Tuesday, February 10, 2009

A Vintage Euro Pair

European made components are rare in the US. I recently restored two small, presumably late '60s integrated amplifiers. Their construction is significantly different from Japanese components, but of high quality.

The first is a Dual CV 40:

Dual is very well known in the US for turntables, but I have never seen a Dual amplifier other than this one. I am not sure Dual actually was the manufacturer, and wonder if this is a actually a relabeled Braun. The CV 40 is presumed to be about 20 watts per side.

Here is a view of the innards:

This is a very simple amplifier, but built with very high quality components. Caps were for the most part axials of values not commonly used today. I left intact the very nice power supply cap bolted horizontally to the inner frame. I replaced each of the main filters just behind the heat sinks and strapped them with a Russian made polystyrene cap as a bit of a tweak.

Note: the Dual's potentiometers at the top of the photo above are of very high quality with cast frames.

Next is the Philips 520 amplifier, with marvelous pair of round meters at the left of the unit:

Balance, bass and treble are sliders at the middle of the unit. Here is the amp with the top off:

This amp was roughly as simple as the Dual, but with a nice helping of film capacitors, in yellow above. I replaced and beefed up the main filter capacitors at the left of the photo above. The phono section is at the right of the board. The modest number of Philips electrolytic caps replaced were kind of cute:

Both amplifers sounded great after restoration, despite, or perhaps because of, very simple contruction. Solid state gear manufactured in the 1960s typically has a poor sonic reputation, but these ended up as smoothly musical with a nice helping of slam. It is not clear to me that this early gear truly sounded bad when new, nor does this seem reasonable for all cases. It is not surprising that early designs were relatively unsophisticated. However, unsophisticated is not necessarily bad. The audiophile beloved Advent 300 is a simple design that sounds great. Proper evaluation of vintage gear needs to be done with restored units. An amplifier with 40 year old capacitors will not sound nearly as good as when new.

On the other hand, it should also be pointed out that the replacement of aging capacitors with new can never exactly reproduce the original circumstances of manufacture. Modern caps have tighter tolerances, lower ESR, and in many instances cannot be found in the same voltages as the original caps. For example, Panasonic FCs of 10 mfds or less are available in 50 volts or more where lower voltages might have been used in a vintage component. To complicate matters, I tend to use higher voltage caps in general, especially in power supplies. And beyond that I often increase the capacitance value itself in power supplies. Typically, restored power supplies have a better foundation than as manufactured. Occasionally I add a tweak as described above, sonic value unknown.

The build quality in 40 year old components tends to be much higher than that found in contemporary consumer audio gear. I am of the opinion that the conventional wisdom that early solid state components are not worth restoring is often incorrect, and that these vintage units need to be restored before rendering judgment. Both the Philips 520 and Dual CV 40 amplifiers are worthy restoration candidates.


River said...

well l for one have a number of old
sets from the 60s and 70s,including the record player and cassette deck with built-in amp l had as a kid back then.Both were of Philips make,they still sound good now,despite the record player having strange speakers in which the magnets are at the front.Just seemed a shame to chuck them,l still use both regularly!A good one's certainly worth preserving,as
you say build quality was much better then than now.

Kenny said...

I have one of these, which I won on Canadian Ebay for $.99 plus shipping. The unit works, but after a few minutes develops a rushing, hissing sound which can be distinctly heard on all sources. I'm not well versed on solid state gear. Any ideas on this?

Anonymous said...

I picked up a Philips 520 amp the same as the pics above off the side of the road.
The amp is in good working condition.
It also has a matching turn table.

Do either of these have any dollar value ?

Nat said...

The Philips turntables are bang for the buck sonic bargains. The units I am familiar with employ a version of the classic AR suspension. They might seem just a bit flimsy compared to some but sound wonderful. Purchased retail from a reputable shop expect to pay $100-$250 depending on model and condition.

But no doubt you are interested in what they will bring to you. Essentially this translates into: what can I get via ebay? These seem to show up fairly often so just surf the 'bay a bit and you will be able to determine a value. But ebay isn't retail, so figure on $25-150 depending on model, condition and the quality of your presentation.

The amp is an interesting problem. Restored I think they are well worth $150-250. They sound great and look great, but they are now 40 years old and it will be a bit of a miracle if they work. The clock is ticking on the capacitors and these amps will sound scratchy and muddy until properly restored. Expect $30-60 as is.

Kenny said...

I got my CV40 working nicely and mated it with a Dual CT 15 tuner (from Ebay Germany) along with a Dual 1219/Ortofon OM10 'table & cart combo. Speakers are a pair of very efficient Jensen TF3's from the early 60's which I recapped. The rig sounds quite refined and very musical.
Someday I'll get my Scott 340 working properly again...

Nat said...

Kenny: very nice rig. I am not familiar with the CT 15, nor the TF3's. The TF3's seem to be well thought of from nosing around the forums. Recapping a speaker this old is a must to make them sound right. Getting boutique-y with caps can sometimes be counter productive, low esr film caps cap can lead to hot tweeters. Some of the old Advents really need electrolytics. But it's always worth giving film a try.

I have two pair of Jensen TF4's, 'slender bookshelf' 4 way speakers. Butt ugly, I must say. Whipped. But with very high quality drivers and crossover. They have been on the to-do list for years, I am afraid, they need some serious tlc. But I couldn't pass them up. Twice.

Anonymous said...

Looking for a 520 or 720 philips amplifier or a similar philips vintage amplifier.
Please let me know at ardonedgar@yahoo.com
Thank You

Anonymous said...


I have a CV 40, of which the right output is no longer working; the two gray resistors near the mosfets on the right side look burned and the fuse of the right side is broken. I suspect the 2 mosfets on the cooling block, but i have no idea what would be a compatible counterpart these days, please share!

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