my impressions). The speakers were only 98dB though so the amps simply could not be played all that loud.

Since distortion often causes amplifiers to sound louder than they are, the increased distortion caused by hysteresis in the various coupling transformers adding to distortion is a very simple explanation of why this might appear so.

A better way to drive any DHT is by direct-coupling to its grid. But because that will be inherently lower distortion, such an amp would sound like it has as much 'drive' (whatever that means) even though the circuit is more capable of driving the tube beyond saturation.

Yes, we were doing our best on limited time, and even after only 2 hours, I was having serious listening fatigue. In an ideal world, we'd have let that ARC amp warm up a bunch more and come to it fresher, as well. I'll have to give it another try some other time.

I'll investigate the Berning.

 

[escultor]

I own a Fi 2a3 super X, it sounds good especially with a flat plate 2a3 or the Vaic mesh 2a3, the construction is noticeably different from other amps, I don't like the 2a3 that much but this one sounds OK

 

[adamaley]

I own a Fi 2a3 super X, it sounds good especially with a flat plate 2a3 or the Vaic mesh 2a3, the construction is noticeably different from other amps, I don't like the 2a3 that much but this one sounds OKView attachment 156982View attachment 156984

I've always admired the aesthetics of this amp from afar. Thanks for sharing. What are you driving with it?

 

[escultor]

I've always admired the aesthetics of this amp from afar. Thanks for sharing. What are you driving with it?

With Shindo WE RA1474 my favorite preamp