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Quad ll original and Classic

Ianp

Ianp

pfm Member
I own a Classique restored pair of original Quad IIs and will be taking delivery of a pair of the Classics tomorrow, which I plan to replace them with.

These are the initial production lighter olive colour as opposed the the later grey, and there's no more thinking to the exchange other than they look gorgeous, have modern connectivity and will match my QC24 pre, so yes, I'm superficial on two of those counts :).

Is this the move of heresy ? Chinese made reproductions over originals. Frank and robust responses welcome !
 
I have a restored pair of original Quad IIs, with modern connectivity. I had the same thought as you, to buy a modern pair to replace them, but the old amps are utterly reliable, with no self-noise or speaker hum. I've only replaced a rectifier tube. This is so unlike other, modern tube amps I've owned, that I can't make a case to replace them.
 
Ianp said:
I own a Classique restored pair of original Quad IIs and will be taking delivery of a pair of the Classics tomorrow, which I plan to replace them with.

These are the initial production lighter olive colour as opposed the the later grey, and there's no more thinking to the exchange other than they look gorgeous, have modern connectivity and will match my QC24 pre, so yes, I'm superficial on two of those counts :).

Is this the move of heresy ? Chinese made reproductions over originals. Frank and robust responses welcome !
Click to expand...
its a good question,but personally would of done the research before buying the modern ones....
Would be interesting for you to do a blind tests,swapping the valves....
All that glitters isnt always gold...
 
Quad74 said:
its a good question,but personally would of done the research before buying the modern ones....
Would be interesting for you to do a blind tests,swapping the valves....
All that glitters isnt always gold...
Click to expand...
Fair call, but I tend to be more impetuous. My findings care that the Classics are a little more snappier/transparent than the old chaps. They're stunning amps.
 
Are they? My impression was that the build quality was abysmal and it was a theft in the light of day for the price they were sold to dumb public.
 
Pirx said:
Are they? My impression was that the build quality was abysmal and it was a theft in the light of day for the price they were sold to dumb public.
Click to expand...
I'd have to ask if your impression is from first hand experience ? My findings don't align with it.
Mine are the older olive colour, though I have first hand knowledge of a very poor experience with the new production ones via a friend.
 
Ianp said:
Fair call, but I tend to be more impetuous. My findings care that the Classics are a little more snappier/transparent than the old chaps. They're stunning amps.
Click to expand...
The marketing...
The QUAD II Series circuit design is the work of Tim de Paravicini, a man widely acknowledged to be the UK’s foremost valve amp designer. His design is faithful to Peter Walker’s Philosophy of cathode loading onto the same output stage and fundamental simplicity of design, ensuring the new amp delivers the same wealth of detail and exquisite tone as its famous predecessor.
The Measurement....
THD at 50Hz not to exceed 0.25% This is optimistic and more often >0.7% ~ But still much better than the 'QUAD II Classic' and later versions made by IAG using the QUAD name
 
Hi All

I own a pair of the Chinese manufactured QUAD II Classic monoblocs. To my eyes they are actually well built especially when compared to some of the stuff that comes from that part of the world. The basic circuit is the same as the original QUAD II with the exception of some capacitor values used in the power supply and a couple of extra components to confirm to modern codes and standards.

On my units, the first PSU smoothing capacitor is 82uf / 500V where the original was 16uf / 450V, the second PSU smoothing Capacitor fitted after the choke is 150uf / 500V where the original circuit called up 16uf / 450V. The voltage rating on the cathode capacitor has also been increased, QUAD now use a 47uf / 450V rather than the original 25uf / 25V, it's overkill on the voltage rating but it won't hurt anything. There is also a 100pf capacitor added across the control grid to earth on both of the KT66's This should improve noise rejection and is probably driven modern EU regulations around noise suppression and susceptibility to external interference. Also, on the modern units the output transformer appears to be optimised for an eight-ohm load (check out Art Dudley's review in Stereophiles for a full set of measurements). If Tim "de-P" did have any input into this circuit it would only have been how to make it meet modern EU standards, the basic circuit is original, and this is a good thing.

My units have been quite reliable and perform very well the only issue I have ever had is a failure of One KT66 after transporting the units, a fault with the valve rather than the amplifier itself along with a carless removalist, even though the units were packaged in the original boxes. The failed tube was not one of the original QUAD branded tubes but a JJ's KT66 as the original QUAD branded tubes are now boxed up and in storage with only a few hundred hours of usage. The QUAD circuit is pretty easy on the output tube and many thousands of hours can be expected from this circuit, quite a few original QUADs are still using the output tubes that were fitted when the amplifiers left Huntingdon.

However, I have heard that some reliability issues are starting to appear in the later built units. My units are the gold-beige colour and have serial numbers 0415 and 0416, they are a reasonably early build. I believe at this stage IAG (who now own the QUAD name) had QUAD people flown to the Chinese facility to watch over the first couple of builds and I think mine were made during this period. I also believe that at this stage the transformers were still wound in Huntingdon, I think. Production of the later builds which are now grey rather than the gold-beige colour has been going strong for some time, but I have heard some comments about reliability. Its only anecdotal but it would be good to hear form other members who have had experience with the later built, grey painted units. I know I participated in a thread where another PFM member was having issues with a newly purchased failed unit.

Happy Listening

LPSpinner.


PS: The Late Art Dudly concluded his review of the QUAD II Classic monobloc by saying,
... For its part, the new Quad II Classic is like finding a wormhole in the time-space continuum and going back to the Cavern Club of 1962. Or, to paraphrase Ken Kessler paraphrasing Quad themselves, this is the closest approach to the closest approach. Go buy a pair of these, use a bit of nail-polish remover on a cotton ball to remove the silk-screening, and live it up—life is brief, and second chances are thin on the ground.
 
thanks for sharing this,interesting;)

LPSpinner said:
Hi All

I own a pair of the Chinese manufactured QUAD II Classic monoblocs. To my eyes they are actually well built especially when compared to some of the stuff that comes from that part of the world. The basic circuit is the same as the original QUAD II with the exception of some capacitor values used in the power supply and a couple of extra components to confirm to modern codes and standards.

On my units, the first PSU smoothing capacitor is 82uf / 500V where the original was 16uf / 450V, the second PSU smoothing Capacitor fitted after the choke is 150uf / 500V where the original circuit called up 16uf / 450V. The voltage rating on the cathode capacitor has also been increased, QUAD now use a 47uf / 450V rather than the original 25uf / 25V, it's overkill on the voltage rating but it won't hurt anything. There is also a 100pf capacitor added across the control grid to earth on both of the KT66's This should improve noise rejection and is probably driven modern EU regulations around noise suppression and susceptibility to external interference. Also, on the modern units the output transformer appears to be optimised for an eight-ohm load (check out Art Dudley's review in Stereophiles for a full set of measurements). If Tim "de-P" did have any input into this circuit it would only have been how to make it meet modern EU standards, the basic circuit is original, and this is a good thing.

My units have been quite reliable and perform very well the only issue I have ever had is a failure of One KT66 after transporting the units, a fault with the valve rather than the amplifier itself along with a carless removalist, even though the units were packaged in the original boxes. The failed tube was not one of the original QUAD branded tubes but a JJ's KT66 as the original QUAD branded tubes are now boxed up and in storage with only a few hundred hours of usage. The QUAD circuit is pretty easy on the output tube and many thousands of hours can be expected from this circuit, quite a few original QUADs are still using the output tubes that were fitted when the amplifiers left Huntingdon.

However, I have heard that some reliability issues are starting to appear in the later built units. My units are the gold-beige colour and have serial numbers 0415 and 0416, they are a reasonably early build. I believe at this stage IAG (who now own the QUAD name) had QUAD people flown to the Chinese facility to watch over the first couple of builds and I think mine were made during this period. I also believe that at this stage the transformers were still wound in Huntingdon, I think. Production of the later builds which are now grey rather than the gold-beige colour has been going strong for some time, but I have heard some comments about reliability. Its only anecdotal but it would be good to hear form other members who have had experience with the later built, grey painted units. I know I participated in a thread where another PFM member was having issues with a newly purchased failed unit.

Happy Listening

LPSpinner.


PS: The Late Art Dudly concluded his review of the QUAD II Classic monobloc by saying,
... For its part, the new Quad II Classic is like finding a wormhole in the time-space continuum and going back to the Cavern Club of 1962. Or, to paraphrase Ken Kessler paraphrasing Quad themselves, this is the closest approach to the closest approach. Go buy a pair of these, use a bit of nail-polish remover on a cotton ball to remove the silk-screening, and live it up—life is brief, and second chances are thin on the ground.
Click to expand...
 
The thread about the faulty pairs was started by a friend of mine, in brief he had one bad pair replaced by another and then a refund.
 
Going back to the original post, IanP mentioned that he was looking at the lighter olive colour so I am assuming that these are a second hand early build. If they were going to fail they probably would have done so by now. The only thing you might want to do at some point is get a new set of KT66s and put the original tubes away so you can sell it on later with the original tubes, collectors like that sort thing so it could increase the resale value.

The afore mentioned QC24 line level preamp is also a very nice unit and probably the best match for the QUAD IIs. As a combo they work very well musically and visually. This is a Tim de-P design and is a remarkably simple Anode coupled, one valve stage that sounds allot better than it should. It does have a high(ish) output impedance so it won't always play nice with modern solid state gear but it works a treat driving loads above 100Kohms. Vintage valve gear is where it will shine. It's actually a good way of interfacing modern high output sources with classic tube designs as many older tube preamps are way too sensitive to comfortably handle a 2 Volt line level signal.

Back to talking about build quality, To my eyes the Chinese made units actually look better than the Originals, sad but true.The transformer cases are fully seal welded and linnish back to a seamless finish and the piant does have a much nicer level of gloss than the original sixties built units. Inside, my units are nicely constructed using fibreglass board for turret board section on the input circuit and point to point wireing for the rest of the circuit, just like the originals. The newer builds can look a little more busy inside but that's because the Chinese made units are using heavier gauge wire than the originals.

It's also very difficult to do a meaningful comparison sound wise, of the Chinese made QUADs to the sixties originals as a the condition of the originals will vary greatly between samples. Many of the originals have been modified with the intention of improving the sound and so destroying the original character, but that's another subject entirely and I'm not going there....

LPSpinner.
 
Ianp said:
The thread about the faulty pairs was started by a friend of mine, in brief he had one bad pair replaced by another and then a refund.
Click to expand...
Yes I remember that thread, it's good to hear he got it sorted. I hope he is happily enjoying his tunes now...
 
LPSpinner said:
It's also very difficult to do a meaningful comparison sound wise, of the Chinese made QUADs to the sixties originals as a the condition of the originals will vary greatly between samples. Many of the originals have been modified with the intention of improving the sound and so destroying the original character, but that's another subject entirely and I'm not going there....

LPSpinner.
Click to expand...
I meant to add that that's a very good point that I'd not really considered. My originals haven't been modded but have had a complete rebuild.
 
LPSpinner said:
Yes I remember that thread, it's good to hear he got it sorted. I hope he is happily enjoying his tunes now...
Click to expand...

I did have a terrible time with the Quad II Classics but am now happily enjoying a serviced vintage pair with original valves. My current pair have mains switches and Bulgin mains sockets added via the fuse cutout.

Incidentally, the QC24 was designed by Andy Grove along with the Quad II-40 as mentioned in KK’s review of the pairing, pre-dating Tim de P’s involvement with Quad by some years.

L6Jrl1O.jpeg
 
LPSpinner said:
Going back to the original post, IanP mentioned that he was looking at the lighter olive colour so I am assuming that these are a second hand early build. If they were going to fail they probably would have done so by now. The only thing you might want to do at some point is get a new set of KT66s and put the original tubes away so you can sell it on later with the original tubes, collectors like that sort thing so it could increase the resale value.

The afore mentioned QC24 line level preamp is also a very nice unit and probably the best match for the QUAD IIs. As a combo they work very well musically and visually. This is a Tim de-P design and is a remarkably simple Anode coupled, one valve stage that sounds allot better than it should. It does have a high(ish) output impedance so it won't always play nice with modern solid state gear but it works a treat driving loads above 100Kohms. Vintage valve gear is where it will shine. It's actually a good way of interfacing modern high output sources with classic tube designs as many older tube preamps are way too sensitive to comfortably handle a 2 Volt line level signal.

Back to talking about build quality, To my eyes the Chinese made units actually look better than the Originals, sad but true.The transformer cases are fully seal welded and linnish back to a seamless finish and the piant does have a much nicer level of gloss than the original sixties built units. Inside, my units are nicely constructed using fibreglass board for turret board section on the input circuit and point to point wireing for the rest of the circuit, just like the originals. The newer builds can look a little more busy inside but that's because the Chinese made units are using heavier gauge wire than the originals.

It's also very difficult to do a meaningful comparison sound wise, of the Chinese made QUADs to the sixties originals as a the condition of the originals will vary greatly between samples. Many of the originals have been modified with the intention of improving the sound and so destroying the original character, but that's another subject entirely and I'm not going there....

LPSpinner.
Click to expand...
Also have to wonder how many people actually have them on the right tap for the relevant speaker impedance....
 
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