Any love here for german Dual amplifiers?

[smoking-rob]

I am talking about models such as the CV20, CV30, CV40, CV60 but there are others from that era, end of 60's, beginning of 70's.

Since I have been using them I find it impossible to return to a "straight line"amplifier. These Duals have a built in (but defeatable as well) and volume position dependent "contour" or loudness circuit that gives the sound fullness and body that, to my ears, is very appealing. If the contour addition is too much, you can accordingly adjust the bass and treble controls

The CV20 has very limited power output but has a fine and delicate sound, best used with high efficiency speakers.

The CV40 has a quite decent power output (for those days) and would be alright with most speakers with a minimum efficiency of 88,89 db.

Soundwise, a CV30 tops these two models with more snap and transparency to the sound, a CV60 is about the same but with more power.

I use all 4 models (alternatingly) with a pair of Dutch speakers from the 80's, Translator Impact 2, great synergy.

Beware that most units will need some sort of servicing now including a recap.

 

[toprepairman]

The amplifier section is a fairly simple and crude 6 transistor(1 for bias), quasi complementary capacitor coupled output.
Nothing really wrong with that and a testament to how a simple circuit can give great results. Very easy to fix if it gets blown up.
The 'Golden Ears brigade' may imagine, er sorry may detect a bit of crossover distortion but a double blind test will most likely dispel that particular myth.

 

[mandryka]

But what is this loudness circuit that the OP mentioned?

 

[MikeMA]

Gosh, this takes me back a long, long way. My first hi-fi amp was a Dual CV60 and matching CT17 tuner, purchased in West Berlin in the late 1970s, along with a pair of Leak Sandwich speakers. They looked just like this, though not my pics:

I also had a Thorens deck and Akai cassette player.

When I returned to the UK I was persuaded to "upgrade" the Dual kit for a Quad33/303/FM3. Was it really an upgrade? I can't remember, but I do remember missing the Dual Liner/Contur loudness switch, especially at party time!

Edited to include pics.

 

[hp1]

A friend had a cv1150? with a 505 tt and aurex micro monitors and I have to say it was a bloody musical happy little set up.

 

[smoking-rob]

But what is this loudness circuit that the OP mentioned?

A built in "contour" whose effect decreases as the volumepot is increased in its travel, so a boost in (mostly) bass and treble frequencies, but a lot more refined and musical than the usual "boom and tizz loudness switch on more modern amplifiers.

Bear in mind that these amps were likely designed with the smallish Dual speakers of the day" in mind so they benefitted from that contour sound plus, as said, it can be defeated (usually by pulling out the volume knob) but then they sound quite thin and nothing special.

 

[smoking-rob]

A friend had a cv1150? with a 505 tt and aurex micro monitors and I have to say it was a bloody musical happy little set up.

That would be a Dual amp from the eighties and likely outsourced to a japanese manufacturer and without the aforementioned "contour", possibly built to lower standards as well.

 

[smoking-rob]

When I returned to the UK I was persuaded to "upgrade" the Dual kit for a Quad33/303/FM3. Was it really an upgrade? I can't remember, but I do remember missing the Dual Liner/Contur loudness switch, especially at party time!

Well, before the Duals came into my possesion, my amps were by Hiraga (Le Classe A and Lectron pre) so no slouches. But returning to them after having adjusted to the Dual "sound", I found them thinnish and less musical (probably more hifi though but I just didn't enjoy the music as much anymore). I subsequently sold them off.

The Dual phono section is also very good (I have compared it to my Whest PS20, yes a little better but not by very much)

 

[Martyn Miles]

I recall a Sony TA1010 amp. I owned had a 'Loudness' switch, linked to the volume level. It worked very well with my Goodman's Minister speakers, for low-level nightime listening.
Ah, those Ministers. Lovely speakers...

 

[cubastreet]

If you come across a dual idler turntable from around the same time, they're great too.

 

[Hazelberry]

If you come across a dual idler turntable from around the same time, they're great too.

I gave a friend 70s Dual I found very cheaply in a second hand shop. Put a cheapo cartridge on it (can't remember what) that I had in my box of spares, and it worked well through her Denon receiver and wee Mission standmounts. Later, through her boyfriend's expensive system with a very nice separate phono stage, it sounded fantastic, actually blew me away.