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DSJR
22-09-2010, 11:52
Sorry for the thread title, but after many months sitting upstairs collecting dust, I've brought the "Crofted" Quad II's down and plumbed them in..

http://i132.photobucket.com/albums/q8/DSJR_photos/QuadIIsSept2010.jpg

The bridged Crown D-60's do have a sense of "rightness" to them and they'll stay as a reference for a considerable time, but there was a feeling of "charm" with the updated 303 I bought recently. The 303 does have a certain anonimity in my setup though - perhaps that's a compliment, I don't know.

The II's though are something else. I can see the guys on HDD forum curling up imagining the distortion, high output impedance and all sorts of other things where these amps from 1962 are concerned, but do you know, I don't give a flying fig what they think. The sound is so inviting, yes, lush too without much bass "weight," and even with the Spendors, there's this ability to put a huge grin on ones face, despite the amps not being anything the last word in clarity. CD's sound lovely with no nasties at all and as for the Decca... :laugh:

I played SEAL II just now and although the slam and sheer physicality of the mixes when played through my old ATC100A's was missing, there was texture and "air" from the BC2's I didn't think them capable of.

Perhaps this is one thing about old and inexpensive systems that can work so well. We don't expect much from them and are pleasantly surprised when they transcend out pre-conceived ideas.

"Strokes of Genius?" Too bloomin' right IMO... :king:

Rare Bird
22-09-2010, 12:50
Must get some Net 303.3 boards, been going to for a year now..

Marco
22-09-2010, 15:56
Nice one, Dave. I'm glad to hear that the old Quad IIs are hitting the spot :)

I see they have the original GEC valves, too. Those alone are worth a fortune! Apparently the John Howes modified Quad IIs are something else - have you heard those?

Even without taking things to that extreme, I bet there is some judicious 'tweakage' that could be done to yours in terms of updating/upgrading key components, like caps, etc.

Have you done any mods to them or are they totally original?


I can see the guys on HDD forum curling up imagining the distortion, high output impedance and all sorts of other things where these amps from 1962 are concerned, but do you know, I don't give a flying fig what they think.


Good on you....

I care much less than that about what they 'think' - idiots, the lot of them! :wanker:

Marco.

spendorman
22-09-2010, 16:06
I always liked the sound of Quad IIs. What impedance tapping on the output transformers are you using?

http://farm5.static.flickr.com/4151/5015174172_75fcba48fd_z.jpg

Thermionic
22-09-2010, 16:46
Good to see your Quad IIs and happy to hear that you like them. I bought a pair 2nd hand in 1969 and have used them almost continuously ever since, and they always sounded good (at least on straight ahead Jazz and classical). About 10 years ago I replaced ‘the usual suspects’ and installed phono sockets and binding posts etc. Bass can be improved I recall by increasing the value of the cathode bypass cap (which often dries up anyway), they are also on (mostly) original valves.

I use them with a pair of ELS57s (naturally).

hifi_dave
22-09-2010, 16:47
Fat, dull, sluggish, flabby no balls.....:eyebrows:


The Quad 11's are none of the above and partnered with the 'right' speaker, they can sound stunning.

Those Quad's sounded pretty fine into my Harbeth M40.1's as I recall...:cool:

DSJR
22-09-2010, 18:38
He's back too :)

Marco, you have a lot going on in your life, so probably have forgotten this pic which I'm sure is on here somewhere...

http://i132.photobucket.com/albums/q8/DSJR_photos/QuadIIcropped.jpg

What's been done by Glenn here may well de-value these to purists, but the valve power supply actually reduces the output to 12W or so, while supposedly increasing stability. All the resistors were replaced with 1% types and I believe that film caps of various types were used in the business end, a standard electrolytic being used in the supply side.

These mods were done nearly twenty years ago now (yikes!!!!!) and I should add that these amps would have been on the scrap heap had they not gone to Glenn for a fettling. I know there's more that can be done, but these are far enough removed from the Quad original as it is.

Marco
22-09-2010, 19:12
Ah, nice one, Dave - I haven't seen that pic before... Oi loikes! :cool:

Marco.

DSJR
23-09-2010, 10:25
I always liked the sound of Quad IIs. What impedance tapping on the output transformers are you using?

http://farm5.static.flickr.com/4151/5015174172_75fcba48fd_z.jpg

Sorry, missed this one. is that lot yours?

To the best of my knowledge, the tappings are set to 8 Ohms. The taps are set underneath the caps and power supply and I only glanced in that direction. To be honest, I don't feel like fiddling and as the Spendors tend to have a high impedance apart from very high frequencies, I'm not sure i should change things. I can't for the life of me remember what tappings I used for the Radford STA25 and BC1's I owned thirty odd years ago, but I believe I worked on the assumption that valve amps didn't like being open circuit but could tolerate a short (better than a solid state amp) so may have stayed with the 8 Ohm taps...

spendorman
23-09-2010, 10:34
That pic is very old. Stupidly, I sold two sets of the II/22 many years ago, leaving me with one very good set. Most the other stuff that one can see (plus a lot more) is still here.

I can't remember properly, but I think that it is said that one of the output tappings is compromised on the Quad II.

DSJR
23-09-2010, 11:42
I don't think I ever played around with these to find out ;)

I wish I had some Epos ES14's at the moment. The II's LOVED them and my recovering ears could do with a bit more "fizz and glare" right now..... The sound today is supremely harmonious but sooooooo safe.

spendorman
23-09-2010, 12:09
Quoted from:

http://www.turneraudio.com.au/quad2powerampmods.htm

"My view is that Quad II amps should NEVER be used on their 16 ohm outlet match, even with ESL57 connected, and that means using the 8 ohm OPT configuration even though that unfortunately results in winding losses of around 17%. There is also a way of making a 4 ohm configuration, by taking the output from the point Q on the OPT but the windings from Q to T cannot then be used at all and leakage inductance and winding losses dramatically increase for fairly poor performance.
In order not to confuse people with the complexity of wasteless transformer impedance matching, Peter Walker settled for the simpler method of a maximum of just two OPT links for 8 ohm, and one for 16 ohms, and the load adaptability of Quad II was forever compromised.
Despite the high winding losses with 8 ohm configuration, the amps work OK, although they become
only conditionally stable, instead of unconditionally stable"

DSJR
23-09-2010, 13:28
Thank you paul for finding that quote.

I think the II's I have invert absolute phase. I know some don't mind or care about such things, but the BC2's, for good or ill, are very sensitive to it. I reversed the speaker connections at the amps and thought/imagined the sound was a bit more "immediate." I'll keep with it for a few days in the hope things will improve as my ears become less blocked..