Unison Research Triode 25 Integrated Valve Amplifier (with DAC)

andreweast

Wammer
Wammer
Sep 17, 2009
1,954
138
108
London (SE)
HiFi Trade?
  1. No
I'm selling my favourite valve integrated. The Triode 25 is a 45W push/pull amplifier using 4 x EL34 power valves. I've tried several valve integrated amps and this one gave me the best combination of dynamic liveliness and tonal richness. It is especially good with Tannoys. Selling for SOLD (The last s/h unit on eBay sold for £1750)

Condition is fantastic. I hesitate to drop the M word (Mint), but it's in a beautiful state. Comes with a posh looking wooden remote control, valve cage, and original box. The input stage uses 2 x ECC83s and 1 x ECC82. All valves are the excellent modern Tung-Sol.

Although it does have a very good box, I would much prefer pick-up in SE London, or meet up somewhere nearby. I'd prefer the buyer to collect so I can demonstrate it in good working condition.

It also comes with a very good built in USB DAC, and some useful options to allow you to tailor the sound.

The Triode/Pentode switch gives you the option of a more dynamic neutral presentation (Pentode) or a more rich and saturated tone (Triode). I've tried amps with such switches that didn't really impress me (e.g. the Primaluna Dialogue Premium and Eastern Electric M520), but the switch on the Triode 25 is genuinely useful. It also has a choice of Negative Feedback options, so you can further tailor the sound.

I generally used it in Pentode and the higher NFB setting, but there were times when I found Triode/low NFB a revelation. The great thing about this kind of flexibility is that not only can you tailor the sound to your choice of music and speakers, but also to how your ears are feeling today.

Another important thing to note is that rather than having 4 and 8 Ohm taps, the Triode 25 is set at 6 Ohm. For me, this was a real benefit, as I've always found the 4/8 choice annoying and wished I could find the option in-between. I suspect the 6 Ohm setting may be one reason why it works so well with the Tannoys I've been using in recent years.

https://unisonresearch.com/en/prodotti/triode-25-2/

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Last edited:

andreweast

Wammer
Wammer
Sep 17, 2009
1,954
138
108
London (SE)
HiFi Trade?
  1. No
Feeling a bit solid state today: all this enharmonic distortion in my head.

Time for a walk to get my valves glowing.
 
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andreweast

Wammer
Wammer
Sep 17, 2009
1,954
138
108
London (SE)
HiFi Trade?
  1. No
'The heart has four heart valves – the aortic, mitral, pulmonary and tricuspid valves. All four valves open and close to help move blood from one area to another. Two of the valves, the mitral and the tricuspid valves, move blood from the upper chambers of the heart (the atria) to the lower chambers of the heart (the ventricles). The other two valves, the aortic and pulmonary valves, move blood to the lungs and the rest of the body through the ventricles. When the heart valves open and close, they create sounds we know as our heartbeat.'
 

andreweast

Wammer
Wammer
Sep 17, 2009
1,954
138
108
London (SE)
HiFi Trade?
  1. No
This is well below the average selling price and it's an immaculate example. If collection is an issue, I will occasionally be drive North to Leeds, so stopping on the way may be possible.
 
Last edited:
L

Leftfield

Guest
Final reduction to £1350.

This is well below the average selling price and it's an immaculate example. If collection is an issue, I will occasionally be drive North to Leeds, so stopping on the way may be possible.
Beautiful looking amp . I had a an S6 on demo a good few years ago and it sounded really good with a really sweet sounding treble . Good luck with the sale .
 

andreweast

Wammer
Wammer
Sep 17, 2009
1,954
138
108
London (SE)
HiFi Trade?
  1. No
Thanks, it's delightful in looks and sound, and also reliable.

I've had various enquiries on eBay saying they would have bought it if I posted, and that's at a higher price. So I guess that's the stumbling block. I'm thinking about it.
 
L

Leftfield

Guest
I'm selling my favourite valve integrated. The Triode 25 is a 45W push/pull amplifier using 4 x EL34 power valves. I've tried several valve integrated amps and this one gave me the best combination of dynamic liveliness and tonal richness. It is especially good with Tannoys. Selling for £1395. (The last s/h unit on eBay sold for £1750)

Condition is fantastic. I hesitate to drop the M word (Mint), but it's in a beautiful state. Comes with a posh looking wooden remote control, valve cage, and original box. The input stage uses 2 x ECC83s and 1 x ECC82. All valves are the excellent modern Tung-Sol.

Although it does have a very good box, I would much prefer pick-up in SE London, or meet up somewhere nearby. I'd prefer the buyer to collect so I can demonstrate it in good working condition.

It also comes with a very good built in USB DAC, and some useful options to allow you to tailor the sound.

The Triode/Pentode switch gives you the option of a more dynamic neutral presentation (Pentode) or a more rich and saturated tone (Triode). I've tried amps with such switches that didn't really impress me (e.g. the Primaluna Dialogue Premium and Eastern Electric M520), but the switch on the Triode 25 is genuinely useful. It also has a choice of Negative Feedback options, so you can further tailor the sound.

I generally used it in Pentode and the higher NFB setting, but there were times when I found Triode/low NFB a revelation. The great thing about this kind of flexibility is that not only can you tailor the sound to your choice of music and speakers, but also to how your ears are feeling today.

Another important thing to note is that rather than having 4 and 8 Ohm taps, the Triode 25 is set at 6 Ohm. For me, this was a real benefit, as I've always found the 4/8 choice annoying and wished I could find the option in-between. I suspect the 6 Ohm setting may be one reason why it works so well with the Tannoys I've been using in recent years.

https://unisonresearch.com/en/prodotti/triode-25-2/

UNADJUSTEDNONRAW_thumb_4af8.jpg

UNADJUSTEDNONRAW_thumb_4af7.jpg
UNADJUSTEDNONRAW_thumb_4afd.jpg

IMG_3555.jpeg

IMG_3545.jpeg IMG_3551.jpeg
Thanks, it's delightful in looks and sound, and also reliable.

I've had various enquiries on eBay saying they would have bought it if I posted, and that's at a higher price. So I guess that's the stumbling block. I'm thinking about it.
Me again! Interesting what you are saying about the 6 ohm output suiting tannoys which have a 6 ohm impedance. It makes sense .
FYI ( or anyone else’s) Harbeth HL7 compacts are also 6 ohm impedance.( I own a pair ) GLWS .
 
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