I was hoping to see a preset potentiometer that had been inserted between the rear of the input socket and the destination circuit board.
The 2.2 kiloohm resistors on the speaker outputs would appear to be a later addition.
I'm afraid that figuring out how the previous owner set up the system requires a hands-on approach that I am not in a position to supply.
The 2.2 kiloohm resistors on the speaker outputs would appear to be a later addition.
I'm afraid that figuring out how the previous owner set up the system requires a hands-on approach that I am not in a position to supply.
This is not correct. Each board has current limiting. Removing one will have no effect on the other’s maximum current whatsoever.
It’s curious that Rob Holt posted that misinformation in post #20 when it had already been contradicted in a quote from Joost Plugge in post #16.
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They appear in the schematic and were fitted at the factory.
This is a spare amplifier board for the 33.
I don’t see any evidence of monoblocing here.
The pictures of the second 303 don't reveal any useful information other than it appears to be unmodified.
I would be checking that each 303 works individually with the 33 in the manner that Quad originally intended.
Only then would I be considering the possibility of converting each 303 to a monoblock.
You'll be aware that, when testing vintage equipment, it is advisable to use a dim bulb tester and disposable speakers.
I would be checking that each 303 works individually with the 33 in the manner that Quad originally intended.
Only then would I be considering the possibility of converting each 303 to a monoblock.
You'll be aware that, when testing vintage equipment, it is advisable to use a dim bulb tester and disposable speakers.
Regarding the new speakers thay are mordant short ms235 but with the ms400 midrange which is 50mm soft dome. My transmission line speakers (I have 2) need the super tweeter. The dome midrange and super tweeter I was thinking about using them separately with their crossover and the transmission line used for bass and mid (b110)
But that's another thread
But that's another thread
So.
I have checked each of the quads individually and everything works. The cable that is split into 2 ways after the 33 is interesting. Looking at it the original owner has for 1 quad 303 connected only left and right for the other. I hope pictures can explain better
I have checked each of the quads individually and everything works. The cable that is split into 2 ways after the 33 is interesting. Looking at it the original owner has for 1 quad 303 connected only left and right for the other. I hope pictures can explain better
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It would certainly appear so. Perhaps the previous owner was simply out to impress his pals with the visual appearance of his system!
I'd be inclined to use the 33 preamplifier with just one of the 303 power amplifiers and keep the other 303 as a spare.
I'd obviously have to construct the stereo wired DIN cable required to connect the 33 to the single 303.
Alternatively, I'd consider running the system exactly in the way the previous owner did - just for the cool factor! 😎
Thanks, I have the single cable to use. 4pin to 4pin but I don't get it....to go through all that time soldering and gluing for what?!
Only then would I be considering the possibility of converting each 303 to a monoblock.
Any advice on how to mono block the amplifiers?
Any advice on how to mono block the amplifiers?
The original owner may have expected, and even obtained, an audible improvement. You could try his method and decide for yourself.
The applicable advice is in the Quad PDF that you presented earlier.
You would use the first method "Parallel Connection 90W - 4Ω" involving the addition of a 5 kiloohm pre-set linear potentiometer.
The initial adjustment stage and how to connect the speaker when in operation are clearly described in the text.
If you don't feel confident about following those instructions then I strongly suggest you do not attempt this modification.
More to the point: This modification is only worth doing if your speaker is 4 ohm and you require more power to be developed into that load.