Quad 33/303 developed a problem

[dantheman91]

Hi

Not sure where to put this so here goes

noticed the last couple of days that my quad is only playing in mono not stereo in there any thing i can do i have spayed the balance switch etc and checked the din leads. any sujestions on what else i can do.?

Thanks
Dan

[DSJR]

The "stereo" switch must be pushed in (tbh, the thing won't play if this or the mono buttons are all out).

Since the switchbank on the 33 is mounted directly on the mother-board, it's unlikely to be a fault there.. The 303 is also two separate channels served by a common power supply, so unless the wiring behind the 4 pin socket is fouling and shorting the two channels together, it's unlikely to be there - probably......

Which leaves the interconnect wiring! Quad supplied what I would call "adequate" wiring and the later interconnects they provide use good inexpensive screened "fig8/shotgun" style cabling. Having said this, DIN plugs can be a pain IMO. If the cables get snagged, sometimes the insulation around the inner "hot" conductors can retract back enough to short together before the solder joint breaks. If you have Quad-original interconnects, this is frankly unlikely, but new and more up-to-date interconnects would be a good idea in any case..

EBay is a good source of cables, as indeed Quad themselves. I like the Van Damme cables for good inexpensive wire and "Soundstable" on eBay does a reasonably priced 5pin to 5 pin DIN. Rick is a great chap and I'm sure could give you a good quote for a similar 4 pin one wired properly for Quad (different to Naim wiring by the way...). Failing that, Flashback sales have a great reputation for quality DIN interconnects for under £30

[dantheman91]

Thanks so much for the info. the interconnects this could be true because the guy i bought it from made the interconnects himself so i will buy some new ones could it also be the din to din leads to connect the pre to the power? i only use to din leads one for cd and one for Vinyl.

i have the stereo button pushed in and the 2 mono puttons are out


Thanks
Dan

[DSJR]

See if you can CAREFULLY prise open the DIN plugs and check the wiring. If you're getting mono on both inputs, I'd check the 4 pin DIN plugs betwixt pre and power first, to see what's going on - switch off first obviously..

Once you've got the stereo problem sorted out, I can confidently recommend the Dada mods to the 33 boards and also revising the high-pass output filter (one cap on each output board). Transformed my 33 for the better and a LOT cheaper than a total Net-Audio mod, which turns it into a different preamp I feel My 303 was already heavily breathed on with cap and some resistor replacements, so I haven't touched that one.

[Rare Bird]

Multimeter with continuity bleep easiest way to check leads.
Re: the 4pin din signal for 303 Interconnect. The other Din ID's are on the back of the 33.

Pin 1: Signal Left
Pin 2: Ground
Pin 3: Signal Right
Pin 4: PSU

[DSJR]

Pin 4 isn't usually connected.........

[Rare Bird]

Thats right, it's a signal issue Dan as anyway.

[dantheman91]

Thats right, it's a signal issue Dan as anyway.

HI

any sujjestions in what i can do.?

Dan

[Rare Bird]

Could you knock up a passive pre amp of have another pre amp at hand with a fresh lead to establish it's not the power amp?

[dantheman91]

Din lead from the pre amp to the power amplifier and i think there connected up wrong because

din1
ground
wires clear and blue together
and
red and yellow wires together


Din 2
Ground
wires yellow and blue together
wires red and clear together


could be wrong

Dan