WTD: Quad 405-2

[Wakefield Turntables]

I just fancy giving one a whirl. Anyone got one?

[spendorman]

Yes, I have one, but not for sale - at the moment!
Bought when the 405 first came out. About 1987 purchased the Quad 405-2 conversion kit. Years later, fitted Burr Brown op amps.

Shown below, including dust.

https://farm6.staticflickr.com/5244/5688134920_f2c8e3a769_b.jpg (https://flic.kr/p/9EDbkJ)QuadNAD (https://flic.kr/p/9EDbkJ) by A60man (https://www.flickr.com/photos/41679262@N02/), on Flickr

[Wakefield Turntables]

Alex you rotten bloody tease ;) It's not good gathering dust at your place, it could be gathering dust at my place. :eek:

[spendorman]

The pic shows 405-2 driven from pre section of NAD 3130.

Here is NAD/ 303

https://farm6.staticflickr.com/5027/5688335580_766e2e80bb_b.jpg (https://flic.kr/p/9EEcZo)NAD 303 (https://flic.kr/p/9EEcZo) by A60man (https://www.flickr.com/photos/41679262@N02/), on Flickr

[spendorman]

And for completeness, NAD 3130 / Radford STA25 III

https://farm6.staticflickr.com/5230/5687938702_b4e5b621d5_b.jpg (https://flic.kr/p/9ECb1E)NADford STA25 III (https://flic.kr/p/9ECb1E) by A60man (https://www.flickr.com/photos/41679262@N02/), on Flickr

[Wakefield Turntables]

Already got a Radford. My dream amp is the STA100.

[spendorman]

Yes, I know, I'm jealous.

But I do have a Williamson, the Daddy of valve amps.

[spendorman]

I recently tried the 405-2 with Rogers BBC LS3/6's, worked really well.

[Barry]

None of these posts is helping Andrew in his quest to find a Quad 405-2.

[Monty]

I have a 405 mk1 in very nice condition for £110 if that is of interest?
http://i1032.photobucket.com/albums/a405/paulperry86/Picture%20430_zpswgqsgbca.jpg
http://i1032.photobucket.com/albums/a405/paulperry86/Picture%20431_zpsrklwlsyr.jpg
http://i1032.photobucket.com/albums/a405/paulperry86/Picture%20432_zpsphkn6bcr.jpg

[Wakefield Turntables]

Paul I might take you up on that offer, that's a good price but I'm just gonna hold for a little bit longer for the /2 version which is what I originally wanted, your offer has been noted in bold capitals!

[orbscure]

Possibly a touch too expensive Andrew... but there is a nice example available from the outlet below:

http://www.retrotechaudio.co.uk/quad-4052---130815.html

I have no connection with the seller, but I've dealt with John @ Retrotech on more than one occasion and can recommend them 100%... :)

[spendorman]

If speakers are not a difficult load, 405-2 sound quality can be had from the 405 by just changing the op amps from LM301A to TL071. My experience is that it is an improvement. Cost is certainly less than £2.00

[Barry]

If speakers are not a difficult load, 405-2 sound quality can be had from the 405 by just changing the op amps from LM301A to TL071. My experience is that it is an improvement. Cost is certainly less than £2.00

Agreed, though you will need to add a couple of capacitors to ensure stability. Also I would increase the rating of the supply dropper resistors feeding the op-amp, as they run near their limit and can fail (It happened on mine!).

[Idlewithnodrive]

Possibly a touch too expensive Andrew... but there is a nice example available from the outlet below:

http://www.retrotechaudio.co.uk/quad-4052---130815.html

I have no connection with the seller, but I've dealt with John @ Retrotech on more than one occasion and can recommend them 100%... :)

That's still pretty good value IMHO.

[spendorman]

Agreed, though you will need to add a couple of capacitors to ensure stability. Also I would increase the rating of the supply dropper resistors feeding the op-amp, as they run near their limit and can fail (It happened on mine!).

Never did this and had no trouble, have done this conversion on several 405's. I know for some op amps changes are required. I have a feeling that on some late 405's TL071's were fitted from new.

There is something on Dada about this. It suggests removing capacitors if fitting particular op amps, but for the conversion I suggested, no changes needed. If I have read this correctly!

http://www.dadaelectronics.eu/ForumRetrieve.aspx?ForumID=317&TopicID=10644&NoTemplate=False

[SteveW]

Interesting thread, especially as I will be looking at the same down the line.
Just wondered if anyone had experience of these
http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=281708764649&category=14970&pm=1&ds=0&t=1441622795419

[spendorman]

I had seen those and was interested. They look good, but I have a feeling that they do not incorporate the crowbar protection circuitry that was fitted on all but the very first 405's. I could be wrong here, but I don't see it.

[mikmas]

That's still pretty good value IMHO.

At £255 a bit over the odds IMV .... I spent a good while looking before getting an RCA model in very good nick with original packaging for £200 of eBay - this was top end price really (bar the occasional nutter prices over the £300 :lol: )

[DSJR]

405's go for well over £200 now, so £110 is a bargain. As for updates - Quad fitted marginal supply caps at the time which were probably the best they could find at a fair price and size, which do tend to leak after ten years or more. I suspect any suspect ones would have been sorted by now though.

I should say that Quad changed the board layouts several times in the 405-1's life and the version 2 boards are issue 7. I have seen various versions by the way. Loads on the web about tweaking early versions and it seems that crossover distortion can rear its ugly head on earlier ones (and even the 909 to a tiny degree, according to Noel Keyward).

P.S. I'm also informed that the OPA134 can be an excellent op-amp to use in place of the LM301 and TL071, but really need firm confirmation on this...

[Wakefield Turntables]

Now sorted, watch this space!