Quad current dumping amplifiers
- Thread starter johnfromnorwich
- Start date
Difference with valves? It gives a lovely midrange, even with box speakers. Things just seemed right. Then I got the ESLs and they have a midrange to die for so everything just works. Not tried the 405 with my present Quads but it will be OK. A tweaked up 303 *might* be better, but hang on. Set the clock back to 1978ish. Quad's flagship speaker at that time is the 57. Most owners run the 303 with them. Then Quad launch the new all singing and dancing power amp, design award etc. Does anyone *really* thinbk it's going to be worse than the 303 on the same manufacturer's flagship speakers?
Quad will service a 405 at very modest cost. Budget £80-100.
Quad will service a 405 at very modest cost. Budget £80-100.
Tony L
Administrator
The Quad attitude was that all correctly designed amps sound identical, and that Quad designed amps correctly. IIRC they claimed the II, 303 and 405 all sounded identical as distortion upstream in the source or downstream in the speakers was orders of magnitude greater. I'm not in that camp, I can certainly hear differences between amps, though I've never directly compared any Quad amps - the only one I've ever owned is the 303 (the first in 1978, the second now).
Tony.
Robert
Tapehead
If the OP is near London and wants to try/borrow a servicecd 405/2 I'm happy to help.
I'm also happy to service a 405 with fresh caps on the boards and PSU for the cost of parts.
There are certainly important spec differences between the II, 303 and 405 and while I think these would give a minimal difference into a high impedance load, they should be audible into many modern low impedance speakers.
Back in the old days where 16 ohm loads were common and designs rarely fell below 8 I can see why the distortion spec alone would largely determine quality.
When driving difficult loads there are more factors to consider such as the stiffness of the PSU and output impedance and these become more important.
So I think Quad were right in their claims - for the period.
The big question would be can someone tell the difference betwwen say a Quad 606, Naim NAP250 and say a Cyrus power amp today. That gets interesting as I'd put good money on listeners being unable to reliably tell them appart unsighted. If the 405/2 wasn't clipping I'd add that to the list.
It must surely all boil down to audibility and importance.
If you have to sit and repeatedly go back and forth to determine a small difference then I'd argue it can and should be ignored.
I'm also happy to service a 405 with fresh caps on the boards and PSU for the cost of parts.
There are certainly important spec differences between the II, 303 and 405 and while I think these would give a minimal difference into a high impedance load, they should be audible into many modern low impedance speakers.
Back in the old days where 16 ohm loads were common and designs rarely fell below 8 I can see why the distortion spec alone would largely determine quality.
When driving difficult loads there are more factors to consider such as the stiffness of the PSU and output impedance and these become more important.
So I think Quad were right in their claims - for the period.
The big question would be can someone tell the difference betwwen say a Quad 606, Naim NAP250 and say a Cyrus power amp today. That gets interesting as I'd put good money on listeners being unable to reliably tell them appart unsighted. If the 405/2 wasn't clipping I'd add that to the list.
It must surely all boil down to audibility and importance.
If you have to sit and repeatedly go back and forth to determine a small difference then I'd argue it can and should be ignored.
johnfromnorwich
even my wife noticed the dif..
That's a very generous offer. Unfortunately, I'm in North wales (not near anywhere) and although I will be in London in a week or so, I'll be relying on public transport - so probably not practical. Given the kind of money these go for, I may just chance my arm and sell on if I don't like it. I've got a spare pair of Tannoy HPD/Lancasters that really ought to be sold so I can probably hide the cost and free up some floor space at the same time.
Robert
Tapehead
No problem.
They are quite small amplifiers (though weighty) so you are welcome to take it for a couple of weeks.
If you do buy one (mk1 or mk2) I'm happy to recap and test it for you.
Main cost is the two large PSU caps at around £25-30 the pair. There are a handful of smaller caps on the boards but those aren't expensive and I'll probably have some as they tend to come in packs of 5 or 10 minimum.
regards,
They are quite small amplifiers (though weighty) so you are welcome to take it for a couple of weeks.
If you do buy one (mk1 or mk2) I'm happy to recap and test it for you.
Main cost is the two large PSU caps at around £25-30 the pair. There are a handful of smaller caps on the boards but those aren't expensive and I'll probably have some as they tend to come in packs of 5 or 10 minimum.
regards,
John, a 405 is small enough to carry under your arm (even in the box) so take up Robert's offer if you can - especially as his amp will be in known "recently serviced" state.
Having had both 303 and 405-2 - and treated them cruelly (especially the 303) by driving 4 ohm Maggies - the 303 is still the one remembered fondly - to me its shortcomings are easy to forgive. The Net Audio PSU board (and to a lesser extent the SOA mods) made a giant difference to the way it coped with the Maggies.
Other than with ESL57s I'd expect the 405-2 to be objectively better (I think I've read that the famous Quad II vs 303 vs 405 test was with a 405 mk1) and much more of an all-rounder.
Having had both 303 and 405-2 - and treated them cruelly (especially the 303) by driving 4 ohm Maggies - the 303 is still the one remembered fondly - to me its shortcomings are easy to forgive. The Net Audio PSU board (and to a lesser extent the SOA mods) made a giant difference to the way it coped with the Maggies.
Other than with ESL57s I'd expect the 405-2 to be objectively better (I think I've read that the famous Quad II vs 303 vs 405 test was with a 405 mk1) and much more of an all-rounder.
Sorry, not to jump on the thread but i put out a WTD: for a 405-2 so if you did buy and was not happy i would consider taking it off your hands? you wouldnt find a problem shifting Quad amps as they sell relatively cheap, they are quick turn arounds.
Hi Robert hope all is well, thanks again for the 306 service. Not selling your 405-2 are you - i need a bit more power........?
Hi Robert hope all is well, thanks again for the 306 service. Not selling your 405-2 are you - i need a bit more power........?
Robert
Tapehead
Hi, hope the 306 is still working well
Afraid I need my 405/2 as it comes in handy for using/demonstating the Kensai speakers and they need a little more grunt than a 306 can manage.
regards,
johnfromnorwich
even my wife noticed the dif..
Another question. I've seen a few 405 and 405-2 with RCA inputs. Some admit to being retrofits, others don't specify. Was this ever a factory fit or will it always be a user mod?
Robert
Tapehead
Are these any good Robert?
I'll have a look tonight as the server at work is blocking the images.
The psu caps are 10000uf/63v. I am in the process of rehabilitating a early 405. I must say that I was in the same boat as the original post. I also own a pair of Quad II, which are my amps of choice though I was looking for a amp I could leave on for hrs and not worry about.I also use a Quad 303 though I was looking for a bit more power. I recently picked up a early 405 #19++++( has the lighter color heat sink) for $100 all original. I just replaced the signal caps and opamps(burr brown opa604ap) as well as psu caps. The last thing I have to do is reduce input gain. I have them driving a pair of Vandersteens and I must say the sound very good ! It has a bit more punch and bottom than the 303 though still very similiar in sound. I have had a 405-2 some 5yrs ago(fully serviced) and did not notice any diffirence between the two.
Paul R
pfm Member
Coincidentally I just opened the Jult 1978 Wireless World and read a feature by James Moir titled 'Valves versus Transistors' which reports on a Quad commissioned listening test comparing the 11, 303 and 405. The speakers used were Yamaha NS1000 and the source a Studer A80 running at 15ips.
I'll try and post scans somewhere soon.
You can guess the outcome though.
Paul
johnfromnorwich
even my wife noticed the dif..
Interested in reading that! Although I assume no difference was detected?
rhgbristol
pfm Member
Yes - agree with other posts - I've had a 405/2 for many years - driving originally ESL63s, then 989s and latterly in my second system Musical fidelity MC4s.
It is a bullet proof design, very easy to repair and work on, and is fully supported by Quad who will service whilst you wait if you take a trip to Huntingdon.
You will get a lot more sound for your pound than the equivalent from Naim.
Cheap as chips - tatty ones go for about £80-100, tidy later ones go for £200-250.
They were made between 1976 and 1993. The last ones have grey casing and phono inputs. Earlier ones are champagne finish with 4 pin din input.
I've happily used mine with lots of different pre-amps and it is not a fussy amplifier to drive.
Fully recommended
Richard
It is a bullet proof design, very easy to repair and work on, and is fully supported by Quad who will service whilst you wait if you take a trip to Huntingdon.
You will get a lot more sound for your pound than the equivalent from Naim.
Cheap as chips - tatty ones go for about £80-100, tidy later ones go for £200-250.
They were made between 1976 and 1993. The last ones have grey casing and phono inputs. Earlier ones are champagne finish with 4 pin din input.
I've happily used mine with lots of different pre-amps and it is not a fussy amplifier to drive.
Fully recommended
Richard
Robert
Tapehead
I can but don't need to guess Paul.
As you might suspect, I have the magazine article
Never compared a Quad II to anything but even I would have difficulty accepting that it sounds indistinguishable from a 405, so i think the easy load must be key.
Either that or the differences produced were simply not that obvious and therefore not material.
Over the past few years I've gradually revised where I draw the line in audio between real differences that matter and trivia.
Makes life incredibly easy in many ways since my choice of amp comes down to 'has it got the right sockets and can it drive the load I'm connecting' - and that's it really!