Could the fact that the preamp has too much gain the reason I am hearing hash/static through the loudspeakers even when the volume is turned right down?
Would attenuators address this as well ?
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Could the fact that the preamp has too much gain the reason I am hearing hash/static through the loudspeakers even when the volume is turned right down?
Would attenuators address this as well ?
Yes and yes :)
Thanks for the reply Alan, appreciated. Like the Preamp; shame it's not perfectQuote:
Originally Posted by Firebottle
Is it under warranty? If not it is probably a simple job to lower the gain.
Do you have a circuit diagram by any chance?
I would doubt very much whethere these two items have even been considered by quad to be a pairing, let alone been designed to work together.
Yes you could fiddle with the insides of one or other to get the gain to match but I'd personally look a bit futher for a pairing with more obvious matching in terms of gain/input sensitivity.
The Preamp is only on demo at the moment. Kindly lent to me by a dealer I've known and purchased items from since the 70's. He kindly obliged my curiosity to try a valve pre. The obvious is I guess is to buy the power amps that do match; but I'm not prepared to spend that sort of cash. I have to agree that Quad would probably not recommend this pairing and as much as I like it, the mismatch is unacceptable .
Anybody recommend a good preamp to front a Quad QSP ( I don,t need a phono input)
Thanks for all your replies guys
Back to the drawing board as they say
Sure quad would say the elite pre. have you tried a passive?
If only after a simple (no Phono) preamp.
A simple Passive comprising: a Pot , Buffer and an Autoformer is as Likely as good a "Preamp" as yet devised by Humans.
Really inexpensive to assemble .. adding insult to injury :eyebrows:
Hope you're well Tony?
The reason that the volume is a little hot may be that the input sensitivity of the power amp and output of the pre are probably not matched (designed to work together) and you probably do have too much gain from the pre. I believe that this amp uses about 15sB of gain from its single 6111WA valve per channel outputting at 1V . However S/N isn't great at >80dB so with sensitive loudspeakers and a more than typical 33dB gain on the power amp you may well hear some hiss/hum. 48dB of gain is quite a lot!
The main issue here for the "hot" volume though is that you can easily over loading the power amp input which only requires 760mV for a full 33dB gain through the power amp. The pre also has much poorer S/N ratio than the power. Personally, I would have matched the power with it's partnering preamp or a passive pre. The QC24 doesn't appear to be a good match. Yes, you can use attenuators or have someone modify the pre-amp circuit with some resistor value changes between the valve gain stage and volume pot but you're still left with pre that can't match the superior S/N of the power so it won't give you the quiet background of a better match especially with any other valves devices in the source or with vinyl sources. Tom's point is valid about the pairing.
If you like what it does, it's what you think that matters, so you could try it with some attenuation and try and get the output down. If it likes to see a load of 50KOhms, that indicates a relatively high oputput impedance from the pre so it may not be suited to driving long interconnects but if it doesn't appear to be rolling off the HF (ie forming a low pass filter) then, again, don't worry about it.
Bottom line: It isn't the best match but the gain can be addressed.
Hi Paul,
Hope you're well also.
Thanks for all the input guys; definitely gonna knock this one on the head. If I'm gonna spend that sort of money it needs to be
right and this is definitely a mismatch that I don't intend to try putting right. It was a worthwhile exercise; but it's going back to the dealer.
Do all valve preamps exhibit the same 50Kohm ish requirement of a power amp or is it just the Quad. You'll see from my profile that I do have the matching Elite SS preamp but I'm curious about alternatives, and now I don't require any phono input; in fact just a single input from a DAC is all that is required - What are your recommendations ?
The Quad valve pre did add some heft and body to the sound, integrated the bottom end quite nicely, or was the sound of overloading ?????