Quad valve amp questions

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I have the opportunity to buy a pair of Quad II forty monoblocks with the matching preamp, the QC twentyfour for a good price.

I love design that has stood the test of time. For example I still shoot film on 50 year old Leica cameras. I have to say I am intrigued by the whole valve thing but have a few questions. Will they have enough power to drive my MA RX6s?. Do they need to be left on all the time to get the best out of them and if so are they power hungry when left on standby?

I mostly listen to classical (more solo instruments, choirs, chamber groups but some large scale symphonic works) and jazz. I don't need it loud enough to break windows and the room is an average size living room.

I will have an opportunity for a shop audition but am keen to get some pointers for life with valves before having a listen.

Thanks in advance,

David

 

[Anonymous]

yes ample power for the RX6, unless you really want to go loud. Should be a nice match for the MA which can sound a bit mettalic with some amps (but not with these). You can leave the Quad IIs on all the time - but its perfectly fine to switch them off when not in use. When re-activating, power-up the source first, then turn on the Quad IIs. Let them warm up (probably about 15 min) before pressing play on the source. Enjoy these wonderful amps.

 

[Anonymous]

Cant comment on the Ma's but they drive my Sterlings with more than enough Ooomph.

Leave on all the time...absolutely not. The valves have a finite lifespan (recommended operating life) somewhere around 6000 hrs and leaving them powered up even without a signal going thriugh them will count against their lifespan. There is no standby switch on the 40's so they are either full on or off. Some valve amps have them but the 40's doesnt.

Initial warmup of 15 min and dont switch them back on until at leat 30 minutes have passed since they were switched off.

HTH.....

 

[Anonymous]

Thank you Kevin & Ray.

Ray, please excuse my ignorance but what bad things will happen if I turn the amp back on before the valves have cooled down?

I'm still a little worried about the power consumption thing. Valves don't seem to have great green cred

I suppose if I switch them off when not in use, they will use exactly zero power and I could save on the gas bill for heating in winter

 

[Anonymous]

Turning back on before properly cooled down will cause the valves to 'strip'. as will using them before properly warmed up.This will shorten the life of the valve. The concept is difficult to explain but easy to understand so if you do an internet search you will find out what valve stripping is all about. Basically its the stripping of the coating/material on the valve cathode.

Power consumption isnt that high (180 VA max) ...not really much more than for a tranny amp of that size...but you do have 2 of them.

They do get lovely and warm so be careful where you place them. The transformers get surprisingly warm as well.Best advice is to remove the guards unless you have small kids around. This helps with cooling and you will also get to see the glow of the valves. Another thing worth of note is they are heavy...~16Kg each. Good supports needed.

The link below will tell you all you need to know

Quad manual

 

[Anonymous]

Ray you are a mine of information. Thanks for the link.

I do have children however they are just old enough to know what not to touch. Whenever I have the grills off my speakers, my four year old points at the cones and says "don't touch"

The top shelf of my rack should be up to the job.

Oh and are they any good?

If I get these, all I would need is a pair of ESL63s, the LP12 and the pipe and the slippers and I would be set for life.

Can't wait to audition.

 

[Anonymous]

Any good...I should coco. Just make sure they are warmed up before you go for audition.

Does the QC24 have a phono stage in...check because its an option that may not have been fitted. It will have the phono button but its a line level input until the phono board is fitted.

Good luck and let us know how you get on...