OSV HT 50 Amplifier
Review by George Sallit


When Trevor at Guildford Audio asked me whether I would like to review an interesting amplifier from Poland I jumped at the chance. One because I trust Trevor’s judgement and two because I am interested in audio originating from what was called Eastern Europe, now Central Europe.

For me, there seem to be three main blocks of audio products. The more established European/USA/Japanese audio companies who have considerable experience and expertise in audio and have been involved with audio for decades and decades.

The second main area is China and Korea. These countries/areas are making really interesting audio at reasonable prices. They may have initially relied on engineers/designers from the first block to ‘come over’ and use their manufacturing capability, but that has changed and there is top-quality audio coming from China and Korea designed and engineered by Chinese specialists. The only problem is the range of audio quality from China is very wide and you could pay a similar amount for a brilliant amplifier or one that is OK. That is changing but buyers need to be careful.

But an area now capturing the audiophile world's attention is Central Europe. Here we have very high-end equipment such as Thrax (Bulgaria-made) with a lot of 5-figure equipment that sounds amazing as well as more reasonably priced audio. I was taken by the less expensive Thrax Ares and Enyo amplifiers recently: https://www.hifiwigwam.com/forum/threads/thrax-ares-integrated-amplifier.111377/ so, I had no qualms about reviewing the OSV amplifier, in fact, I was looking forward to it.

So, who are OSV amplifiers? Their web page states that OSV Audio began in 2012, when its engineers in Katowice, Poland, started manufacturing amplifiers for the guitar market under the name JK Amplifiers. Over time, the brand became known among musicians as having some of the best-sounding guitar and bass gear. The Bass Player Magazine named the company "Gear Of The Year 2019", beating out some of the world's most established brands. At the same time, JK Amplifiers was producing Hi-Fi amplification, receiving rave reviews from private and retail clients. Today, as OSV Audio, we continue the tradition of offering one of the finest Hi-Fi gear to a diverse and competitive market.


So, they have a 10-year track record and decided to expand into the home market with their first product the OSV HT50 amplifier. The OSV HT50 is a hybrid integrated amplifier with a valve preamplifier and a solid-state power amplifier. The preamplifier uses a JJ 6SL7 with 2 NOS 6J9P-E valves. They are NOS valves and I was assured they have sufficient stocks to continue to support the amplifiers. It uses an SRPP stage, which some claim provides a more transparent sound and others disagree. The power amplifier of the OSV HT50 is a Class AB bipolar amplifier that provides (surprise, surprise) 50w/channel at 8 ohms and 75w/channel at 4 ohms. The amplifier uses Jantzen Audio Superior Z-Cap and the AC line has a DC blocker that reduces transformer hum and mains line noise.


It has 3 RCA inputs and a Bluetooth input (optional extra) with OSV’s output sockets that take bare wire, spades and 6mm plugs.

I can’t add any more as that is all that is available for home audio, plus their excellent track record with guitar amplifiers.

I have to be honest and say I have mixed experiences with hybrid amplifiers, some give the best of both worlds and others, the less-than-good aspects. I put the amplifier into my system and let it play for a reasonable amount of time to ensure all was settled and then started listening.

I played my ‘new test’ list of tracks through my Denafrips T+ DAC and Gaia DDC, Audionote DAC 4.1x and the newer (to me) Mola Mola Tambaqui with Grim MU1. A fairly wide collection of DACs. CDs came through the Jays Audio CDT2 Mk III transport. The OSV HT50 amplifier played into my Avalon PM1s loudspeakers. The cabling was silver ribbon throughout plus Audioquest Diamond AES/EBU. With the Tambaqui I had to use Cardas XLR to RCA converters as the OSV HT50 amplifier only has RCA inputs.

My first test track was from Christy Moore’s This is the Day album; the track So Do I. This track is a very natural recording of guitar and voice. It is also used as a test track of a natural recording by a major USA speaker company. Through the OSV HT50 the sound was very natural and conveyed the slightly raw Celtic nature of the music. This stops the music from being too twee. The guitars were well captured and had good tonal density. A good start and there were no obvious joins between the valve and solid-state sections.

Next was Sounds of Silence, but not the one you are thinking of, the version from Disturbed’s Immortalized album. They are a Chicago Heavy Metal outfit. This is a pared-down piano and vocals track that starts nicely and then takes a more edgy path. David Draiman (lead vocal) builds the tension up and lets rip near the end of the track. The OSV HT60 captured all the anger and sheer grit in his voice that evades a lot of amplifiers. This track hits home through the power of his voice as the music is compressed. And the OSV HT50 captured almost all of that anger and certainly better than nearly every under £10K amplifier I have heard.

In complete contrast, A Little Rice and Beans from TRYPNOTYX by Victor Wooten, Dennis Chambers and Bob Franceschini is a big slab of great musicianship from three excellent jazz players. This is a very good recording with real dynamics and the amplifier captured that well. And more importantly, it relayed the tunes that were being played. Some amplifiers produce a great sound that can be admired but they make a mess of the tune being played and the interactions between the musicians. The OSV HT50 did not turn the music into an audio autopsy and kept the musical elements separate to allow me to hear the individual contributions without losing the coherence of the three musicians playing tightly together.

On to bigger and more powerful music. Hans Zimmer’s 2049 starts with artificial bass thumps played with power and dynamics and set the soundstage size (BIG). The bass openings are followed by natural instruments in strong contrast to what has gone before. The bass intro was not just deep bass notes, the tones changed as the sound decayed and the positions moved back into the distance. The OSV HT50 captured those changes and set the scene for what was to come. A big dynamic fast-moving film. I quickly followed this with his theme from the Batman film with a similar build-up, but in this longer track the theme is allowed to develop more and the OSV HT60 amplifier captured those contrasts. Finally, playing Beethoven’s 9th finale recorded by Reference Recordings, the dynamic contrasts hit home and when played loud captured the drama of the music.

I got the same overall conclusions for the rest of my test tracks. There were no joins between the valves and solid-state as the amplifier has been well crafted to achieve that unified sound.

Is it perfect? No of course not, but I had to bring out the big guns to hear differences and all of them cost far more that the OSV HT50. The amplifier could not match the ultimate dynamics of the other amplifiers, the Luxman 900s and the Audio Research Ref 75SE, or achieve the full tonal density of my SET valve amplifier. But let’s be fair, those amplifiers are acknowledged leaders at their price points, which are far more than the OSV HT60.


So, in conclusion, the OSV HT50 amplifier, is a great hybrid amplifier that brings out the slight warmth of valves and the control of solid-state all in a neat box that proudly displays the valves at its heart. It costs £6,500, making it a great buy and should be on your list of amplifiers. As you will buying it from Guildford Audio you can be sure you will get the right service and a chance to listen to it at home. I need to keep an eye on OSV and others in Poland as we become more familiar with their audio.

Guildford Audio: https://guildfordaudio.co.uk/

OSV Amplifiers: https://osv-audio.com/