Tubes Asylum: REVIEW: EAR/Yoshino 509 Manufacturer: by chris.redmond2@bushinternet.com

Model:	509
Category:	Manufacturer:
Suggested Retail Price:	$NA
Description:	100 wpc Monobloc valve amps
Manufacturer URL:	EAR/Yoshino
Manufacturer URL:	EAR/Yoshino

Review by chris.redmond2@bushinternet.com ( A ) on February 23, 2002 at 04:32:23
IP Address: 212.159.144.201

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for the 509

At this very moment I`m listening to Pink Floyd`s `Meddle` on Musical Fidelity Sound Lab`s UDCD518, and can`t imagine any system on the planet doing it more justice since the EAR 509`s were installed.
Guitar is rich, colourful and organic, bass kicks in and rattles the remaining ornaments I haven`t yet blu-tacked down, and the whole effect is one of `live`.
It was Pink Floyd`s use of virtually this same design to produce their best work, and the fact that Water Lily cut their own award winning albums from lathes of a similar pedigree (not to mention MFSL`s use of EAR equipment) that led me to enquire about the 509`s on `Tubes` in fact.
Heathen that I am, the 100 watts per channel of power from valves played a more than passing attraction, as did the modest price for a used pair I had my eye on.
To attempt to describe the character of the 509`s would just result in me giving a description of what the source, pre, speakers and cables are doing together as I believe the 509`s are so transparent as to be near invisible; therein could be the `problem` when considering this amp.
As I was myself informed on this forum, the 509`s are not SETs so don`t expect the slightly rose-tinted presentation (which I freely admit to prefering on vocals) and seductive qualities inherent in the SETs I`ve personally heard unless the actual recording has these qualities.
However, with good AAD CD`s (MFSL or Mastersound even better) or recordings from specialist audiophile labels, vocals are almost as lifelike as I`ve ever heard and far better than 99% of systems, which is going some as my speakers aren`t really mid-range champions by any means; in fact I`d love to hear the 509`s with a decent vinyl front-end - I gather a lucky few even have Quad electrostatics with 509`s inbuilt to great effect.
So soundwise the 509`s are my idea of the ideal amp for all seasons, and Steve Robinson - an avid DIYer with his own website - who`s had his for many years thinks they reward any upgrades to the rest of the system without revealing their own limitations.
To conclude I`ll take the easy option and repeat some of the technical aspects from the sheet provided with my second-hand 509`s.
"...circuit comprise of 5 tubes, of which 3 are small pin twin triodes and the other 2 are high Power capability television horizontal scan pentodes, type PL509 (I use Mullard PL519s) selected for it`s reliability and linearity.........
...There are 3 basic voltages supplied. A centre tapped bridge circuit to provide 520 volts for the plates and 260 volts for the screens, together with a half wave supply of 120 volts negative for biasing the output tubes and the tail current of the first tube.
The output transformer is used passively in a `Balanced Bridge` mode to provide low distortion and wide frequency response coupled with minimal phase shift. It is used to convert a relatively high voltage low current output down to a low voltage high current output suitable for driving conventional practical loudspeakers. Since it is fed from a low impedence source, it introduces negligable amounts of distortion, it`s performance is equivalent to the output choke used in `solid-state` amps of around 4uH.
Finally, stability of the whole amplifier is assured at low frequencies by direct coupling the first 3 stages so only the last stage between the voltage driver and the output is coupled by a capacitor. At high frequencies only the minimum of compesation is employed. Open loop response is flat over the audio band."
Output transformer is a special in-house 13 section Bifilar wound bobbin on grain oriented core.
Power output = 100 watts
Frequency Response = 3Hz - 30KHz + 0 - 1dB, 2Hz - 80KHz + 0 - 1dB
Power Bandwidth = 12Hz - 60KHz - 3dB at less than 0.5% THD
I.M.D. = less than 0.2% at any level from 10m Watts equivalent power
Signal to noise Ratio = 94 dB down from 100 watts
Input impedence = 25Kohm
Weight = 17Kg
Size = 30cm (W) x 23cm (D) x 16.5cm (H)

Product Weakness: Hard to find anyone willing to sell a pair of the originals.
Product Strengths: Valves with bass! Supremely musical, neutral without being sterile - valves are easy to source and relatively inexpensive.

Associated Equipment for this Review:
Amplifier:	EAR 509 monoblocs
Preamplifier (or None if Integrated):	Audio Note M2
Sources (CDP/Turntable):	Wadia WT3200 transport with Audio Note DAC4.1x.
Speakers:	15" Tannoy Monitor Gold drivers in DIY cabinets with replacement crossovers designed by Russ Andrews.
Cables/Interconnects:	Stealth Fineline Mk11 silver digital IC, Kimber Select KS-1020 IC. No speaker cables needed as amps are almost integral with speakers.
Music Used (Genre/Selections):	Everything imaginable.
Room Size (LxWxH):	15` x 15` x 9`
Room Comments/Treatments:	Massive speakers for such a relatively small room, but dual concentric design minimises rooms effect somewhat. Besides, the old adage "It`s surprising how many problems attributed to the room acoustics dissappear when better equipment is purchased".
Time Period/Length of Audition:	3 months
Other (Power Conditioner etc.):	PS Audio P600 power regenerator, separate spur made from Kimber High Current mains cable, as are all power cords.
Type of Audition/Review:	Product Owner
Your System (if other than home audition):	As above.

Product Weakness:	Hard to find anyone willing to sell a pair of the originals.
Product Strengths:	Valves with bass! Supremely musical, neutral without being sterile - valves are easy to source and relatively inexpensive.