The AudioRoom beauty parlour: JVC VN-300 amplifier restoration

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Amplifiers from the 70’s are not only (usually) well built and sound good, they also look good. Or at least as good as an electrical device that has to be functional and durable first can. Silver panels of brushed aluminum, shiny metal knobs, sometimes even backlit power meters – all this has its charm. Some modern amplifiers also have all that, but those that do cost a lot more (and those that don’t cost a lot more, too). And in the case of equipment from the 70’s, you can get a good, aesthetic amplifier at the price of a chain store plastic boombox.

But what if the amplifier that you bought looks like it survived a war? All is not lost. Remember that these units were usually very well built and with a little luck and effort it will be possible to restore not only the amp’s functionality, but also aesthetic appearance.

 

 

The JVC VN-300 that ended up on our operating table clearly had a story or two to tell. The amplifier powered on, but the sound not so much disappeared as it occasionally appeared when working pot and switches. There was a layer of dust inside, but nothing disastrous, we had seen much worse cases. But on the outside the amplifier looked like it had been pulled out of the garbage bin, where it spent the last 2-3 decades growing a dirt coat and losing some limbs (4 knobs were missing).

 

 

We left the cosmetics for later to avoid wasting time in vain. There is no point working on the appearance of an amp until you know that works. So we cleaned the interior and treated the potentiometers and switches with a cleaning agent; we also cleaned the sockets. The first cleaning significantly improved the situation, and after the second cleaning the amplifier began to work correctly, channels were balanced and there were no sound drop-outs, potentiometer noises and other such “attractions”. We also checked the quiescent current. Unfortunately, we were unable to find the service manual and adjustment procedure, but the current was similar in both channels, the amplifier did not distort or get hot when working with 4-ohm speakers, so we simply adjusted the current to the same, averaged value in both channels.

 

 

Once the amplifier was working properly, we moved on to the cosmetic part. The front panel was disassembled and took a long bath in warm water and liquid soap.

 

 

We used that time to clean the rear panel, lid and wash the remaining original knobs. After soaking, the front panel was gently washed with a sponge and thoroughly rinsed.

 

 

Washing should be as gentle as possible to minimize the risk of wiping print. Then the panel was wiped dry and left for an hour to allow the moisture to evaporate from the recesses that could not be wiped.

We also took care of the missing knobs. We could not find original ones at auctions, but luckily we managed to get new knobs with an aluminum finish that visually matched the amplifier and the original knobs that the amp still had. And naturally they were much cheaper than original knobs would be.

After this visit to the beauty parlour (and prosthetic clinic) the amplifier looks completely different. Perhaps not as new, but it’s certainly easy on the eye.

 

 

What can it do and how does it sound? JVC VN-300 is a basic model with low power, 15W per channel. It still has all the standard features. There are 4 line inputs (including a tape loop with double sockets – RCA and DIN) and phono input for a turntable with an MM cart, outputs for 2 pairs of speakers that can be used simultaneously or interchangeably, headphone output derived from power amplifiers (so it can easily drive high impedance headphones), there is even a microphone input. Our only caveat concerns the screws that secure the speaker cables: they are very inconvenient, they must be tightened with a screwdriver, and it is a real challenge to secure even a thin cable. When it comes to controls, we have treble and bass potentiometers, high and low filters, loudness and mono/stereo switches. There are no additional beautifiers in the form of numerous colored lights for various functions, power meters, etc. There’s a single red lamp next to the power switch that indicates that the amplifier is on.

As for the sound, we will describe it as pleasant, decent but not outstanding. The amplifier has good detail, smooth sound and a very good tonal balance, only the lowest bass is a bit lacking (but its quantity is still quite good considering the low power and the fact that it was a BOTL model). The soundstage is more modest (narrower and shallower) than from the Marantz 2215B from the same period, but better than, for example, from a bit more more powerful Technics SU-2300. Phono stage is good and the amplifier handles low impedance loudspeakers without any problems.

JVC VN-300 is a modest but very decent sounding amplifier with good looks and a lot of useful functions. Definitely worth our recommendation at approx. 70 euros. Due to its modest power it is best suited for smaller rooms. It will work great in 15 square meters, up to 25 sq m it will still be fine as long as you don’t listen very loud. Considering its quite neutral sound and narrow soundstage, we advice matching it with small, warm and spacious loudspeakers. Our first choice would beĀ Mission 760 (any version).

 

Technical data:

Model: JVC VN-300
Years of manufacture: ca. 1975
Country of manufacture: Japan

Continuous power – 2x15W at 8 ohms, 2x18W at 4 ohms
Music power – 2x23W at 8 ohms, 2x30W at 4 ohms
THD – 0.5%
IM – 1%
Power bandwidth – 20 Hz – 30 kHz
Frequency response – 20 Hz – 40 kHz +/- 1.5 dB
Damping factor – 30 at 8 ohms
Bass control: +/- 10 dB at 100 Hz
Treble control: +/- 10 dB at 10 kHz
Low filter: -10 dB at 50 Hz
High filter: -10 dB at 10 kHz
Loudness: +10 dB at 50 Hz, +6 dB at 100 Hz
Input sensitivity: line 120 mV, phono 3 mV
S/N: line 70 dB, phono 65 dB
Inputs/outputs: Tape (I/O), Aux 1, Aux 2, Tuner, Phono (MM), 2 pairs of speakers operating alternatively or simultaneously, headphone jack, microphone jack
Power consumption: 60W
Dimensions: 38 x 14 x 30 cm
Weight: 7 kg

 

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