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symon
14-03-2009, 17:12
Hello all,

so, I have a 33 and 405 sitting on a table ready to be connected to electricity and music and I have come across a potential problem.

I have a mains lead for the 33 which connects to a 3 pin plug (your standard type of plug), but it looks like the earth wire is not connected to the plug which goes into the 33.
Added to this, I only have a kettle lead for the 405 (yes, I know, I'll deal with that another day). But, the manual says I shouldn't earth the 405 to the mains plug if I am connecting it to a 33 - which I am. Apparently, the earth will be through the 33.
But, the 33 plug isn't wired up in a way I understand! Help!

Bear in mind my understanding of electronics is limited to negligible. However, my fear of breaking these things before I even hear a note is not negligible.
I can provide a photo of the 33 mains lead if that would help.

Bear in mind these were used by my brother in law before me, and I have got them from him in the same state he used them (minus the kettle lead), so I assume he just plugged in and played.

So, what do I do? Do I need to rewire the plugs? Or can I just carry on and plug everything in and start listening to music?

Thanks
Peter

symon
14-03-2009, 17:35
Actually, looking at the plug again, I realise I have not fully understood what is going on.

Let me try again. The plug which goes into teh plug socket on the wall is a three pin bog standard plug, with 2 wires and an earth coming out of it. This connects to the funky funny little connector that goes into the 33. But, the earth wire does not go into this plug and is just loose. There is an earth terminal on the back of the 33 which is separate to the plug input. So, do I just plug it in, attach the earth wire to the earth terminal and off we go.

Should I, then, disconnect the earth in the 405 plug? What happens if I don't?

Beechwoods
14-03-2009, 17:48
Earthing both the pre and power amps fully to their respective mains plugs will be fine from a safety perspective, the only thing is you may get 'ground loops' - hum - as a result of the 33 and 405 not having a shared earth. This may not be a problem in reality if both mains plugs go to the same wall socket or extension splitter.

The 405 manual has this to say (I think you have this anyway, but it's clarified things for me regarding how the 405 earths itself via the 33):


The supplied mains connector is terminated at one end by a two-pin plug. When the Quad 405 is used with a Quad 33 control unit, which should itself be earthed, the 405 will be earthed via the audio lead and should not be connected to the earth lead in the mains cable. In other cases, where the 405 must be earther directly, a three-core mains lead should be used.

So the 33 needs all 3 wires for the mains being connected, but if you're using the 405 with a 33 you only need wire up the Live and Neutral of the kettle plug for the 405 to the mains. Only if you're using the 405 with a different pre- do you need to fully wire the kettle plug earth to the mains.

So to answer your original question you need to fully wire up the plug of your 33 so it's properly earthed.

symon
14-03-2009, 17:57
So, stop worrying, plug it in and go! ??

Beechwoods
14-03-2009, 17:59
Yep!

symon
14-03-2009, 18:16
Cool. Here goes.

Beechwoods
14-03-2009, 18:47
Joy?

symon
14-03-2009, 18:51
Not yet - having a speaker issue now!:doh:
With my Denon amp I bi-wired out to my speakers. I can't do that with the 405 because the holes for connecting to the amp are too small for two speaker cables. Which is fine. But, I need something to use to link the connects on the speaker so that I can wire them up. Hence, my post in the DIY section.
I'm finding it hard to explain what I mean, but I hope it makes sense.

Beechwoods
14-03-2009, 18:57
I saw your other post just after posting above. I understand what you're after but have no experience of bi-wiring so will leave that one to one of the other folks here. I suspect that the solution is likely to be a very simple one though :)

symon
14-03-2009, 18:58
Yes - I think it is, but i can't picture how to do it.

Beechwoods
14-03-2009, 19:10
http://forum.ecoustics.com/bbs/messages/34579/109419.html

I think it's pretty safe to say you can link the two left terminals on each speaker and, the two right terminals on each speaker together (as per the pic on the above page) and then have the one pair of wires coming from the amp to either the top or bottom pair of terminals on the speaker. The signal is then shared between the top and bottom terminals ...

The Grand Wazoo
14-03-2009, 19:10
Not yet - having a speaker issue now!:doh:
With my Denon amp I bi-wired out to my speakers. I can't do that with the 405 because the holes for connecting to the amp are too small for two speaker cables. Which is fine. But, I need something to use to link the connects on the speaker so that I can wire them up. Hence, my post in the DIY section.
I'm finding it hard to explain what I mean, but I hope it makes sense.

The speaker cable you use should make the best possible jumpers for you. Measure the distance between the +ve binding posts on one of your speakers. Measure that distance along the speaker end of your +ve speaker cable for that channel. At this point strip bare a 1cm section of insulation from the cable. Screw down each post onto a shiny copper coloured bit! Repeat for the -ve conductor. Repeat for the other speaker.

Or more simply, cut a piece of cable off the same length as the distance between the posts plus a bit for error. Bare both ends. Use these to connect the two +ve posts only, as well as the jumper you've just made stick your cable into one of the binding posts. Rinse & repeat!

Spectral Morn
14-03-2009, 19:16
Hi Symon

With your amp switched off.

You need (I am assuming the Quad has holes for the speaker cable as opposed to Binding posts), a set of Michell or similar Banana plugs with a hole in the top. You wire speaker cables + and - into four plugs ( + and - for the right speaker and + and - for the left speaker)...this for your treble and then wire the + and - into the next set of 4 Banana plugs for the bass. You plug the bass cables right and left speaker into the speaker outlets on the Quad amp and then plug the remaining banana plugs into the holes in the top of the first set of four banana plugs.... making sure to get the left and right cables in the same order as the first set of cables. This allows you to bi-wire with only one set of speaker outlets.

Or as suggested above you can make jumper leads..to connect the binding posts on the back of the speaker.

Regards D S D L----Neil :)

symon
14-03-2009, 20:00
Nick: yes, the thing I am missing is the links between teh posts.

Neil: interesting. I'm not sure that would work with teh Quad. I'll take a photo of the back of it to show the connectors.

Chris: Thats the job! I think I understand. I hadn't thought of connecting them using the same piece of cable which connects to the amp. Great stuff.

Time to go playing again.

symon
14-03-2009, 22:10
Well. having eaten, wired up the speakers, connected everything and turned it on, I get..... nothing!:doh: Well, not quite nothing, I get a hum in the speakers, but no music from CD or record. Time to start exploring.:scratch:

spendorman
14-03-2009, 22:21
Original 405 had horrible push button connectors for speakers, could only take thin wires. Later 405-2 had 4mm sockets.

Easy way out, but some would not like is to use some suitable wire (just a few inches) to a chocolate bar (terminal block) connector.

Beechwoods
14-03-2009, 22:22
Have you tried each of the sources in turn, and have you got your DIN > Phono leads wired properly. Have you got 5 Pin DIN > 4 phono connector cables? Try each of the 4 phono connectors in turn. 2 should result in sound, the other two, not.

Stupid question, but is the 4 pin DIN > DIN between the 33 and the 303 connected up?

spendorman
14-03-2009, 22:23
I was never keen on the original 405, put TL071 op amps in mine (very easy as original op amps are in sockets) and the sound was vastly improved.

symon
14-03-2009, 22:32
Ok - yes, I think it is connected up properly...
2 - yes it haas the push button connectors.

First thoughts are
a) I just haven't connected the tt and cdp correctly.
b) the light doesn't come on on the 33.
c) could be the 33 plug - but I'm not sure how I can test this.

spendorman
14-03-2009, 22:37
No light on the 33 is probably the clue (unless bulb is gone and thats unusual).

Check that power lead to the 33. Check fuse in 13A plug, obvious, but I've been caught with this. Check the small mains plug that goes into the 33 (mains unplugged of course) a wire may have come loose in this.

symon
14-03-2009, 22:40
Ok, turning up the volume on the 33 increases the loudness of the hum in the monitors...

spendorman
14-03-2009, 22:44
Is light on in 33?

Beechwoods
14-03-2009, 22:46
Have you got the 303 'mains cable' plugged into the back of the 33? When you switch on the 33 does it 'turn on' the 303? It does sound like the 33 is getting power, if the volume control affects the hum into the 303.

Just going back to my earlier comment - have you tried connecting your sources to each of the inputs in turn? The 'Tape' input and 'Disc' inputs have different routes through the 33 to the 'Radio' inputs. The Tape board may have blown but this wouldn't affect the 'Radio' inputs.

spendorman
14-03-2009, 22:46
And another silly question, are the plug in boards in the 33? Long time since I used mine.

symon
14-03-2009, 22:50
Right..
1. No lights on the 33
2. I just have the tt plugged in at the moment - no change
3. lights come on the 405 - which has it's own mains lead
4. Yes, the 4 pin-4pin is connected.
5. Playing with the mono and stereo switches affects the noise in the speakers
6. Yes, the cards are in the back - correctly as far as I know.

Next step is to unplug the tt and try with the cdp

Beechwoods
14-03-2009, 22:51
I've just had a thought re-reading your comments from the start and thinking about the mains cable into the 33.

I got my mains cable of eBay:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=190284616712

It is a 3 Pin Round Bulgin plug to 3 core cable (I was thinking about the 2 core cable between the 33 and the 303 in my earlier post). The picture in the eBay ad made me think.

I assume your mains input into the 33 ends with the round 3 pin?

Just thinking you might be plugging the mains into the 2 pin outputs from the 33.

Perhaps some pictures would help!

Aaaargh! :doh:

symon
14-03-2009, 22:56
Pictures coming soon.

Things get weirder.

I have the cdp plugged in and playing - and a very very tiny amount of sound is coming out of the speakers. With the volume turned up to nearly full I'm beginning to think that the problem might be
a) the speakers
b) the tt

But, for now I have a tiny sound - sounds like what you can hear when somebody has their in ear headphones on very loudly!

Beechwoods
14-03-2009, 22:58
I wonder if you've succeeded in connecting both parts of your bi-wired speakers together properly. You may just be getting noise from your tweeters. Do you get any hum at all from the mid/woofer cones?

spendorman
14-03-2009, 23:00
I have never known a bulb blow in a 33, but it must happen. Perhaps take the cover off the 33 and check that the bulb is screwed into its holder fully. (think its a screw in). At least with the light going you will know that you have power to the 33.

spendorman
14-03-2009, 23:06
It's so long since I used my 33, I could not remember if there are plug in boards inside, looks like there are:

http://www.net-audio.co.uk/jpgs/quad33opin.jpg

Are these in? not just the tape and phono boards.

symon
14-03-2009, 23:12
Change of speakers - not biwirable - same result.

The 33 and 405 were used successfully by my brother in law - who had them before me.

Still, I'll disconnect everything and open it up.

Beechwoods
14-03-2009, 23:18
Something may have just got knocked out of alignment in storage - ensuring all the boards are seated properly may cure the problem :)

symon
14-03-2009, 23:28
A-ha! The cards are there - but were loose. Have now been pushed in.

And, maybe I've been a bit stupid. I assumed/thought that you had to push in the buttons to select a source - so, push in tape to get the tape source, push in disc to get the record. I just pushed the tape button out and got sound! :uhho: I'm going to rewire my proper speakers and connect the tt and see what happens.

Beechwoods
14-03-2009, 23:34
Super, Peter!

The 'Tape' button overrides the other buttons. 'Disc, 'Radio 1' and 'Radio 2' are all exclusive. Make sure ' Tape' is out if you want to listen to any of the others. The 'tape record' loop through & output to a tape deck if connected is always working regardless of the 'Tape' button.

You can download a manual for the 33 at Vinyl Engine.

Registration is free :)

Spectral Morn
14-03-2009, 23:37
WELL DONE SYMON....:mex:

Sorry I could not help much, I don't know alot about Quads, except Quad 2 amplifiers. Glad its working for you now.


Regards D S D L----Neil :)

symon
14-03-2009, 23:48
Ha - I have the manual for the 33. I'll be reading it a bit more closely now! duh

Well, I'm not totally there but at least I am getting some nice noises. I don't think I've fixed the speakers properly - getting some odd effects, so I need to go back to those and explore more. And the tt still isn't producing any noise. I need to check the tt on the denon amp tomorrow.

Thanks for all your help guys. Sorry for being a bit stupid!

Beechwoods
14-03-2009, 23:55
:lol: It's all part of a great adventure, and the manual isn't the clearest tbh anyway!

Have a good one.

The Grand Wazoo
15-03-2009, 00:17
Well done, even the most expert 'experts' get floored by the tape loop every now & then.

Of course, you do realise the definition of an 'EXPERT' don't you?

An EX is a Has-Been............And a SPURT is an uncontrollable drip.

ENJOY YOUR QUADS

symon
15-03-2009, 00:20
I'm hoping too. Just need to fix the speakers. I had tried using extra cable to link the HF and LF. Now I'm going to try using the cable that connects to the 33.

symon
15-03-2009, 01:46
So, as I sign off for the night, here is where I've got to:
1. the 33 and 405 work and music is conveyed to the speakers, but
2. I haven't been able to get any vinyl sounds yet (could be the tt)
3. The sound from CD is weird - at the moment the vocals aren't coming through very well at all. On one CD it sounded like they were coming from the bottom of a well (and they shouldn't sound like that). And the overall volume is very quiet.
4. The speakers are bi wirable. I have used speaker cable as jumpers/bridges/links between the LF and HF posts. I have connected the speaker cable connected to the 405 to the LF posts. Could there be a fault here which is causing the odd effects?

Anyway, more testing and playing tomorrow at a slightly higher volume.

Beechwoods
15-03-2009, 08:00
You may find the levels coming from your CDP are too high for the inputs on the 33. The easiest solution is to use the 'Tape' input. You can remove the 'Tape' board and set the two 'Replay' screws to the medium ('M') position. This may already have been done - it's easy to check. See the left side of this pic.

http://homepage.mac.com/beechwoods/AOS/quad33_tape.jpg

Likewise, have you checked the 'Disc' adapter board is set to match the output of your Turntable? Most cartridges will be high output ones, and will work with the Disc board in the MC2 position. Some, like the Denon 103, will be low output, which will need the Disc board in the MC1 position. You select the position of the Disc board by rotating it and inserting the right side into the Quad. If you have a low-output cart going into the MC2 positioned board, you won't hear much if anything out of the Quad.

Primalsea
15-03-2009, 10:43
Well done on getting it working, it's a real pisser when things just dont work but usually for me its nearly always been a simple thing. The simple things going wrong often have the most disasterous looking faults.

As Jasper Carrot said "We all make mistakes, said the dalek as he climbed off the dustbin"

symon
15-03-2009, 13:42
Well, I thought I would begin today by going back a step and putting my old amp into the equation. The idea was to test what the speakers sound like with the bi-wire jumpers in, and to make sure the tt worked.
And the result is that the speakers sound fine and the tt works.
Which means the problems are all related to how the 33 and 405 are set up.
So, to restate the problems:
1. no sound from the tt
2. the sound from the speakers when playing a cd is completely wrong. Sound is coming out, but vocals are very quiet and the overall volume is very low.

So, time to connect the speakers, tt, and cdp back to the 33.

DSJR
15-03-2009, 13:46
make sure that pins 3 and 5 of the din plug are used for playback, as low level often means the signal's going into the record circuits instead (been there, done that).

The Grand Wazoo
15-03-2009, 13:47
Why don't you see if you can connect the tape output of your old amp to the Quad power amp inputs? This way the old amp will act as a pre & that might help you isolate the problem to the Quad pre or power.

DSJR
15-03-2009, 13:55
Is the tape-out variable? if not, you may blow the speakers up...

symon
15-03-2009, 14:06
Ok - now here's a weird thing. There are 5 inputs on the back of the 33 - 1 for tt, 2 for tape, 2 for radio.
If I put the cdp through the proper tape input, it sounds wrong. However, if I put the cdp through the Radio 1 (FM, stereo) input and press in the two mono buttons (rather than the stero button) I get proper sound at a decent volume :scratch::mental:

So, does that mean I'm listening to a stereo source through a mono output?

Does this make any sense to anyone? I'm very confused.

symon
15-03-2009, 14:16
So, to add further info, I put on whole lotta love - and the solo that comes in at the end of the experimental bit just isn't there - well, it's a faint echo in the background. So, there's something odd going on between the cdp, the 33, the 405 and the speakers.

spendorman
15-03-2009, 14:29
While you are still having problems it may be wise to put in the voltage / power limiter resistors in the 405 so as to reduce the chance of blowing speakers.

They may be in already.

In 1976 when I got my 405, virtually the first thing I did was to blow a KEF B200.

symon
15-03-2009, 14:33
I think I almost blew them just now! I had a button pushed in and the volume up. I pushed the button out and the speakers farted very very loudly!!! I don't think I've broken anything though.

spendorman
15-03-2009, 14:37
I think I almost blew them just now! I had a button pushed in and the volume up. I pushed the button out and the speakers farted very very loudly!!! I don't think I've broken anything though.

Err, think most have done similar.

spendorman
15-03-2009, 14:42
Not a very helpful suggestion right now, but some 5 pin Din to phono leads and 4 pin Din to phono may be useful in testing out the Quad stuff.

If your CD has a volume control you could connect it straight to the 405 to check the power amp.

spendorman
15-03-2009, 14:46
Once the power amp has been confirmed as OK, perhaps connect the 33 to it using the 4 pin Din to 4 Pin Din lead. (it is possible that you have a faulty one of these cables).

symon
15-03-2009, 14:49
Hmm, I was wondering about the cables.
I don't think you can connect direct to the 405, without going through a pre-amp.

I'm not sure I have the ability to connect my Denon to the 405, with the Denon acting as a pre-amp.
At the moment, I only have one set of connectors.

spendorman
15-03-2009, 14:52
Hmm, I was wondering about the cables.
I don't think you can connect direct to the 405, without going through a pre-amp.

I'm not sure I have the ability to connect my Denon to the 405, with the Denon acting as a pre-amp.
At the moment, I only have one set of connectors.

Yes, you can connect 405 straight to a CD, no pre needed, but a volume control is. You will need leads though.

I have run my 405-2 straight off a CD player, off PC sound card etc. etc.

spendorman
15-03-2009, 14:54
You can test out that 4 pin din to 4 pin din lead with torch bulb and battery if you do not have a meter.

symon
15-03-2009, 15:00
You can test out that 4 pin din to 4 pin din lead with torch bulb and battery if you do not have a meter.


How?:confused:

spendorman
15-03-2009, 15:07
Connect one end of bulb to battery with a bit of wire, other end of battery to another wire so you have a free end.

Other end of bulb connect another wire, so you have another free end.

When both free ends are touched together, bulb lights, this gives you a continuity tester.

Check out from pin 1 of one end of Din lead to pin 1 of other end of din lead and so on.

spendorman
15-03-2009, 15:18
Just looked at a cable that I use to connect 405-2 and 303 amps. Pin 4 is not used, pin 2 is earth pin 3 signal, pin 1 signal.

Pin 1 is connected to Pin 1 (at other end of lead)
Pin 2 is conn to Pin 2
Pin 3 is conn to Pin 3

symon
15-03-2009, 15:20
Ok - cool, will try that.

Here's a photo of the back of the 405:
http://farm4.static.flickr.com/3548/3355990183_2e5ab40a3e_m.jpg

spendorman
15-03-2009, 15:22
Looks like a 405 to me, but what are those two things to the left of the Din socket? Phonos? If so, not original, photo is a bit small to see clearly.

symon
15-03-2009, 15:25
Bigger photo:
http://farm4.static.flickr.com/3548/3355990183_2e5ab40a3e_b.jpg
Don't know what the white things are and I don't know how to get them out. Although, I suppose taking the case off might give me the answer.

spendorman
15-03-2009, 15:29
Look like pots (volume controls) definately non standard, but understandable

symon
15-03-2009, 15:30
Wait - volume controls? Hmmm, let's see....

spendorman
15-03-2009, 15:33
Most people put phono sockets in those two holes that are normally filled with grommets. Here is my 405-2 (was 405). I put the phono sockets in. Also note the 4 mm loudspeaker sockets, part of the 405-2 conversion.

symon
15-03-2009, 15:35
Yes, they are volume controls... but they are not the answer.

spendorman
15-03-2009, 15:38
It may be worth opening the 405 to see how they are connected, perhaps take photo, you can also check to see if power limiters are in.

Just two pozi screws to open.

symon
15-03-2009, 16:00
Pictures: Inside 1
http://farm4.static.flickr.com/3600/3356103699_2ce138d873_b.jpg

symon
15-03-2009, 16:01
Inside 2:
http://farm4.static.flickr.com/3601/3356102307_90a01e937b_b.jpg

symon
15-03-2009, 16:02
Inside 3:
http://farm4.static.flickr.com/3424/3356101247_efff7c65a4_b.jpg

symon
15-03-2009, 16:03
To be honest - I opened it up, looked in and thought 'Nope, no idea what this all means' :scratch::confused::lol:

spendorman
15-03-2009, 16:12
Cant really see the wiring for the added pots, but let us assume that they work. Were they turned right up, down or in the middle? Obviously right down, one would probably not hear much from the amp.

Cant quite see if power limiter resistors are in they would be in two holes in each channel, marked R11 between the holes. This resistor just pushes into the two holes.

spendorman
15-03-2009, 16:18
This is a 405 board, probably a later production than yours. The limiter resistor is indicated in the circle. They just push in. Nothing in the holes gives full 100W/ channel.

symon
15-03-2009, 16:26
Nope - two holes unoccupied, so the limiters aren't in. And, I don't have them.

The extra pots are turned up full. They do have an effect, but nothing special at the moment. They just make a quiet sound slightly less quiet.

symon
15-03-2009, 16:30
I can't see how I would connect anything other than the 33 to the 405. I'm assuming this is beause of the extra volume pots.

spendorman
15-03-2009, 16:31
The resistors are just standard resistors, forget the value, one can tell from the colour codes (I forget the codes!) will probably be in the Quad instructions though.

So unless anyone has any other ideas, check out the 4 pin to 4 pin Din lead. Make or get a cable to connect 405 direct to CD.

spendorman
15-03-2009, 16:37
R11 is power limiter resistor 1.8 K Ohm two needed of course.

spendorman
15-03-2009, 16:48
Just seen a test on the 405, they got approx 120W per channel into 8 Ohms, so be a bit careful, don't know your speakers, may be OK with that.

symon
15-03-2009, 16:49
I'm thinking of taking a rest for a bit - headache, no spare torch lightbulbs!

spendorman
15-03-2009, 16:52
OK, If you were nearer, I would sort it.

spendorman
15-03-2009, 16:59
I can't see how I would connect anything other than the 33 to the 405. I'm assuming this is beause of the extra volume pots.

You would need 4 pin din to phono cable.

symon
15-03-2009, 18:03
Ah, ok.

The CD player I'm currently using doesn't have a volume control. But, I have another in the loft which does (I think).
Thanks for your kind offer of help, and for all you have done so far.

symon
15-03-2009, 18:21
I might get this:
http://cgi.ebay.co.uk/2-PHONO-SOCKETS-TO-4-PIN-DIN-PLUG-FOR-QUAD-EQUIPMENT_W0QQitemZ310089556294QQcmdZViewItemQQptZ UK_Computing_CablesConnectors_RL?hash=item31008955 6294&_trksid=p3286.c0.m14&_trkparms=72%3A1683%7C66%3A2%7C65%3A12%7C39%3A1%7C 240%3A1318

I'm thinking I could use that for a CD player straight in to the 405, and also to link the pre out on my Denon to the 405.

spendorman
15-03-2009, 18:32
I might get this:
http://cgi.ebay.co.uk/2-PHONO-SOCKETS-TO-4-PIN-DIN-PLUG-FOR-QUAD-EQUIPMENT_W0QQitemZ310089556294QQcmdZViewItemQQptZ UK_Computing_CablesConnectors_RL?hash=item31008955 6294&_trksid=p3286.c0.m14&_trkparms=72%3A1683%7C66%3A2%7C65%3A12%7C39%3A1%7C 240%3A1318

I'm thinking I could use that for a CD player straight in to the 405, and also to link the pre out on my Denon to the 405.

Yes, this should be useful, I have bought from that seller myself.

Some similar but 5 pin din to phono may be useful for the inputs.

You could also go from a personal stereo (ipod etc) to the 405.

symon
15-03-2009, 18:40
Yes - I might get one of those later. I have a decent tt which needs fixing (lord help me!) which I might need one of those for.

I'm just going to dig out my other cdp to see if that is the source of the problem. I doubt it will be, but it's a test I can do now.

Beechwoods
15-03-2009, 18:41
I use these for my inputs into the 33. They're Philips, though are not in branded packaging. Very nicely made for the price.

http://cgi.ebay.co.uk/NAIM-QUAD-5-PIN-DIN-TO-PHONO-OFC-INTERCONNECT-CABLE_W0QQitemZ220373807456QQcmdZViewItemQQptZUK_C omputing_CablesConnectors_RL?hash=item220373807456&_trksid=p3286.c0.m14&_trkparms=72%3A1300%7C66%3A2%7C65%3A12%7C39%3A1%7C 240%3A1318

symon
15-03-2009, 19:07
Nope, a change of cdp changes nothing.

symon
15-03-2009, 19:32
Nick, which input in the back of the 33 do you use? Tape or radio?

I'm defintiely confused. I just connected the cdp to the radio 1 input. With the stero button in the sound is weak. With the two mono buttons in the sound is strong and full, but in mono obviously, with particular bits of the music buried. So, it's not as I want it, but it's pointing in the right direction. It would seem to me from this that the stereo function is off in some way.
Also, when I put the lead in the radio 2 button and pressed the stereo and mono buttons in a random way (I was getting confused) the Quad light came on. But, I got very little sound and when I pressed more buttons, the Quad light went off.
So the Quad light works, but only when a mysterious sequence of buttons are pressed.
Sound comes out loud and strong, but not when the tape input is used, or when teh stereo button is pressed in.

Does this shed any further light on anything??

DSJR
15-03-2009, 19:40
Try radio 2 instead. I have a dim and distant memory about this.....

I may have got my wotsits in a doodah, but I seem to remember that the radio 1 input was setup for the pin 1 mono output of the AM tuner Quad did...

symon
15-03-2009, 19:44
I think it might be the other way around. The manual suggests 1 is for stereo and 2 is for AM. I did try it in the Radio 2 input and got very little if no noise (but the light came on!) I'll try again though.

spendorman
15-03-2009, 19:45
I bet the Quad lamp is loose, pushing buttons just shook it a little making contact. Take cover off 33 and check bulb is screwed in fully.

As for the other 33 problems, a bit of a mystery. CD should work into Tape replay and Tuner input, but tuner input may be too high a sensitivity, think it was particularly sensitive for the FM3 which had little output, possibly about 100mV?

symon
15-03-2009, 19:46
No output from the other radio input at all, unless it's very very quiet.

symon
15-03-2009, 19:48
I bet the Quad lamp is loose, pushing buttons just shook it a little making contact. Take cover off 33 and check bulb is screwed in fully.

As for the other 33 problems, a bit of a mystery. CD should work into Tape replay and Tuner input, but tuner input may be too high a sensitivity, think it was particularly sensitive for the FM3 which had little output, possibly about 100mV?

I thought about that. It's a very tight squeeze to get to it though. I don't feel confident enough to move other bits just to get the light working. But I will dive in again and try.

I am beginning to wonder if something else is loose inside. I might open it up again and push a few things just to make sure everything is in place.

spendorman
15-03-2009, 19:50
Has the 33 been out of use for a long period?

symon
15-03-2009, 19:52
I don't think so. It's been sat on my floor for a month or so. I'll have to check about what was use it had before that.

spendorman
15-03-2009, 20:05
Only thinking that the selector switch contacts may have corroded, but its not that likely. My 33 was in a loft for about 8 years and was still OK.

spendorman
15-03-2009, 20:07
Have a look at the pliug in boards inside the 33, carefully take out and look at the contact area. Don't use any abrasive to clean them though. Put boards back in and try again.

spendorman
15-03-2009, 20:20
Just been looking at the service supplement for the 33, it does say that the sockets for the internal plug in boards

"have been known to cause confusing symptoms of erratic operation, attributed to other factors such as pushbutton switches, solder joints etc."

There is a cure, I can scan this in if required. Think it would be worth tying what I said before, removing boards checking and putting back in, before doing anything else.

symon
15-03-2009, 21:02
Hmmm - took out the removable cards inside. They all look fine to me. The connections look clean enough. No change. Using the Radio 1 input, tiny sound on the stereo button, fuller sound on the Mono buttons.

Would photographs of all the removable cards help?

spendorman
15-03-2009, 21:06
I will scan in the part of the service supplement about the contacts

spendorman
15-03-2009, 21:11
Quad service info

symon
15-03-2009, 21:18
OK, I'll give that a go. Does it matter what the probe is made from?

spendorman
15-03-2009, 21:24
OK, I'll give that a go. Does it matter what the probe is made from?

Never needed to do this, I suppose something like a plastic knitting needle could be used, sharpened as shown. However, be careful that it does not break off leaving a bit that will be difficult to remove and don't bend the contacts much.

I give no guarantee!!

symon
15-03-2009, 22:00
no change

symon
15-03-2009, 22:01
What I don't understand is why it can be so nearly there when payed on the Radio input with both mono buttons pushed in, yet be so far from perfect when the stereo button is used.

spendorman
15-03-2009, 22:08
What I don't understand is why it can be so nearly there when payed on the Radio input with both mono buttons pushed in, yet be so far from perfect when the stereo button is used.

That must be a clue.

Perhaps someone else can come up with a suggestion.

symon
15-03-2009, 22:16
I'm at a loss now. I don't know enough to fiddle.

The other clue is that I haven't got the tt playing properly through the set up yet.

spendorman
15-03-2009, 22:19
What is the TT? Does it work through another amp?

Dave Cawley
15-03-2009, 22:19
The probe should of course be metal of any type. But this doesn't rule out incorrect wiring, which for a £20 pound bet to charity I'll put my hat on.

Dave

symon
15-03-2009, 22:22
The tt is a Technics sl-3, with an mm cart. Yes, it does work through the Denon.

When you say incorrect wiring, what do you mean? By me or in the Quads? It has been working prior to my getting it. Although, a p hone call over the next day or two will be made to confirm lots of detail I don't have at the moment.

spendorman
15-03-2009, 22:25
Probe for testing as in 4th para of course needs to be a conductor, so metal is Ok, but the probe for para 5 could be something else.

spendorman
15-03-2009, 22:31
The tt is a Technics sl-3, with an mm cart. Yes, it does work through the Denon.

When you say incorrect wiring, what do you mean? By me or in the Quads? It has been working prior to my getting it. Although, a p hone call over the next day or two will be made to confirm lots of detail I don't have at the moment.

So TT is OK, mm cart OK for 33.

You have other equipment so its not that you will be without music. Perhaps have a word with previous owner. Get a cable so that you can check out power amp without using 33.

You could do the metal probe thing into the tape replay socket/ tuner socket and listen for hum.

Are you sure your Din plugs into the 33 have the right pins connected?

symon
15-03-2009, 22:36
Yeah. First things first - make the phone call. I have heard music through these so I know they have worked recently.

Oh, and I don't have a cdp with a volume control. So, I guess the only other test I can do is to use my Denon as a pre amp.

spendorman
15-03-2009, 22:45
When it's going, I would recommend for sound quality, replacing the op amps with TL071, it makes a big difference, going to exotic ones does not do much more and may need other changes (IMHO). TL071 are very cheap. Just make sure that they go in the sockets (most 405 boards had sockets) the right way round.

The 33 is not bad, but it certainly limits the performance of my well adjusted 303's. For years I did not realise how good the 303's are until I bypassed the 33. The 44 also limits the sound quality (again IMHO).

That is not to say that the 33 and 44 are really bad.

symon
15-03-2009, 22:56
Well, they should be a step up for me - once I get them working!
I'll see about fiddling inide when I feel more confident about it. At the moment I don't really know what you mean. Which is fine. I can learn about that another time.

From memory, I'm sure they have been serviced within the last year or two, so there really is no reason why they shouldn't be working.

As for the leads, as far as I can see there isn't a way to connect them incorrectly. And, as I say, it worked before they worked before I got them - using the leads I have now apart from the kettle lead for the 405.

The only thing I have found which seemed to be slightly wrong was the cards inside the 33 being loose.

spendorman
15-03-2009, 23:02
So you are using the same 5 pin Din input plugs/ leads that the previous owner used? How many?

The op amp change is easy, there is only one 8 pin chip on each board.

My fav amp in about 40 years of messing with Hi Fi is Radford STA25 valve amp, wonderful.

symon
15-03-2009, 23:05
1 x 4 pin to 4 pin, and 2 x RCA to 5 pin.
Again, if I remember right these were made for this set up.

spendorman
15-03-2009, 23:06
So it's unlikely that both RCA to 5 pin Din are faulty, presume that you tried both.

symon
15-03-2009, 23:07
Just out of interest, what should I get to do a proper test of the cables? (ie, other than a bulb and a battery!)

symon
15-03-2009, 23:08
So it's unlikely that both RCA to 5 pin Din are faulty, presume that you tried both.


Yes, I switched them around and have unplugged them and mixed them up quite a few times.

spendorman
15-03-2009, 23:10
I recently bought an old A&R Cambridge A60 amp, it has Din inputs, came with a lead (Din to RCA) it was connected incorrectly and initially thought amp was faulty. It was the lead amp was fine.

spendorman
15-03-2009, 23:12
It could be that the two Din to RCA that you have, the owner used to take record output from 33 to tape recorder. These would be connected incorectly for input.

symon
15-03-2009, 23:14
I can get replacements if need be. It just seems unlikely that they would be wrong given the fact that the set up was used previously and quite obviously worked. I'll be phoning the previous owner tomorrow for a chat about all this anyway.

symon
15-03-2009, 23:15
It could be that the two Din to RCA that you have, the owner used to take record output from 33 to tape recorder. These would be connected incorectly for input.


They were used with a cdp and turntable. No cassette decks in sight.

spendorman
15-03-2009, 23:17
Just out of interest, what should I get to do a proper test of the cables? (ie, other than a bulb and a battery!)

Continuity test is fine using battery/ bulb or multimeter. However you must make sure that the correct pins of the Din plug are used. The Din plugs often come apart and the pins are marked.

Multimeter, £4- £10 on ebay etc, Maplin etc.

spendorman
15-03-2009, 23:21
I can get replacements if need be. It just seems unlikely that they would be wrong given the fact that the set up was used previously and quite obviously worked. I'll be phoning the previous owner tomorrow for a chat about all this anyway.

Yes but if your two din/ RCA were used to take output of 33 to tape deck, the wrong pins of the Din plug will be connected whe using these adaptors for replay.

spendorman
15-03-2009, 23:23
To be sure you could get a Din plug/ lead terminating in four RCA, two of those will be correct.

spendorman
15-03-2009, 23:24
Just bear in mind, 5 pin Din sockets can have two inputs and two outputs.

spendorman
15-03-2009, 23:32
They were used with a cdp and turntable. No cassette decks in sight.

Ah!

symon
16-03-2009, 21:30
Well, I thought I'd try a few other things. So, I took the leads connecting the tt to the 33 and used those for the cdp - no change.
I then thought about the speaker cable and swapped the connections around to the 4 different ways I could think of to reconnect - just in case I had wired up the speakers incorrectly. No change.
The light came on briefly when I pressed some more random buttons (different ones to yesterday) - although I think the common link was the Radio 2 button.

So, I'm still confused.

The units were serviced a year or two ago by a chap in Exeter. When they in use before me, they had a tt and cdp going into a mixer into the 33 (I think).

symon
16-03-2009, 22:44
So, to help rule out other possibilities I have a cable on order so that I can connect my denon amp to the 405. That'll take a couple of days to arrive. Ah well. Bit bummed I can't get them to work properly.

spendorman
17-03-2009, 00:47
Simples (I like that advert on TV).

Forget 33 for now, just test out 405 with another input, say straight from CD

"they had a tt and cdp going into a mixer into the 33 (I think)."

So the mixer fed the 33! Those 5 pin Din to phono may be suspect.

symon
17-03-2009, 10:30
Hmm, I was wondering if that might be a clue.
I suppose buying new cables will be cheaper than taking it to a repairman of some sort.

spendorman
17-03-2009, 11:43
Absolutely!

But you should be able to open up the Din plugs to check if correct pins are connected.

symon
17-03-2009, 12:32
Yes - ok. I shall look into that. My own lack of confidence comes into play here as I'm not sure I would know what I was looking at. However, I haven't really done any research to change that yet. I shall ponder that one tonight.

spendorman
17-03-2009, 12:36
well, there are five pins, centre one is earth so that is probably right. that leaves just four pins. two will not be connected, those may be the ones you need to connect to.

symon
17-03-2009, 12:58
OK, well that makes sense. I'll open one up tonight and have a look.
I can see a new soldering iron on the horizon!

spendorman
17-03-2009, 13:21
The Quad 33 instructions should give pin numbers for inputs/ outputs.

If you do not have it, it should be easy to download somewhere. Any problem, I will find one.

symon
17-03-2009, 13:22
Yes, I have it. I was planning to look in there for the answer. Mind you, it's not the most well written instruction book ever!

DSJR
17-03-2009, 13:52
if you carefully open up a 5 pin DIN plug wired for playback, you'll see the earthing screen connected to the top cantre pin. The left and right signal wires should be connected to the two pins to the RIGHT of this as you look from the rear (pins 3 and 5).

If you pop into your local TV shop and buy a "Bandridge" style DIN-4 phono lead, the yellow should be "left play" and blue is "right play," White or black is "left record" and red is "right record."

I hope this helps you get sound anyway!

Once you have sound, the next thing to make sure of is that the 33 is usually overloaded by a CD player. Decent attenuated leads are available from Chord Co and, I think, Flashbacksales, or you could buy some Rothwell attenuators. A good working 33 is worth this effort and can delight with an expansive midrange, if a little "curtailed" by modern standards. 33's can also be modified to different degrees.

Try here for an easy way to allow the disc adaptor to accept CD on it's spare position -

http://www.geocities.com/ResearchTriangle/Lab/6722/quad33cd.html


[edit]

Is a 33/405 worth persevering with?

My answer is yes, as I was a '60's kid and the 33/303 were something I drooled over. The basic performance can be excellent as long as the caps aren't knackered and the thing isn't being overloaded... There are numerous companies about who can do wondrous things by way of tweaks, although the power supply and level matching ones on the 33 should be looked at carefully before proceeding. The 405 needs to loose most of its over-protection and there are numerous articles about component layout affecting distortion on those pre mk2 amp boards. If you're unable to mess about with a soldering iron, then DADA now make 405-2 boards and can supply modern, dual reservior supplies which improve the performance further. You'd have to spend a thousand or two to get something genuinely better than a properly fettled Quad IMO...

symon
17-03-2009, 13:58
Thanks for that.
As far as I know, the 33 has already been modded for a cdp input. But, I will have to check this.

spendorman
17-03-2009, 18:56
Actually, according to the instruction booklet, the pins connections are marked on the back of the 33 pre amp.

symon
17-03-2009, 21:34
Ok, noob question: How do I read the diagrams in the quad 33 booklet and circuit diagrams? Where it shows the layout of the plug, is the plug facing you or facing away. So, on page 6 of the booklet there is a diagram of the connector with numbers on the pins. Is the diagram facing me - with 5 and 3 on my right, on the bottom of the diagram - or are 5 and 3 on the left?

Sounds to me like a stupid question, but I'm feeling pretty stupid right now.

spendorman
17-03-2009, 22:24
Page 6 seems to show a pic of the socket as viewed looking at the back panel of the 33

spendorman
17-03-2009, 22:26
If one opens up the plug (if possible, some are moulded on) the pins are usually numbered on the black plastic that they are set in.

symon
17-03-2009, 22:52
I just looked more closely at one of the connectors. Looks like it's wired up as 1 4 2

symon
17-03-2009, 22:57
I'll have to find out what exactly my brother in law was using. If the plugs are wired incorrectly for me, they would have been incorrect for him. I'm beginning to think he was going straight into the 405 and not using the 33...

spendorman
18-03-2009, 13:29
All you have to do is take the covers of the Din plug, hold it up to the back of the 33 and see if the wires in the plug line up with the correct pins on the socket.

DSJR
18-03-2009, 15:00
Pin 1 is LEFT RECORD and 4 is RIGHT RECORD

That explains your problem, as you need pins 3 and 5 (the ones on the right when looking at the rear of the plug) for playback..............................

FFS, Flashbacksales do a smashing interconnect for Naim and Quad amps, DIN - 2 Phono and don't charge a fortune for it. Order the one with standard non-locking DIN plug - pins 3 and 5 connected!

symon
18-03-2009, 22:57
So, new leads ordered - hopefully they'll get here tomorrow.
What I got today was a lead which allowed me to connect the Denon to the 405. Stereo sound ensued! Now I'm really looking forward to connecting up the 33 to the 405 and hearing what it can do.

DSJR
19-03-2009, 12:42
Hopefully, nothing dire.....

Preamps with active line circuits were the scourge of the audio system and many still are I reckon. The 33 suffers input overload if it's not dealt with, a low voltage power supply, noisy controls with age and knackered capacitors too in some places. Add to that the bandwidth limiting and you'll get some idea.... To be fair, a fettled one has a lovely midband and pleasant bass and treble. You just have to work at it to make it competitive with todays designs, which can use simple, non-bandwidth limited circuits, better earth paths and modern thinking on the power supplies (I'm NOT thinking of Naim here, who's basic preamp design pre-dates the 33 I understand and all those boxes is profit chasing IMO).

Good luck anyway, and get the 405 relieved of some of its limiting too :)

symon
19-03-2009, 13:09
My plan is to get it all working as is and get used to how it sounds like now. Then I'll start fettling! Starting with things like making a mains cable for the 405, doing up a Lenco 75, buying a decent CDP. Once I have the main elements in place I can then look to improving those elements - and I shall be returning to this thread to pick up on the ideas that have been put forward. Thanks for all the help and advice.
I'm at the start of listening through hi fi equipment. I don't want to start trying to improve things until I have got used to how they sound in their normal state. I don't have the experience (trained ears?) to make much sense of fettles yet ;)

symon
20-03-2009, 13:16
The new leads have arrived! So, tonight I should get the full Quad experience at last!!

spendorman
20-03-2009, 13:34
pin back your lug-holes

Marco
20-03-2009, 13:51
The tension is killing me! :eyebrows:

Marco.

symon
20-03-2009, 14:02
Me too! I'm stuck at work knowing that the solution is waiting for me at home....

symon
20-03-2009, 21:46
Hurrah! Sound, glorious sound!

Beechwoods
20-03-2009, 21:47
:respect:

spendorman
20-03-2009, 21:48
Hurrah! Sound, glorious sound!

Well done!!

Beechwoods
20-03-2009, 21:52
I hope it sounds as good as you hoped!

symon
20-03-2009, 21:58
Yes it does. I need to get used it, let the cables settle down, and then get the Lenco working

symon
21-03-2009, 00:03
While I'm thinking about it, and this thread is still live, what should I be looking for to match with these beauties?
I have a Lenco to fix, so the turntable is sorted. What cd players go well with the Quads? And what about speakers?
Let's say that my budget would be up to £150 per item (ie, I'd buy them one at a time over the course of this year hopefully), and I don't mind buying second hand.
For comparison, I currently have some Acoustic Energy speakers which sound quite nice to me.

spendorman
21-03-2009, 10:27
Can't answer about the ancillary equipment, but if it was my 405, I'd swap the op amps in it for TL071, very cheap, will give the biggest value upgrade that I can imagine.

symon
21-03-2009, 11:56
Yep, that's already on my list of things to look at. Thanks

Spectral Morn
21-03-2009, 15:21
Hi Guys

Do you know the one thing, that stands out about AOS over many other places;), is the help offered by members to others. To all of those who helped Symon (and I am sorry I could not), I just want to say on behalf of AOS...Thank you. To you Spendorman ....:youtheman: Well done. :mex:

Symon... Glad its working for you now.


Regards D S D L----Neil :)

symon
21-03-2009, 18:33
Indeed Neil! A big thank you to all who had the patience to take me through what, in the end, was a simple problem. I've learnt a lot already through the help and encouragement offered.

Many, many thanks
Peter

Marco
21-03-2009, 18:53
Great result, Peter :)

Sorry I couldn't help on this particular one, as I have next to no experience with Quad gear, but I knew there were others around who would be able to provide you with the assistance you needed, so well done to Spendorman and others.

I'm quite proud of the wealth of experience in many areas and the friendliness and willingness to help others we have on the forum. Top stuff, people! :cool:

Marco.

symon
23-03-2009, 00:35
Sadly, more help is required!!

Yesterday, I had full and lovely stereo for both CD and vinyl. Today, I have an unbalanced sound, favouring the right channel, with the left channel there but very very quiet, for both CD and vinyl. What could have happened? Nothing about the set up has changed between today and yesterday. All the cables and leads are connected firmly and securely.

Any thoughts, clues hints as to what is wrong and how I might go about fixing it?

spendorman
23-03-2009, 10:43
Eliminate the 33 by going straight into the 405 with your CD player or some other input.

That is one easy step.

Those Din leads can play up, corrosion giving bad connection.

symon
23-03-2009, 11:35
Ok, that will be my first move. Drag out the old amp and use it as a pre-amp instead of the 33.
I did notice this morning that I had left one of the mono switches on whilst playing some vinyl. So, I need to double check that tonight.

symon
24-03-2009, 20:17
Quick update. The left channel comes in when the volume is turned up enough - just overr 2 for CD. I did notice today that there is a fizzing sound in the left speaker - with everything off apart from the 405. I need to check again, but I'm sure I've heard it before.

Beechwoods
24-03-2009, 21:02
The 33 does have a sweet spot on the volume pot - just over 2 (at least mine does). You listen to your stuff quietly, like me :)

I'm using a pair of Primalsea's -14db inline-RCA attenuators on the CD input. This lets me wind the volume up a bit on the 33, and gives me more control at lower levels. You might want to PM Paul (Primalsea) and see if he's got any these left. They're about the size of an RCA plug gender changer, and go between the end of the RCA from your CDP into your pre-amp RCA sockets (or DIN to Phono sockets).

The fizzing... not sure what that is. Does it happen with all the inputs to the 405 unplugged?

symon
24-03-2009, 21:20
Ah, cool. I thought it might just be a quirk of the gear. And, yes, just over two is where the proper sound kicks in.

I need to fiddle/listen a bit more to work out what is happening with the fizzing sound.

spendorman
26-03-2009, 18:50
Unfortunately, the Quad 33 volume control does not have very good balance at lower settings. There is often slop in the linkage of the two channels. This is made even worse if the input to the 33 is a bit high, say from a CD player or tuner (other than Quad tuners that have a low output).

Dave Cawley
26-03-2009, 18:54
Come on guys, this is obviously a dirty volume control. Clean it with some switch cleaner and live in harmony for another 25 years!! :kiss:

:bag:

Dave

Dave Cawley
01-04-2009, 10:09
Hi Peter

The volume control has a small slider that moves over a carbon track. This will wear and get dirty. Especially where it has been used the most often. You may get away with cleaning it by squirting into the edge of the control (you should be able to see the slider rotating it you look sideways into it whilst moving the knob). Or if it has finally worn out, it will need replacing.

You can get this from CPC or eBay http://cpc.farnell.com/servisol/100001300-200ml/super-10-switch-super-10-200ml/dp/SASERVISOL?_requestid=46980 :kiss:

If you are struggling to understand this, then you need to leave it to an expert. But make sure the expert really is an expert first!!

:bag:

Regards

Dave

symon
01-04-2009, 19:25
Is it possible to make my own switch cleaner? If yes, what with?

Thanks
Peter

Dave Cawley
01-04-2009, 21:39
No

symon
01-04-2009, 21:46
Fair enough.:cool:

Beechwoods
01-04-2009, 21:52
Stupid question. Is Switch Cleaner ok for potentiometers (volume controls)? I seem to recall reading somewhere that the carbon tracks on pots could be dissolved really easily by some switch cleaners, and that a special cleaner was needed for them :confused:

Dave Cawley
02-04-2009, 06:59
I would not have recommended it if that was so!
___________________
Electrical contact cleaner and lubricant
Ideal for cleaning crossfaders and pitch controls
Non-flammable formulation
Extension tube for hard to reach places
200ml can

Servisol electrical contact cleaner and lubricant in a can - ideal for cleaning your crossfader or pitch controls. Supplied complete with an extension nozzle in a 200ml can.

_______________

Switch and contact cleaning lubricant. Quickly removes tarnish and other deposits. Residual lubrication film protects contact surfaces. Prevents arcing between dry contacts. Safe to use on plastics, rubber and other delicate materials

Beechwoods
02-04-2009, 08:10
I know you wouldn't Dave. The important bit I guess is to get one that is specifically recommended for volume controls and faders. I've heard sad tales about Deoxit and volume controls for example. Where can you get the one you mention?

Dave Cawley
02-04-2009, 08:12
Where can you get the one you mention?

See my post 176.

Dave

Marco
02-04-2009, 08:23
You can also get that stuff in Maplins :)

Marco.

Tom472
02-04-2009, 16:07
I'd say the humming or fizzing is most likely to be the PS elecrolytics in the 405. They're absolutely massive, and no matter who "services" it, they wouldn't have replaced these as they're expensive.
Once you've got it all working you're probably going to have to replace them as they'll be affecting the sound of the amp as well as the annoying hum. I think mine cost me about £30.
Like others have said, the 405 needs some tweaking to get the best from it, there's a great web article on modifying the 405 somewhere by a German guy I think - but there are companies who will do the work if you're not confident doing it yourself.

Hope you get it all sorted.
Tom

DSJR
02-04-2009, 17:55
The supply caps in a 405 lasted around eleven years of fairly light use before they started to leak. they're not that big in value by supply cap standards and are fairly inexpensive to replace. You have to be good at soldering though...

I'd also recommend looking at the Dada website, as they have a dual supply board that is pretty well a drop-in replacement for the caps that come out (caps have tripled in value for the same physical size, making this possible nowadays).

Other sources of buzzing could be if phono sockets have been placed instead of the DIN (there are two holes nearby that many people have used. You may have a hum loop and Quad used to supply a two core mains lead to connect the 405 series to their preamps as I recall. Purchased IEC replacements with moulded plugs will have all three mains connectors wired, thus causing an earth loop......

The 33 volume pot is possibly the weakest part of it and I think Quad had some new ones made with integral mains switch. We used both switch cleaning solvent (from RS) and, also, Servisol cleaner/lubricant, which may be better for very old carbon track pots and pre-sets (this latter was used extensively in TV workshops where TV's had the cheapest, lowest of the low standard of components fitted).

spendorman
03-04-2009, 12:08
There have been switch cleaners that are just that and do not provide a lubricant. These are not usually good to use on potentiometer (found out the hard way many many years ago). Switch cleaner/ lubricant is generally OK.

Again, I would say eliminate the 33 by feeding the 405 direct fron CD payer etc. to find out if its the 33 or 405 at fault. Take it from there.

Have a look at the top of those two big capacitor cans in the 405. Can you see them leaking, are the tops bulging?

If on a budget there are other suppliers than Dada and Net Audio of those big caps. Check on e bay. Dada and Net supply good stuff, but one can find cheaper and still acceptable capacitors.

Tom472
03-04-2009, 13:26
I'd agree with the above - the Dada board looks good, but you could buy two of those 15,000uF BHC capacitors from RS for £30 or so. Depending on what you spent on your 405 and how handy you are with a soldering iron will probably determine the best course.
But definitely try the 405 and the 33 in different set ups first to determine which is at fault.

Tom

spendorman
03-04-2009, 13:55
I'd agree with the above - the Dada board looks good, but you could buy two of those 15,000uF BHC capacitors from RS for £30 or so. Depending on what you spent on your 405 and how handy you are with a soldering iron will probably determine the best course.
But definitely try the 405 and the 33 in different set ups first to determine which is at fault.

Tom

There are some new Vishay BC Components Capacitors that are suitable on e bay at about £15 including postage at the moment. (I have no assosiation with that sale of course).

Tom472
03-04-2009, 14:53
There are some new Vishay BC Components Capacitors that are suitable on e bay at about £15 including postage at the moment. (I have no assosiation with that sale of course).

Looks like a good deal, and at least you know they're defo going to fit. Only 10mF rather than 15mF and double the ESR I believe for those caps as compared to the BHC's though.

Tom

spendorman
03-04-2009, 15:07
There are some new Vishay BC Components Capacitors that are suitable on e bay at about £15 including postage at the moment. (I have no assosiation with that sale of course).

Looks like a good deal, and at least you know they're defo going to fit. Only 10mF rather than 15mF and double the ESR I believe for those caps as compared to the BHC's though.

Tom

Standard 405 has 10,000 uF capacitors so thats OK and I guess that their ESR is probably better that the original.

DSJR
03-04-2009, 15:26
I replaced the 7,000uF Mallory computer grade caps in my bridged Crowns with 22,000uF Visahay BHC's from Farnell (I don't have a trade account and over £20 is free postage). No turn on surges that I can see and no other troubles at all. The Crowns are so carefully VI limited all over (due to their cold running role in studios) that any sonic advantage in these caps is probably well hidden. The Quad 405 with mk2 current limiting or Dada replacement boards may be more able to justify the expense, although £12 - £15 each or so isn't expensive IMO for low ESR ones.