Saturday, 28 February 2015

KOGA Audio Pentha: Luscious Pre

After the exhilarating experience with KOGA Aimez , I wanted to hear the capability of a full KOGA amplification. Hence, KOGA Audio have came up with a single input Pre-Amp named Pentha. And I received it in a timely manner..... on the first day of a 4 days long weekend of CNY. Had so much fun over the 4 days weekend with this unit.


The Pentha is a 2 box pre amp; consists of the main unit and PSU. This reference prototype comes with a single RCA input, specifically for CDP/DAC input located at the rear side. The fascia is simple on the main unit, just a volume knob. Minimalist is the designer's philosophy.

It also comes with a pre out to connect to KOGA Aimez or any other power amp.

Its a mini sized pre amp, frill free design with the following specs.

Full Class A amplification using only discrete semiconductors, ie no opamps
Input sensitivity : 150 mV-2V (adjustable)
Input impedance : 47 kOhm
Load impedance : 10 kOhm (min)
Supply Voltage : 24 Vac
Finishing : Anodized Grey or Matte Black


After the session with KOGA Aimez Hybrid Power Amp, I have decided to go for a similar set up of my own system:
  • Musical Fidelity M1 CDT - CD Player
  • SONY MDS JA20ES - MD player
  • Dell laptop - CAS
  • Musical Fidelity M6 DAC
  • KOGA Aimez Hybrid Power Amp
  • Speaker Cable - Siltech Classic Anniversary 330L
  • Interconnects - Siltech AES/EBU digital cable, Siltech RCA 


I played the track Always On My Mind by Willie Nelson from the KOGA Sampler CD (excuse the voice of my kids in the background). I could not believe my ears how big the sound stage is.  The Pentha was definitely designed perfectly to pair with the Aimez.


In order to have a more apple to apple comparison with my previous review of the KOGA Aimez hybrid power amp, I used the same track list for this combo.
  • Time To Blow - Del Paxton (CD)
  • Metallica - Enter Sandman (Hi Res FLAC - 24/96)
  • Era Gia Tutto Previsto - Andrea Bocelli (MP3 256 kbps)
  • Mustika - M. Nasir (MP3 192 kbps)
  • Viopipe - Butterfingers (MP3 320 kbps)
  • Hotel California - Eagles (Hi Res FLAC - 24/192)
  • Bamboleo - Gypsy Kings (MP3 320 kbps)
  • KOGA Sampler - Various test music (CD)


I had the opportunity to 'use and abuse' this combo for a good 4 days over the long CNY weekend. And continued listening to it for another week for about 2 hours a day.

Time To Blow sounded more lean this time. The double bass was still the highlight, but the Pentha just injected another element of tonal balance where all the instrument  blended in even better than when the Aimez power amp was reviewed previously. The sound of the crown on the ride cymbal sounded very crisp and the piano sound was delivered with a little bit of warmth injected to it. Very enjoyable when coupled with the big soundstage the Aimez is delivering

Enter Sandman sounded more controlled and tight compared to the airy experience I had in my previous review. The Pentha just smoothen things up when paired with the KOGA Aimez. The bass sounded fuller and tight but with a bigger soundstage, The shredding guitar of Kirk was highly pitched but it did not sound irritating at all as the Pentha just balance it out with a pinch of low end  envelope. Metallica sounded fierce and authoritative, And I like it.

Era Gia Tutto Previsto was presented in a more uplifting experience where Andrea's vocal sounded more toned and bold with a pinch of low end signature. The Pentha injected a bit more life compared to my  previous review. I particularly like how the deep vocal of Andrea was delivered in a manner as if you can feel that its coming out deep from his vocal cords. Exhilarating. The instrument used on this track was also placed and conveyed in a very layered presentation. I felt like the various instrument coherently blended in with the vocals.

The bass in the track Mustika suddenly appears which balances out the high frequency that was really evident in my previous review.It created a new sound field  where M. Nasir's vocals filled up the room more with real life strength. Big and bold but melodious and full of soul. The angklung sounded very traditional as it should be  and the classical guitar solo had the right amount of reverb to create a lively solo part.

Viopipe however gave me a totally different presentation. I lost the grunge rawness of this track. The violin still had good delivery but the extra bass that came with this track made it sound warm and pop-ish. It was un-grunged.. The drums on this track sounded more full instead of hollow as I believe it was intended to be.Still very enjoyable but I prefer the raw sound of the previous review.

The swooshing sound at the beginning of the Hotel California track was more evident this time around. The guitar works sounded bigger and the upstroke was definitely detail and crisp as per previous review.  However, the overall track sounded livelier and opened up. The high pinch sound from the guitar was less evident most probably balanced out by a cleaner and solid bass delivery. Vocal and drums were the highlight to me. Very emotional delivery for the vocals and clean and timely delivery by the percussion sound.

In Bamboleo is where it truly shined. Even at a lower volume, the different layers of guitar sound can be easily identified. Not only the guitar, even the castanets sounded very clear and crisp.The separation between instrument was very unique where as if the sound was being released one after another.  The vocals sounded very energetic and it had a sense of authority which I didn't experienced this before.


So, what did Pentha do to the Aimez? It basically balances out the high frequency delivery of the Aimez, in a nutshell. Its a neat simplified pre amp for a simple set up with just one source to handle. It matches perfectly with the Aimez.

Who will enjoy this combo? I believe....

  • Someone looking for a small and simple system
  • Someone looking for a high quality sound but with limited budget. I believe this combo will only cost less than RM1,000 ~ USD280
  • Jazz, vocals, metal and complex arrangement music lover

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