SS amp for Quad 63

[Firebottle]

ha, did you get that working alan?

Yes Grant I did, many thanks.

[struth]

Yes Grant I did, many thanks.

what was it? thought it might be a cap

[Stryder5]

OK Chris here is a left field suggestion, and not shabby in the slightest. Very much cheaper too, these are new amplifiers from excess stock.

I use one of these as a stereo PA into my '57s, only bettered by Oli's Neurochrome

https://www.ebay.co.uk/itm/Proart-mo...97.m4902.l9144

If you have a suitable preamp there is a 30 second mod to bridge the controls on the front and raise SQ further.

Apparently these were designed and used in jukeboxes.

Gary

[Barry]

I would suggest either a 606 or a British built 909. The rumours are true: Chinese-built 909s now use locally sourced components, which are decidedly inferior (especially the capacitors).


Although a bit off topic, there is some misunderstanding of the maximum power to which the Quad 57s can be subjected. In the Quad instruction booklet, on page 10 it states: "Other amplifiers if they are properly regulated (not more than 33 peak volts with any load) are unlikely to cause damage to the loudspeaker, although they may not neccessarily provide the correct performance because of the very strict stability requirements."

Now assuming the Quad 57s have a nominal impedance of 10 Ohm, 33V peak voltage swing implies a peak power of 108W, or a mean power of 54W. This is usually rounded down to 50W, hence the voltage limiter which when fitted to the Quad 405 amplifier reduces the voltage swing to 20V rms, or 40W into 10 Ohm.

When the Quad 57 was first introduced, the amplifier requirements were somewhat more specific. In particular, Quad stated: "With a 30 Ohm resistive load, the amplifier should at no time be capable of producing more than 35 peak volts across the loudspeaker terminals." There is good reason for this restriction; the Quad 57 has an impedance of around 30 Ohm at low frequencies, which thus involve the bass panels of the speaker. The stator to stator distance is 3.2mm, and the bass panels are fed through a 270:1 step-up transformer. Thus 35 x 270 = 9450V, or a maximum field strength of 9.45kV/3.2mm = 2.95kV/mm. The breakdown field stength of air is around 30kV/cm, and it is this that sets the maximum voltage swing.

[Opti-cal]

Thanks for the responses.

Good info there too Barry, very interesting.

Well I've pulled the trigger on the errr.... Proart's.

Couldn't resist after such a ringing endorsement. Hope you weren't all just pulling me leg!!

I'll also definitely look out for an early British 909 as they seem the "perfect" accompaniment to the 63's.

Power and control with a synergy born of design.

Will be trying these out on various speakers also just for fun.

[Stryder5]

Thanks for the responses.

Good info there too Barry, very interesting.

Well I've pulled the trigger on the errr.... Proart's.

Couldn't resist after such a ringing endorsement. Hope you weren't all just pulling me leg!!
M
I'll also definitely look out for an early British 909 as they seem the "perfect" accompaniment to the 63's.

Power and control with a synergy born of design.

Will be trying these out on various speakers also just for fun.

I've bought a pair too!

Gary

[struth]

The guy will be wondering what happened lol.

[Bigman80]

They are surprising. Just wait and see.

[struth]

They are surprising. Just wait and see.

Indeed.. Good amps. Proart make some expensive gear

[Opti-cal]

Indeed.. Good amps. Proart make some expensive gear

Are you Quad-amping Grant or just a bit lonely?!