Yarland FV-34C III Tube Amplifier 230V version

Most components are mounted to a circuit board. Working inside this amp is fairly difficult, as it is quite cramped and not easy to remove the circuit board, so amateur upgraders be warned.

The Yarland FV-34C III uses 2 x Sovtek 6BQ5 / EL84’s per channel in push-pull, triode mode. The Yarland amp is cathode-biased meaning that you can change output valves without having to open it up and set the bias. The drivers are 6N3 / 5670 configured as paraphase circuits (high gain phase splitters). The balance of the phase splitters is manual, via two pots inside the amp, so beware when tube rolling or you will end up with uneven gain on each channel. The heaters for left and right channels are run off separate transformer windings. The right channel has a pair of 300 ohm resistors from the heater supply to ground for hum balancing. Funnily enough the left channel simply has one side of the heater supply grounded because it is also used as the power supply for the input selection relays. The hum balancing resistors are on the board but not connected.

I inserted the Yarland FV-34CIII into the system (Pioneer DV-575A and Mission M-70’s), let it run for a few hours, and then sat down to listen. Pleasant surprise. The result was listenable, enjoyable and without harshness. There is a lack of very low bass, but the warmth makes up for this. It is possible to listen to the music rather than the system. I found I could make for lack of deep bass by placing the speakers closer to the wall. The amp also reproduces harmonics better than it should. I think it beats any similarly priced solid state amp in terms of musicality.

I tried “rolling” the driver valves with a pair of NOS Phillips JAN 2C51 (similar but not identical to 6N3). Very “dark” and “glassy” sounding; the Chinese 6N3’s provided produce more detail and realism.

The power output of this Yarland FV-34CIII is exaggerated somewhat depending how you read the specs. EL84’s in triode mode PP delivers 5 or 6 watts RMS per channel. You will need speakers exceeding 90dB per watt to get decent dynamic range.

The Yarland FV-34C III is not silent. There is some mains hum evident from the speakers and when I put my ear up to the speakers there are some slight ticking noises coming from the left channel and some valve noise from the right. This is not really evident from the listening position. The valve noise is easily cured by replacing the noisy driver valve, but the ticking is not (I’m still trying to figure out what is causing it; I have sweated all the solder joints in the unit, but now think it is a noisy resistor or capacitor). However, the level of hum is better than some “good” subwoofers produce at idle.

I have made the following modifications to the unit: (1) rewired the AUX input as a line level output for a future subwoofer (2) removed the power supply components for the input selection relays and by-passed the relays altogether. This change actually improved the sound considerably! (3) disconnected the ground from the left channel heater supply and connected the hum balancing resistors.

I still intend relocating the power switch to the rear of the amp, as the original location puts mains right close to the left channel circuitry and probably contributes to hum. Also, the grounding scheme is just adequate, but I would like to ground the heater supplies separately to the central ground point via their hum balancing resistors as this is good practice and should lower the noise floor.

I hope you find this interesting. This amp provides a small window into high end audio for a really good price and it’s strengths outweight it’s faults. It can make a budget CD player pleasant to listen to. I would like to try it with a pair of KEF Cresta 10’s (90dB/W) and a decent small subwoofer such as the Tannoy TS-8.

Review courtesy of audioasylum.com