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Building a vintage stereo system

September 5th, 2015

Do you want quality sound system for cheap?

Quality Sound On The Cheap

Unsure on spending high budget on new audio setup? Or are you DIY’er guy who likes to tweak old audio gear?  In all these cases, the second-hand market like eBay and building a vintage stereo system might be a good option to consider.

Current economy brings quite many different audio products (amps, audio and video HD players etc.) for competitive price. However, when it comes not to the marketing but to the quality, the things do not appear so sexy. Especially, if you start to dig the circuits and asses they or the products build quality 😉

During 70s and 80s, the industry was focused on getting extra Hz from audio gear or doing some real HW improvements, until … marketing replaced that.

Before jumping to the considerations of some gear, let’s have a quick look at related advantages and risks of buying some vintage audio gear.

Advantages and disadvantages of vintage gear

First of the advantages is relatively low price for used audio equipment 😉 Especially, if you are good on eBay, you can hunt different pieces for attractive price. That was quite important argument in my case. If you are DIYer, there is plenty of space for different tweaks 🙂 For such reasons, the forums like Audiokarma exist, where people can share&exchange the knowledge about tweaking audio gear. However, you should also realize related risks for buying vintage audio pieces.

Quality Sound On The Cheap

One of the most important is that electrolytic capacitors are ageing. If you look into current higher quality caps specs, you will find that working hours are counted something like ~3000h. We can do some simple math. If someone spends at least two hours daily by listening her/his audio setup, the yearly amount would be roughly ~700h. So, basically that means that each five years, the capacitors should be replaced in order to remain the original specs of the audio system component 😉 Of course, not everyone is so active music listener. However, some audio amps and other components are older than five years in second-hand market.

So, once you get some second-hand audio piece, you should re-asses if the caps need to be replaced.

Some damages of the gear can be related to the parts which mechanically wears (e.g. potentiometers, switches etc.). In some cases, you might fix the equipment without buying any parts (e.g. switches, just cleaninh them). But in some, it can be difficult to source or it might be not very cheap to buy them.

The last limiting factor is the lack of information & reviews on vintage audio. Yeah, yeah… we got used that we can find one million websites writing about some fancy smartphone. However, when it comes to vintage audio reviews, you will be very lucky if you find something useful. Normally, the Internet only started to spread (or even before!) when these products were on sale. So, it can happen that you will not find any written online review 😉

I will conclude, that buying old vintage audio gear is a bit similar to the lottery but the reward can be good. I would like to share my non-exhaustive vintage gear lists which you might consider to get.

Choosing vintage audio amp

Once you start to browse though eBay for a vintage amp, you may come across some descriptions like “rare audio …” etc. Well, you are not directly interested in rare, you are just interested in good audio … 😀

In my case, I short-listed the following amps based on their availability & price on eBay. I tried to find either review or at least some people comments about the sound of each amp. Plus, the features like dual transformer, toroid transformer, remote control, loudness function and using (MOS)FETs were assessed also.

Relatively new models from Denon: PMA-355, DENON PMA-520AE, DENON PMA-720AE, Denon PMA-1520AE and Denon PMA-1560. But according to different sources on Internete, I was not really impressed with their sound quality 🙁
Harman Kardon units E 635i, 650, 645 and 655, but these amps are a bit rare to find. The Rotel amplifiers RA-921 Mk II and RA-931 Mk II sound quite reasonable for that price. However, keep in mind, that they do not posses a remote control.

Quite famous Sony TA ES series across the audiophiles: TA-FA30ES, TA-F500ES, TA-F505ES, TA-F670ES, TA-F690ES, TA-F700ES, TA-FA707ES, TA-F777ES, TA-F808ES and TA-F830ES. And of course, Marantz aplifiers: PM11-S1, PM30, PM45, PM-66SE, PM68, PM78 and PM-80.

Quality Sound On The Cheap

Just remember, that part of these amps were produced before or after early 80s, so they can be without a remote control. That was quite usual during those days 🙂

After long considerations, I decided to go for Marantz PM-66SE. As I wrote one important thing is to asses the electrolytic caps. But it is the same important that both channels of the amplifier are producing the same volume of the sound. That is achieved by adjusting the idle current of the last stage of the amp. Once its output current was adjusted on mine PM -66SE for both channels (I strongly suggest to do after buying whatever brand amplifier), I was astonished by its sound 😉

Choosing vintage speakers

Of course, you might stick to a specific brand & model. But I would recommend just to do ‘windows shopping’ by using the keyword ‘vintage speakers‘. Well, the reason is quite simple. You might come across something about what you did not know even in advance 🙂 That’s how it happened for me.

I found Mordaunt Short MS35Ti speakers, which are two-way speakers with following specs:
Nominal impedance: 6 Ohms
Bass Unit: 200mm cone (DSB 193)
Tweeter: 19mm titanium dome
Amplifier requirement :10 – 300watts per channel
Sensitivity: 88dB for 1w at 1m
Maximum S.P.L.: 113dB peak
Dimensions: 490mm x 260mm x 275mm
Finish: Black Ash

I was curious to see how parameters of the speakers are different. The serial numbers of the bass units were very close. I also checked the inductance and the resistance of the tweeter and the bass units. There were within 5% to each other.

Mordaunt Short company was a British company which produced good quality speakers until they were acquired by Tannoy. After that, Mordaunt Short became only a product range name.

At the end …audio system bottle neck principle

When you are building your vintage audio system, just remember the bottleneck principle. Accordingly, the sound source plays an important role too.

Quality Sound On The Cheap

If you use a PC-based HTPC, I would recommend to get M-Audio Audiophile 2496 sound card. It might cost ~30 GBP, but it is worth every penny. I already wrote a bit about it in my previous post on re-building HTPC. However, just remember that this used card may require re-capping the electrolyte caps. That was the case with my 2nd sound card.

Adding FET-based audio pre-amp might also drastically improve the sound 😉 I read somewhere that one guy used it twice before the power amplifier input and after sound volume control. In my case, I use it only once before the amplifier but it makes the sound a lot more pleasant to listen.

Enjoy a good sound for cheap!