advertisement


Pre-amp suggestions for a Quad 303 please

You must have had a later one with upward facing caps, my original one spewed it's cap contents downwards all over one of the amp boards - that memory is the main reason I sent this one back to Quad for a full service before using it!

Don't worry about this as there is a kit from Quad to convert the caps to the later arrangement. (There used to be as I bought one and did the changes).

If the caps haven't been changed from the originals I would say that it is imperative that new caps are fitted for sound quality reasons and avoiding the corrosive chemical dump as described by Tony. If the output caps fail there is also the chance of damaging your speakers. Having said that It is more likely that the power supply caps will go first as they are more stressed.
 
Don't worry about this as there is a kit from Quad to convert the caps to the later arrangement. (There used to be as I bought one and did the changes).

5946357528_b1a2d091da_o.jpg


They don't seem to bother flipping them any more, my current 303 is a very early 'MkI' with a four digit serial has never leaked and when it came back from it's service with new (physically much smaller) PSU caps fitted they were in the original orientation.
 
I recently bought output and power caps from Quad and no mention was made of reversing their mounting.

Out of interest the caps in Tony's amp look to be BHC which are excellent, Quad are now using Vishay BC @ 2200uf 100v. I think the only reason for change is that BHC at that capacitance are no longer readily available.
 
Interesting. Thanks Tony.

I have had one weird incident with it since the service that I can't explain. I tried the 33 a few months ago out of curiosity just to see if it worked. It kind of does, kind of doesn't, i.e. music comes out, but so does a fair amount of hiss and crackling, and when I turned it off I got a pretty loud farty noise through the Heresys. After that when I reverted to my usual passive the 303 started intermittently fading out on the right channel, not 'off', it just got quieter. I took it out and ran my spare Rega Brio for a week or so, but then thought I'd try the 303 again. Since then it's been fine. I've no idea what occurred, but it certainly seems to be working ok again now. It certainly should be ok as the service was only about 3 years ago!

PS I've tried the 303 in both systems, it really sounds excellent between the Croft 25R pre and Tannoy Monitor Golds, a rather lighter, smaller more mid-centric presentation than my Leak Stereo 20, but I could very happily live with it. In fact I probably will in the future if I ever slim-down to a single system as it would be so much more economical to run than a full tube rig.
 
I bought a 33/303 last year along with some ESL57 speakers. I got them both serviced and re-capped by Quad and they sounded a lot better when they came back.

The tone controls and filters were very handy on the 33 and I loved the styling but when I compared to my Croft Basic, I could hear that the preamp was limited. The Croft added 'that' signature warmth to the sound but apart from that I could hear much more detail than with the 33.

Next was Croft vs Promitheus TVC preamp. I would have loved to have kept both but there was such clarity with the TVC, the Croft was sold.

Finally M-DAC in preamp mode vs through the TVC. Too close to call and the cost of the M-DAC meant I had to sell the TVC.

In my system, less between source and the 303, is more.
 
Interesting Mr Eckythump! I was just looking at the Croft micro basic with the MM phono stage. I may have to scour the ads for one secondhand...

I was also considering the cheaper / older Linn pre-amps - does anyone have a view on these and their potential suitability to partner my 303?
 
I recently bought output and power caps from Quad and no mention was made of reversing their mounting.

Out of interest the caps in Tony's amp look to be BHC which are excellent, Quad are now using Vishay BC @ 2200uf 100v. I think the only reason for change is that BHC at that capacitance are no longer readily available.

My quad service sheet says,

Early versions of the Quad 303 ave the 2200 caps mounted tags down, blah, blah, it is advisable to invert the electrolytics, blah, blah A kit providing tag board and extensions to the wiring harness is available. Order stock number Q03CAPI.

Newer caps are more reliable in the seal area so they must have decided not to bother.
 
Newer caps are more reliable in the seal area so they must have decided not to bother.

It seems common practice these days with most modern amps having their caps face down and soldered straight onto the main circuit board from what I can tell from looking at the odd pic here and there, e.g. that's how they are in a Quad 306, and I suspect that gets a lot hotter in typical use than the very well ventilated 303.
 
Newer caps are more reliable in the seal area so they must have decided not to bother.

It seems common practice these days with most modern amps having their caps face down and soldered straight onto the main circuit board. That's how they are in a Quad 306, and I suspect that gets a lot hotter in typical use than the very well ventilated 303.
 
A point to note on the Croft was the amount of gain. Mine had been modified with a switch to reduce the amount of gain when using CD etc. I think in its' standard form you may end up with too much gain for the 303 and not have much play in the volume control.

I'm sure others here will be able to clarify if that is the case.
 
A point to note on the Croft was the amount of gain. Mine had been modified with a switch to reduce the amount of gain when using CD etc. I think in its' standard form you may end up with too much gain for the 303 and not have much play in the volume control.

I'm sure others here will be able to clarify if that is the case.

I forgot to mention my Croft has a gain reduction in order to be at least vaguely usable with my Leak Stereo 20, which has an input sensitivity of just 125mV for full output. Even so in this context the Croft is still pretty loud at 1 o'clock on CD (it starts at 12 o'clock!), though is far more usable with the 303 which has a 500mV input, I actually get a bit of range to play with there.

As someone who listens fairly quietly I find the whole culture of hi-fi gain ridiculous. Most kit is very obviously into clipping within a third of the volume knob travel. Do they really think we are stupid enough to falsely equate knob position with headroom / amp power? It's both mad and intensely irritating IMO.
 
I forgot to mention my Croft has a gain reduction in order to be at least vaguely usable with my Leak Stereo 20, which has an input sensitivity of just 125mV for full output. Even so in this context the Croft is still pretty loud at 1 o'clock on CD (it starts at 12 o'clock!), though is far more usable with the 303 which has a 500mV input, I actually get a bit of range to play with there.

As someone who listens fairly quietly I find the whole culture of hi-fi gain ridiculous. Most kit is very obviously into clipping within a third of the volume knob travel. Do they really think we are stupid enough to falsely equate knob position with headroom / amp power? It's both mad and intensely irritating IMO.

You've only got to look around at various threads on here and elsewhere, where people say things like.....it's so loud even at 10 o'clock on the volume control, so I've got plenty to go... or similar.

The idea of the amp that goes to 11 is alive and well on these fora.

S.
 
It seems common practice these days with most modern amps having their caps face down and soldered straight onto the main circuit board. That's how they are in a Quad 306, and I suspect that gets a lot hotter in typical use than the very well ventilated 303.

Yes it certainly does.
Idling current due to the Class A section gives 30w consumption just for doing nothing.
 
Caps are more reliable these days as there should be a seal that can cope with high temperatures and also there is usually a vent or a weak spot on the aluminium case which allows a failure on the top of the cap rather than the seal.
 
I bought a croft super micro. It arrived today and I totally love it.

Thanks for all the advice guys.
 
Hi, if you use phono, then the Exposure VII is supposed to have an excellent phono section.
I recently sold one for £205 so could be in budget , if you can locate one.
 
I used a 303 with a passive preamp. supplied by a PFM member. It was very good. I used a Pro-Ject phono box for the turntable.
I had a desire to tidy up the kit, which had many wires and mains leads, so I bought an early bronze cased Quad 34. I don't miss the passive, the phono stage is good and my little Harbeth P3ESRs sound lovely with the combination.
Aesthetically, the Quad looks right and timeless much like an original Austin Mini
British hi fi which works, looks good and gives much pleasure. What more could anyone want ? Incidentally, the passive and the the phono box almost covered the cost of the 34.
 
How do the 303's compare with more modern offerings? I have a 33/303 bought from a nice chap on here. It's lovely but I think most of the caps in both are original (33 has a service sticker inside from 1977!) so it's hard to judge their sound quality without a service / recap etc.

I'm very happy with the Exposure amp in our main system (with an LP12) but in the long term I do have a hankering to replace it with something a bit more classic. Maybe even try something like the 303 dual mono bi-amp setup mentioned earlier in the thread - I know it sounds tarty but I absolutely love the style of the old Quads...
 
How do the 303's compare with more modern offerings? I have a 33/303 bought from a nice chap on here. It's lovely but I think most of the caps in both are original (33 has a service sticker inside from 1977!) so it's hard to judge their sound quality without a service / recap etc.

Quite different IME. I actually prefer to view the 303 as kind of a 15 watt tube amp substitute as a) it just doesn't sound like a modern solid state amp, and b) that's the context in which it seems to give it's best performance. Like a typical tube amp it just doesn't like driving reactive loads below 8 Ohms at all and as such what you make of it all depends on what you want to do with it. Partner it with efficient and easy to drive vintage speakers, the Quad ESLs it was designed to drive, or modern tube-friendly speakers and it's something rather special IMO.

There is something very 'right' about the 303's mid-band and it gets out of the way in a way few amps do. I'd say it was mid-centric in presentation, the top is never dominant or strident, maybe recessed a little, though very nice and clean. It's anything but a bright and tizzy sounding amp. Don't expect it to have the dynamic slam or thump of a high power modern solid state amp either, this is a more gentle and laid-back presentation, but that's it's strength as it's not hyped-up or exaggerated in any way. It just lets music through in a natural and easy way. This is not stunt-hi-fi, it doesn't shout 'look at me' at all.

The contrast between the 303 and the later 306 is interesting: they are very different and I honestly couldn't tell you which I preferred as it depends on what speakers used. At present I prefer the 306 with my Tannoys and JR149s, the 303 with both pairs of Klipsch. Both are really nice amps and do work in the other context perfectly well, but they are sufficiently different to form a firm preference.
 


advertisement


Back
Top