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Why do vintage Quads work well with vintage Tannoys?

Seanm

pfm Member
I’m finding that a Quad 306 works very well with my Berkeley mk2, better than the more modern integrated that worked so well with the Harbeths that preceded them. This seems to mirror others’ experiences.

Why? I’ve heard that a relatively low damping factor might be involved, but it all seems a bit speculative, as information on this, and output impedance, seems to be unavailable.

I’m happy with the Quad overall, but I’d like to experiment with different pre amps, and with its high sensitivity and relatively low input impedance the Quad is a little limiting. Without knowing what the Quad’s doing right, however, I’ve no idea where to look for something that might do the same things without imposing the same restrictions. Any ideas?
 
I have the same amp and speakers here Sean. Tried multiple amps before spending the princely sum of £220 on a 306, which has seen off my other amps.

The only amps I see regularly mentioned as being superior to the 306 for vintage Tannoys are Radfords.

PS I use 20db attenuators with my 306. This allows an active pre to be used.
 
There's nothing vintage or old fashioned about a Quad 306! I assumed the thread would be about Quad II's...

It has a high damping factor of about 160.

There's nothing about it that would seem unusual or particularly suited to the speakers any more than 100's of other amplifiers.

There will be many amps which sound worse and many better... A 306 is spectacular VFM though!
 
I’m happy with the Quad overall, but I’d like to experiment with different pre amps, and with its high sensitivity and relatively low input impedance the Quad is a little limiting.

I’ve used a gain-reduced Croft 25R in the past and whilst that was still a bit hot for the Stereo 20 and Tannoys it was perfect with the 303, so that’s a really good preamp option if you want more character and ability to fine-tune than a stepped attenuator passive or TVC. Luckily my JC Verdier valve pre has five internal output settings and on its lowest it is fine with the 303 and Tannoys, the middle one is fine for LS3/5As etc, so it all works here. The 34 is a lot better than it gets any credit for too, the issues with the phono stage (a rumble-filter that sucks bass/slam and crazy high MM capacitance) can be fixed easy enough. The 306 is a little hotter than the 303 (I’ve owned both) but there are some options. It is also possible to alter the 306 input gain to 1V, which would make it much easier to match should you wish. Rob did it to his and I’m sure will tell you how. Just changing a few resistors I think. It is a very well laid out amp to work on - you can recap one in about 15 minutes!

PS Richard (Lordsummit) is using my old 306 straight on the variable output of his Chord Mojo and it sounds great. Single-source systems can be very simple indeed!
 
There will be many amps which sound worse and many better... A 306 is spectacular VFM though!

Which do you prefer, Jez, Quad 306 or Cambridge A 60?

For my part I think the 306 is a devious amp. When you first hear it you think this is fine, really fun and good, fast and punchy. There’s a huge amount to enjoy there. And then, the more you hear it the more you realise that it really doesn’t present the higher level partials of acoustic instruments well, it’s not a timbre amp at all. I asked that question about A 60 because something I heard makes me wonder whether it’s actually a better amp, better at timbre and enough PRAT.

Cheap Rotels are even cheaper than 306s, and they’re a similar sort of thing I think. What you prefer is largely down to presentation.

I have a 306 and intend to hold on to it, but that’s because it’s light, small, easy to store, well built and, given the value on the second hand market, not worth the trouble of selling it.
 
I've also been finding it interesting to compare the different needs of Tannoys and Harbeths. For example with my Eatons I was using a powerful hybrid power amp - Unison Research Unico DM, which is the same amp I used (amongst others) with Harbeths and with ESL 63s. It was spectacular with the Quads and very hard to beat with the Harbeths - only really bettered by a VTL ST150, and even then not in every way. However I recently bought a Unison Research Triode 25. This sounds a bit woolley with the Harbeths, with accentuated sibilance and a quite diffuse sound - luxurious in some ways, but the sort of match that would confirm some listener's unfounded prejudices about valve amps, or about Harbeths, or both! (Although I've heard some dealers praise the combination). But it's just superb with Tannoys. Far better than you'd imagine for a modest integrated. And better than several other well respected valve integrateds I've tried.

Like Sean, I'm not sure why this is the case. However I can tell from the negative feedback settings that this definitely has an important effect. I wonder how much that is a factor?

Another factor with the Triode 25 is that it avoids the usual 4 and 8 Ohm taps (which so often results in annoying indecision), with just the one 6 Ohm setting.
 
Cheers all. Especially interesting to hear from Jez about the unexceptional damping factor and the fact that the 306 isn’t doing anything remarkable other than being good.

I will swap my exposure back in and see what’s what. When I first got the speakers I thought they sounded too lean with the Exposure and that my 34/306 was much better. But this was sort of what I expected from reading others’ accounts, so...
 
For my part I think the 306 is a devious amp. When you first hear it you think this is fine, really fun and good, fast and punchy. There’s a huge amount to enjoy there. And then, the more you hear it the more you realise that it really doesn’t present the higher level partials of acoustic instruments well, it’s not a timbre amp at all.

I don’t agree. The 306, like all Quads, isn’t a hyped-up amp at all, but to my ears the detail is there. I’ve heard it driving ESLs and 63s and if any speaker is going to highlight poor or unnatural timbre it is those. It just doesn’t bleach or spotlight the top the way some ‘dealer dem winner’ amps do, but that is why I like Quad power amps. They just get out of the way and draw no attention beyond the music. The 306 is a stunningly good amp IMO and an almost comical bargain given how competent and simple to service it is. One of hi-fi’s real bargains and from what I’ve heard I definitely prefer it to either 405 version. Just more open and alive somehow, though I’ve never needed 100W for anything.

PS FWIW I personally prefer the 303 to the 306 as it seems such a balanced partner to the sort of speakers I like (Tannoys, JR149s, LS3/5As, ESLs etc), all of which lie in the 8-16 Ohm range the 303 was designed for. Subjectively I hear the 303 (in this precise context) as sounding bigger, more spacious and weightier, though move away from this particular class of speaker and the 306 just kills it. I spent a very long time listening deciding whether to keep a 303 & 306, or two 303s. I ended up with the latter as I can’t see myself changing speaker type again. The only thing on my radar is maybe adding a pair of original ESLs somewhere at some point, which obviously the 303 was designed to drive.
 
I don’t agree. The 306, like all Quads, isn’t a hyped-up amp at all, but to my ears the detail is there. I’ve heard it driving ESLs and 63s and if any speaker is going to highlight poor or unnatural timbre it is those. It just doesn’t bleach or spotlight the top the way some ‘dealer dem winner’ amps do, but that is why I like Quad power amps. They just get out of the way and draw no attention beyond the music. The 306 is a stunningly good amp IMO and an almost comical bargain given how competent and simple to service it is. One of hi-fi’s real bargains and from what I’ve heard I definitely prefer it to either 405 version. Just more open and alive somehow, though I’ve never needed 100W for anything.

PS FWIW I personally prefer the 303 to the 306 as it seems such a balanced partner to the sort of speakers I like (Tannoys, JR149s, LS3/5As, ESLs etc), all of which lie in the 8-16 Ohm range the 303 was designed for. Subjectively I hear the 303 (in this precise context) as sounding bigger, more spacious and weightier, though move away from this particular class of speaker and the 306 just kills it. I spent a very long time listening deciding whether to keep a 303 & 306, or two 303s. I ended up with the latter as I can’t see myself changing speaker type again. The only thing on my radar is maybe adding a pair of original ESLs somewhere at some point, which obviously the 303 was designed to drive.
It’s this kind of talk that makes me want to hear the 303, although I wonder if it will suit the later drivers of the Berkeley IIs as well as it does your Golds.
 
It’s this kind of talk that makes me want to hear the 303, although I wonder if it will suit the later drivers of the Berkeley IIs as well as it does your Golds.

No idea, I’ve never tried it. By the time the HPDs were well established most studios etc seemed to have moved onto the 405 to drive them, so you may well be exactly where you need to be with the 306. I’ve always viewed Tannoys in the context of their era, e.g. Reds and before are clearly valve-era, HPDs and later were solid-state era, and the Gold is the pivot-point between the two. I’d be reluctant to change the 306, assuming it is serviced and working exactly as it should I’d think long and hard about preamps. I personally seem to like valve ones, but there are many options worth exploring, and the input sensitivity isn’t fixed in stone, it can certainly be altered without butchery.
 
Yes I'd like to hear a good 303 again. The problem is that Tony's 303 has been modified and those modifications may be making a difference -- not to mention the fact that he's playing it through some incredibly rare valve pre amp.

My comments about the 306 came about through a recent experience, where I had it playing with my Spendors for a couple of weeks -- and I listened a lot. As I say, I was impressed at first, I nearly posted something here to say how wonderful an amp it is. And it is wonderful! But after a week or so I realised that the timbre of acoustic instruments was not as well caught as with the Krell, or the Radford or the Conrad Johnson.
 
No idea, I’ve never tried it. By the time the HPDs were well established most studios etc seemed to have moved onto the 405 to drive them, so you may well be exactly where you need to be with the 306. I’ve always viewed Tannoys in the context of their era, e.g. Reds and before are clearly valve-era, HPDs and later were solid-state era, and the Gold is the pivot-point between the two. I’d be reluctant to change the 306, assuming it is serviced and working exactly as it should I’d think long and hard about preamps. I personally seem to like valve ones, but there are many options worth exploring, and the input sensitivity isn’t fixed in stone, it can certainly be altered without butchery.
Yes, probably all I need, although one of the things that’s prompting me to look around is the fact that it needs serviced but is in such poor cosmetic shape I’m reluctant to throw money at it. The other thing is input impedance, more than sensitivity really: whenever I identify an interesting looking valve pre it turns out the output impedance is a fair bit higher than would suit the Quad.
 
Yes I'd like to hear a good 303 again. The problem is that Tony's 303 has been modified and those modifications may be making a difference -- not to mention the fact that he's playing it through some incredibly rare valve pre amp.

My comments about the 306 came about through a recent experience, where I had it playing with my Spendors for a couple of weeks -- and I listened a lot. As I say, I was impressed at first, I nearly posted something here to say how wonderful an amp it is. And it is wonderful! But after a week or so I realised that the timbre of acoustic instruments was not as well caught as with the Krell, or the Radford or the Conrad Johnson.
Aren’t they all pretty special though, and expensive? But it fits my experience with Harbeth: the Exposure really was quite a lot better with those.
 
Aren’t they all pretty special though, and expensive? .

Yes, but you're pretty special, and expensive. You deserve it!

(Seriously, as I said the 306 is a wonderful amp. But I'm curious about the A60, given the comments from someone who serviced the CJ)
 
Yes I'd like to hear a good 303 again. The problem is that Tony's 303 has been modified and those modifications may be making a difference -- not to mention the fact that he's playing it through some incredibly rare valve pre amp.

I’ve got two. One I fully rebuilt with after-market Dada boards etc as it had suffered some burn-out in its past and the original boards were not in great condition even after a trip to Quad. This amp was effectively free (came with my Tannoy haul) so I didn’t object to sinking some money into it. My other one was previously owned by @John_73 and he did an amazing restoration rebuild on it so it has all the original carbon resistors, transistors etc, the only changes are larger coupling caps and slightly larger PSU caps. The latter amp is the better sounding of the two, it has more heft/kick to it and a beautiful open spacious mid, the Dada sounds more ‘modern hi-fi’, smaller, and a bit lacking in grunt. I need to revisit the Dada one at some point (it is actually doing great work in the TV system) as it does have smaller output caps than the other one so I may swap some bigger ones in and see if that closes the gap between them.

The Verdier preamp is a big part of my main system sound. I have it stuffed with some very nice vintage Mullards and it is stereotypically ‘valve’ in having a big warm, weighty open and spacious sound. I love it, but I accept it isn’t neutral and some will hate it. It has a very nice MM phono stage (the inbuilt MC step-ups are less successful and hum a bit IME). I can’t see my ever swapping it out as it works so well with the 303. I’ll likely retire with that combo into the LS3/5As or 149s if I end up somewhere that can’t take the huge Tannoys. The other (Dada) 303 has a Audio Synthesis stepped attenuator passive pre, and that works great too, though I do personally prefer the bigger, punchier sound of the valve pre. The recapped and lightly tweaked 34 is surprisingly good too. I need to dig that out and give it a run soon as it’s been sitting in its box for a long while now and electronics is always best run now and again to keep the caps formed etc.
 
I for one tried the A60 on my ESL’s against the 306, the 303 and the 405 (I have them all).
Not up to the job.
The best is the 303 here no contest. The 306 is pretty good too. The 405 was least preferred.
It might be very different on Tannoys. On my 95 dB Cabasses, the three amps sound about the same I find.
 
Just to add that I briefly owned a 306 too, and was very impressed with what it was capable of especially considering its comparatively diminutive dimensions. Only sold it on as I already have a 606. Couldn’t tell an audible difference between the two, which shows what a bargain the 306 is. Love the aesthetics too.
 
Cheers all. Especially interesting to hear from Jez about the unexceptional damping factor and the fact that the 306 isn’t doing anything remarkable other than being good.

I will swap my exposure back in and see what’s what. When I first got the speakers I thought they sounded too lean with the Exposure and that my 34/306 was much better. But this was sort of what I expected from reading others’ accounts, so...

160 is a high damping factor! If damping factor (output impedance really) bothers you then figures between around 4 and 16 are "where the action is" as far as interaction with speakers causing any "sound signature" goes. Only the Quad II is that low overall with the 303 being next but a rather odd output impedance in as much as it is capacitor coupled but a smallish cap and feedback from before the cap so damping factor prob about 30-40 or more at a few hundred Hz upwards but getting less and less as frequency goes down and is about only 4 by 30Hz
 
160 is a high damping factor! If damping factor (output impedance really) bothers you then figures between around 4 and 16 are "where the action is" as far as interaction with speakers causing any "sound signature" goes. Only the Quad II is that low overall with the 303 being next but a rather odd output impedance in as much as it is capacitor coupled but a smallish cap and feedback from before the cap so damping factor prob about 30-40 or more at a few hundred Hz upwards but getting less and less as frequency goes down and is about only 4 by 30Hz
Thanks Jez - I meant unexceptional in that it's high, like most modern SS amps. If I have this right. Forum searches have encouraged me to believe that Tannoys can work better with higher impedance/lower DF amps.
 
Which do you prefer, Jez, Quad 306 or Cambridge A 60?

For my part I think the 306 is a devious amp. When you first hear it you think this is fine, really fun and good, fast and punchy. There’s a huge amount to enjoy there. And then, the more you hear it the more you realise that it really doesn’t present the higher level partials of acoustic instruments well, it’s not a timbre amp at all. I asked that question about A 60 because something I heard makes me wonder whether it’s actually a better amp, better at timbre and enough PRAT.

Cheap Rotels are even cheaper than 306s, and they’re a similar sort of thing I think. What you prefer is largely down to presentation.

I have a 306 and intend to hold on to it, but that’s because it’s light, small, easy to store, well built and, given the value on the second hand market, not worth the trouble of selling it.

An odd comparison! Quad 306 for me but it's a while since I heard either and I've never directly compared them.

Quad (all Quad amps) to me is a "Ronseal amp" .... does what it says on the tin! Well made, reliable, interesting quirky styling. Performance? I don't like the pre amps at all. Power amps? 303, 306, 405 and 405-2 etc... For what you will pay for a decently working second hand one (I'm thinking £140 - 200 ish for that range) they are good and excellent VFM but IMHO none of them is a "giant killer on the cheap". Compare with things like Rotel RB850 and 870 not with Krell, Radford etc!
If they were cars they'ed be Ford Mondeo 1.6L or similar. Gets you from A to B reliably and without drama and cheap to run etc.
 


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