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Quad II rebuild/modification

G

guydarryl

pfm Member
Hi,

I have had a pair of Quad II's sitting in my loft for about 40 years (in bits). And having a clear out have considered two possibilities:

  • sell
  • have them rebuilt to work with a passive pre and separate phono stage.
Rebuild really appeals but would involve a few modifications (earthing for one thing!).

Do any members have experience of having Quad II's rebuilt and feel able to recommend a company to carry out the work?

Regards. Guy.
 
If they are cosmetically decent I’d only consider getting them properly restored to original function, which isn’t really suitable for a passive preamp as they are pretty insensitive. You’d need to modify the input stage to get passive compatibility and that would involve spending money on non-standard tweaks that would make them worth less than they are unworking in parts now! I’d just get them sympathetically rebuilt to original spec and then budget for a nice little preamp, e.g. the most basic Croft would be a good option.
 
Thanks for advice Tony,

I do have a Meridian 101 pre hidden away, would this be more suitable do you think? (I also have a Quad 22, but I was thinking of selling that to partly fund the restoration - also hasn't got the plug in modules and is very tatty).
If running the Quad II's from a different pre, don't they need an earth connection, as I understood that they connect to earth via the 22?

Any other members have the name of a suitable restorer - there seem to be a few on the internet, but I would appreciate the benefit of other peoples experiences in choosing one.

Regards. Guy.
 
I’ve never owned a Quad II system so don’t know the fine detail, but as I understand it the Quad 22 is powered from the power amp, not a true separate like say a 33, as such the earthing has to be done via the II power amp, surely? I’d expect the standard three-pin Bulgin mains connector to provide a chassis earth as it does on similar kit from Leak etc. As far as I’m aware all you need to use a pair of refurbished but 100% stock spec Quad IIs with any modern preamp is a Jones Connector to RCA plug adapter for each amp. Others here know more about these fine amps than I do though.

PS I’ve always really fancied a full set including the preamp and tuner, it is only the price of good NOS KT66s that has put me off!
 
Quad II has an input sensitivity of 1.4vrms and a very high input impedance. On the face of it this would be ideal for passive pre use with modern sources. One wrinkle is that it is dc coupled so some care may be needed with sources.

IIRC the earth for the Quad II comes down the signal cable. The Quad 22 has a captive mains lead and two switched mains output leads and two signal out/power back leads. So four leads to the Quad IIs, which get powered on and off depending whether you are listening to stereo or mono. The 22 takes is power from a power amp and routes it on to the tuner connectors when they are selected.

It's quite common to replace Quad II connectors so you have a switched IEC mains inlet and a phono for signal replacing the two pin Bulgin, the Jones socket and the fuse/voltage selector arrangement. As using the pre and the tuners is uncommon this makes the power amps safe and convenient. I think it can be done more or less reversibly and doesn't make any demands on the internals which can (and should) remain mostly standard.

As usual Keith Snook has loads of info. http://www.keith-snook.info/quad-ii-valve-amplifier-mods.html
 
Audioflyer (Sharif) of this parish has done a lot of work with Quad 22s and 11s. He may be able to offer useful advice.
 
Arkless Electronics said:
I've rebuilt probably 15 or so pairs of Quad II's over the years.... Why are these in bits has to be the first question?
Click to expand...

I was young and foolish!

I bought them when I was about 18 (42 years ago), thought that I would give them a respray to touch them up a bit and haven't been used since.
 
Tony L said:
If they are cosmetically decent I’d only consider getting them properly restored to original function, which isn’t really suitable for a passive preamp as they are pretty insensitive. You’d need to modify the input stage to get passive compatibility and that would involve spending money on non-standard tweaks that would make them worth less than they are unworking in parts now! I’d just get them sympathetically rebuilt to original spec and then budget for a nice little preamp, e.g. the most basic Croft would be a good option.
Click to expand...

Agreed, a wonderful amp if restored sympathetically and relatively easy restoration to do as there is plenty of excellent guidance online. 50 years old and no reason why they won't last another 50 years when complete.
Parts readily available from such as Paul Greenfield of Classic Sounds who has a good stock of those excellent Russian paper in oil capacitors and will supply a full refurb kit of caps and resistors.
Transformers and chokes can be rewound by such as Majestic or Mike Barker in Devises.
Valves are key and KT66s by GEC, Marconi and Osram although plentiful are a little expensive. Nevertheless they will last for many years and will add to the listening pleasure and residual values. Good cheaper alternatives are readily available.
Improve cosmetics by spraying with Rover Metallic grey from Halfords.
As an owner of Quad IIs I also used to share your concern about lack of earthing until it was pointed out to me that this is taken care of by the interconnects and that only one earth is needed in the daisy chain of your set-up; otherwise you run the risk of earth loops and unwanted humming. This got me into the habit of never powering up any system until all connections have been made and ensuring that one of those components is earthed.

Have you dismissed the idea of using the original Quad 22 preamp? This last 2 weeks I have refurbished 4 of them and have been pleasantly surprised as to how good this user friendly. full featured preamp with its exceptional build quality performs. With modern components fitted maybe better than the original. One of the 4 had previously been modified whereby the pair of EF86s had been replaced with solid state circuitry and an additional input for CD had been added. Yes its good but I can't honestly say that its worth the bother. To play CD on the unmodified 22 I just use the tape input - excellent, looks the part and retains its value.
 
Hi Disco,

not entirely dismissed the 22, just trying to keep cost down - back story to the situation:

Wife wants to clear up the house (understandable; I have quite a few bits and pieces. Although they don't take up as much space in storage as daughters old teddy bears, doll's houses etc - daughters now 18 and 25!).
Being honest with myself I know that I will never put the amps back together, but I still have very happy memories of using them for a few years.
So, idea is to sell a few bits and pieces (including 22 ?) to fund repair/refurbishment of II's and be able to use them, occasionally, with my passive and phono amp - benefits: could be self funding, amps not being wasted and wife pleased with my gesture ;)

However, the idea of getting the whole lot up and running does appeal - even my wife agrees that they look lovely (she has never heard them though, I think that if she did that could persuade her to see the sense in my keeping them).

Sorry for the ramble, just getting things straight in my own mind to an extent. If were to go down the route of a complete rebuild I have a few amps (2 x Denon 350 SE, 1 X Nait 3) and other bits to help fund the project.

Question still stands - any other suggestions for good engineers and approx' cost, or do I just chance my arm with one of the advertised services?

Thanks for the suggestion of Ampregen, will look that up.

PS - I have quite a few GEC KT 66 (used but carefully packed away) so, hopefully, there should be enough in working order for both amps and a couple of spares.

Guy.
 
I had my Quad IIs rebuilt by Graham Tricker at GT Audio 20 years ago. They stayed in my system untilI bought one of GT's high end TRON Voyager SET amplifiers for a LOT more money.

I have also had Henry Dulat (toprepairman) in Leatherhead repair some of my equipment (a Revox valve based G36 R2R). He was excellent and reasonably priced.

I'm sure that Jez (Arkless) or Graeme could do an excellent job as well
 
guydarryl , If you're confident that the transformers and chokes are sound why not take them to be overhauled by Quad themselves at Huntingdon. They did a first-rate job on my valve set-up a few years back and prices were very reasonable.

BB
 
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