Kit building Quad 405 Clone

[JonLawes]

Hello ladies and gents, just a post to introduce myself really!

I am a keen audiophile who has never really had the money to buy myself any nice equipment. Anything I have owned has always been secondhand, and it says a lot about the humble quality of my kit that the highlight of my setup is a pair of matched Celestion Ditton XR15 speakers!

Anyway, I have decided that to teach myself a little more about the workings of an amplifier I would have a go at one of the cheap (and no doubt nasty) amplifier kits from eBay, in this case a Current Dumping Quad 405 clone from Tubeshunter. I work in an electronics based environment so there are lots of people here who can help if I come unstuck, but not many who know much about the audiophile side. They can tell me in depth semiconductor theory but don't know their Linn from their Leak!

So essentially I thought I would log in, say hello, and ask you to brace yourselves for some questions in the future!

Many thanks,
Jon.

[Bas Horneman]

Welcome Jon!

Wrt your questions. Fire away! Don't hold back.

[JonLawes]

Thank you, you may regret that statement later!

[JonLawes]

I was going to use a Quad 33 to drive this, mainly because its borderline affordable and is of around the right era to match my 405 clone! Is there any good reason to hold out for the Quad 34 or 44 in preference? I know they are much newer and may be a leap ahead, but as its only driving this 405 clone will that be so important? My budget is rather tiny...

All advice recieved in good humour!

[poynton]

It really depends on what sources you are going to use.

I originally used a 33 but changed it due to having to use adapters to the DIN sockets.

I changed to a Counterpoint tube preamp which sounded better and had the advantage of phono sockets.


Don't forget to post plenty of pictures of the build from day 1.

Andy

[JonLawes]

I managed to source a pretty well priced Quad 34 Pre-amp, I'm not averse to changing the connectors to something more useable (sorry if that offends any purists!) if required. Its got an MC input card with it. I'll probably mod it to take a CD input, plus an iPod interface I'm designing at the moment. Sorry if that makes anyone feel ill!

[JonLawes]

I scavenged an old hefty heat sink from a broken amplifier today; its quite sizeable but not quite as big as the one you normally see on the front of a quad 306! I need to make a custom enclosure I think, quite looking forward to it.

[JonLawes]

Here is a picture of the unit so far. Come up against a small problem as R11 doesn't have the component value written on the board so I'm awaiting the sellers reply to see if he knows it.

Its only mocked up in the photo; the heat sink isn't yet connected to the board, as the absence of power transistors will inform you! I'm a bit nervous; the construction bit I can do but if it doesn't work on completion (which lets face it given the obscure source of the kit) I am not going to be much good at fault finding.

The Big heatsink the two amp heat sinks are bolted to I scrounged off an old amplifier.

[JonLawes]

The sellers reply was "open circuit!". Looks like there isn't a resistor there after all!

[skidave]

Nice work. I will be watching your progress on this post.

I own a Quad 33 and 44. I like them both, but prefer the 44. It is a very quite preamp from a noise perspective. Both have great tone controls, but slightly different. I could get technical, but I think personal preference always wins.

I use the 44 in my main system and go between the 33 and a tube preamp I built in my family room.

Dave