Unison Research Smart 845 Mono's (advice)

[macvisual]

Just wondering if there's any hi-fi folk here own (or have owned) a pair of Unison Research Smart 845 Class A 24watt monoblocks?  They seem to sell between £2750-£2995 on the used market.

I'd love to hear about these please. I know they're not made anymore and would appreciate any thoughts/views/knowledge/ownership on how they sound? - cheers!

I'm using a Promitheus Audio TVC Passive pre-amp, along with Audioplan Kontrast MkII speakers.

Thank you - Peter

 

[MF 1000]

I think Rick ..Bandit Pilot had a pair at one time afaik.  As far as amps with 845 valves be prepared for lots of heat, but a well tuned 845 SET amp delivers a glourious midrange.  Valves last a long time as their original use was in medium wave radio transmitters so were designed to me run at full load etc.

Ive had my MingDa 845 monos for 8 years now (used to drive the midrange in my complex active setup) and doubt I'll ever part with them ....and if I did Awkwardbydesign would snatch them back in an instant.  Before I went active the 845's happily ran my twin B139 driver bass speakers and a pair of Fostex driver full range back loaded horns, so you shouldn't be concerned about lower efficiency speakers either .....845 watts seem to be bigger imho.

 

[Dave Brown]

Very rarely see them back here so appear reliable, even though they do a good impression of a 3 bar electric fire. 

 

[macvisual]

So might the MingDa 845's be cheaper to buy compared to the Unison Research Smart 845's I wonder? I'm guessing the MingDa 845's can be tweaked a little to sound better..? Do the MingDa's come up often for sale?

Sorry for all the questions... Cheers!

Peter

 

[Juancho]

Hi, Ming Da 845s can certainly be tweaked to improve the SQ. Don't forget the Ming Da 3008 amps with 805 output  valves. Once tweaked these sound among the best. There's also the Mastersound 845 amps, beautifully made and very reliable. I have the 845 monoblocs

David

 

[rabski]

People rarely sell 845s once they're sorted and running well. That tells you all you need to know. Papa Laz, ex of this parish, has a Mastersound that was tweaked a little by Coco and IIRC he's had it for longer than I've been a member here. I've had mine for years.

805s are an alternative, as are 211s. Fundamentally, large directly-heated triodes have a lot in common in terms of how they sound, though the implementation in terms of the circuit is quite different. I've heard the URs, but then I've heard various 845s and they are all quite close sonically. There have been a few rubbish ones, but they don't seem to last long because people improve them or use them for parts.

They are ridiculously inefficient and they throw out ludicrous amounts of heat. The latter can be an issue in terms of siting them. Mine usually kills two adjacement houseplants a year thanks to the heat output.

Frankly, if I'd never heard one or lived with one, I wouldn't have given one a second glance based on the specifications. But it would take something more than serious for me to think of parting with mine. Even if I went deaf, I'd still enjoy looking at the glow.

 

[Lurch]

Have to agree on the adictiveness of the 845 sound. Picked up my IA MB845SEs 2 1/2 years ago stupidly cheap, with the intention of a quick listen and then sell on for a very very good profit. They're still here and going nowhere, would have to spend stupid money to better them. 

 

[triumph]

Not heard those monos from UN  but best mate runs  Unison Research Absolute 845 & would not part with it

 

[newlash09]

Not heard those monos from UN  but best mate runs  Unison Research Absolute 845 & would not part with it

Wow...those look just gorgeous. Absolutely smitten

 

[macvisual]

These look huge....!

 

[rabski]

These look huge....!

They are. Not, however, as huge as the dent in your bank account would be. They're a 'statement' product and no matter how good, really not worth ten times what you'd pay for a Smart.

 

[George 47]

Stunning looks and better value than a pair of SS amps in big boxes.

 

[Fourlegs]

People rarely sell 845s once they're sorted and running well. That tells you all you need to know. Papa Laz, ex of this parish, has a Mastersound that was tweaked a little by Coco and IIRC he's had it for longer than I've been a member here. I've had mine for years.

805s are an alternative, as are 211s. Fundamentally, large directly-heated triodes have a lot in common in terms of how they sound, though the implementation in terms of the circuit is quite different. I've heard the URs, but then I've heard various 845s and they are all quite close sonically. There have been a few rubbish ones, but they don't seem to last long because people improve them or use them for parts.

They are ridiculously inefficient and they throw out ludicrous amounts of heat. The latter can be an issue in terms of siting them. Mine usually kills two adjacement houseplants a year thanks to the heat output.

Frankly, if I'd never heard one or lived with one, I wouldn't have given one a second glance based on the specifications. But it would take something more than serious for me to think of parting with mine. Even if I went deaf, I'd still enjoy looking at the glow.

Having owned and loved my icon audio mb845mk2 monos I would sort of have to agree with you except that I found that the Pass Labs amps did everything in the top and mids but also had the bass that the 845 amps found a challenge when everything got loud (despite the simply enormous output transformers in the icon audio mk2 monos). However I did make sure that icon audio had no intention of stopping making their 845 amps before I agreed to sell mine. 
 

My electricity bill did go down by quite a bit though. 

 

[Jules_S]

Those Absolute 845s should be in the "Gorgeous Gadget Porn" thread.   I'm not one for valves nowadays (can't afford the electric bill) but they are stunning. My friend ran a UR S8 and that was a fantastic bit of kit so I can only imagine what these sound like (and how much space they need!)

 

[steve 57]

I had the simply 845 in the 90s it beat a vintage pye Mozart I had restored and moded . About a year after I built my 1st px4 amp and then moved from yammy ns1000s to Lowthers, I had the simply 845 for about 18 months. It was good sounding but a long way off what's possible in my view. But since then I've  heard those 90s 845 valves where not brilliant. 

They do look the part.. But I hated having 1000 volts in my lounge. 

 

[macvisual]

I actually think these Smart 845's are way too big to house in a standard hifi rack. I've spotted a more sensible size Unison Research Triode 25 integrated amplifier.

25 watts Triode mode

45 watts Pentode mode

Anyone owned one of these me wonders ?

Peter

 

[triumph]

Not heard those monos from UN  but best mate runs  Unison Research Absolute 845 & would not part with it

he just changed to the new reference UN pre + monos driving Klipsch La scala

 

[hearhere]

Just wondering if there's any hi-fi folk here own (or have owned) a pair of Unison Research Smart 845 Class A 24watt monoblocks?  They seem to sell between £2750-£2995 on the used market.

I'd love to hear about these please. I know they're not made anymore and would appreciate any thoughts/views/knowledge/ownership on how they sound? - cheers!

I'm using a Promitheus Audio TVC Passive pre-amp, along with Audioplan Kontrast MkII speakers.

Thank you - Peter

I think you are talking about this amp from Unison Research.  I first saw them at a Show decades ago and thought how beautiful they looked and sounded.  Then about 18 years ago I found a used pair for sale at a dealer who offered to lend me them to use with my Avantgarde Uno speakers.  They sounded great, but just too big for my rack so I returned them.  The 856 is a great output valve and (unlike others' experiences) I don't thibk it gets too hot.  I had an Art Audio Carissa 845 stereo amp for a year or so, but also Consonance Cyber 845 monos for the last 15 or so.  I still have these if you are interested in buying them!