View Full Version : Quad 33 help please
On deciding to try and get dad's old gear going I'm starting with the 33 first issue is i can't seem to get power. I have mains and the fuse is OK but it seems nothing at the psu, could someone tell me what voltage I should be getting and where please.
I'd like to repair it im pretty handy with a soldering iron and have built electronics kits before I dont know what components do but I can fit them.
Failing that any reccomendations on where or who to send it to I've tried contacting quad but as yet no joy.
31630
Dave
Update somehow it came to life! Maybe it was a dirty contact in the volume switch but who knows im happy it lives.
Im going to order a set of replacement boards for it off ebay there's a guy on there that's selling a set of new boards.
Dave.
That's good news Dave. :)
When you get around to replacing the PCBs, I would suggest you also clean all switches and potentiometer with an aerosol switch cleaner. You won't be able to clean the mains switch on the back of the volume control, but a few "on and off" switch turns won't do any harm.
Let us know how you get on.
Hello,
Why would you need new boards? What’s wrong with the old ones?
A link to the eBay seller? Ferndale?
Hello,
Why would you need new boards? What’s wrong with the old ones?
A link to the eBay seller? Ferndale?
My dad told me one of the channels wasn't working I know the large pcb that plugs into the back has one edge snapped so it could be that?.
I have ordered some bits to convert the sme tonearm to rca sockets which doesn't look a hard job then I can fit the arm to the turntable so I need to find out how to set that up the sme protractor seem a bit steep at £10 for what looks like a piece of paper.
Dave
Hi,
If tracks are broken then yes. Inspect the PCB, possibly post a photo of the damage.
Hi,
If tracks are broken then yes. Inspect the PCB, possibly post a photo of the damage.
Tracks definitely broken so its definitely worth replacing that one to start with?. Yes Ferndale on ebay.
Dave
No, just repair it. Superglue the two bakelite parts and solder bridges would in most cases suffice. A photo will tell what can be done.
No, just repair it. Superglue the two bakelite parts and solder bridges would in most cases suffice. A photo will tell what can be done.
I'll take a picture later and post it.
Dave
No, just repair it. Superglue the two bakelite parts and solder bridges would in most cases suffice. A photo will tell what can be done.
I could have a go at repairing it i assumed that as it had 4 sides the damaged one would be bypassed I guess not, would this be the broken channel my father mentioned?
31633
31634
Dave
Each side of the card corresponds to pick up cartridges having different sensitivities and requiring different equalisation. The damage affects three sides of the card, so the only side not affected is the one shown at the top.
Looking at an enlargement of the second photo it would appear that the circuitry corresponding to those sides to the left and to the right are undamaged, but I would have to see a much larger photo, and to see what cartridges they cater for (that is, to see the corner markings: C; or M1, and M2. Only the side which is unpopulated by components (and marked as S1) is damaged, but this side will now be used.
However this damaged side will make it difficult to insert the card, so a replacement is recommended; repair using superglue is unlikely to be a long-term fix, especially if the card is to unplugged and replugged several times.
Inspect the motherboard too. The broken board isn’t beyond repair anyway!
Inspect the motherboard too. The broken board isn’t beyond repair anyway!
Which one is the motherboard?.
Dave
The one that sits at the base of the preamp, that occupies the whole surface!
When fitted the square disc sensitivity card protrudes from the back of the preamp so it can be easily removed and reinserted with a different side if required. Looking at the damage it would appear that the preamp was dropped and that part of the disc selection card which protrudes has broken off.
The undamaged side (at the top of the photo) is for M1, corresponding to a fixed-magnet cartridge having a low output of 0.5 - 2.0 mV/cm/sec, which is typical of a good quality magnetic cartridge such as was used by the previous owner and one benefiting use in an SME arm. So since the side of the disc selection board is undamaged for such a cartridge it could easily be refitted when the cover of the Quad 33 is removed.
Whilst you have the cover of the preamp off to inspect the mother board, it might be a good idea to remove in turn the three vertical circuit boards that are plugged into the mother board, clean the respective multi-way connector with some aerosol switch cleaner and reinsert the board.
Thanks chaps I have a new pcb on its way to try.
Onto the next bit to sort is the tonearm I have ordered some bits to convert it to RCA plugs, but I need a new cartridge any reccomendations? I dont want anything to pricey as I dont want to damage it whilst I set it up.
Also which set up protractor do I need i see there are different types im fitting it to a TD160 B Mk2. The sme serial No.94692
31639
31640
31641
Dave
The 3200XE was a superb cartridge. I still use one on my B790.
Stick to AT. A VM95EN or ML if budget allows.
I would agree; try any of the Audio Technika cartridges as suggested by Jacques, they should not be too expensive.
Regarding the SME arm, since it looks to be an early model it might be designed to follow the Stephenson prescription to minimise the tracking error. Later versions were changed so as to require the Baerwald prescription to minimise the tracking error. You need to know the serial number (as marked on the underside of the bedplate): if less than 439606 the Sephenson prescription applies, if it is 439606 or greater use the Baerwald prescription.
I would agree; try any of the Audio Technika cartridges as suggested by Jacques, they should not be too expensive.
Regarding the SME arm, since it looks to be an early model it might be designed to follow the Stephenson prescription to minimise the tracking error. Later versions were changed so as to require the Baerwald prescription to minimise the tracking error. You need to know the serial number (as marked on the underside of the bedplate): if less than 439606 the Sephenson prescription applies, if it is 439606 or greater use the Baerwald prescription.
The serial is 94692 so I guess definitely the lower so the Stephenson prescription (no idea what that means so something else to google).
31642
Dave
Is the card alignment protractor missing?
If it is missing, I have a spare you can have. If you want it send me your address as a PM.
If it is missing, I have a spare you can have. If you want it send me your address as a PM.
I dont have and have sent a pm thank you.
Dave
I have the chance of a pair of Monitor MA6 speakers would these be suitable/good speakers?.
Dave
Yes they should be fine with the 303.
Pigmy Pony
30-10-2025, 17:38
I have the chance of a pair of Monitor MA6 speakers would these be suitable/good speakers?.
Dave
Get them snapped up David :)
MA always went the extra mile with their real wood veneers, so even ropey examples could be sanded and refinished. I like Monitor Audio's early speakers, I had a pair of their R352s in the 80s, and currently own some R852 MDs which aren't going anywhere any time soon.
Im about to convert the tonearm for RCA sockets the original SME plug has a separate ground wire that connects via the mounting screw on the socket to the tonearm then the black wire on the tonearm has a lug on the backside of that screw.
I have seen that I could solder the black to the green of the right channel to achieve the ground without needing a separate lead is that correct?.
Dave
Why can't you connect the black wire with its lug to one of the fixings of the plate that carries the RCA connectors? You will still need a connection from the arm base to the metalwork/earthing terminal on your amplifier.
How is the metalwork of your Thorens turntable earthed?
Why can't you connect the black wire with its lug to one of the fixings of the plate that carries the RCA connectors? You will still need a connection from the arm base to the metalwork/earthing terminal on your amplifier.
How is the metalwork of your Thorens turntable earthed?
The original sme plug has the earth incorporated so takes it from the arm metalwork to the turntable plate then turntable to amp.
So once the rca sockets are fitted I'll need to put an earth from the arm to the turntable base?.
Dave
Yes, and you will also need a separate connection between the arm base/turntable metalwork and your amplifier.
Yes, and you will also need a separate connection between the arm base/turntable metalwork and your amplifier.
Being a hifi imbecile can I just ask, as the green and blue both go back to earth on the amp why could I not go from the arm earth to either of those?.
Dave
Well you can, but it is always preferable to keep the safety earth separate from the audio signal return.
Well you can, but it is always preferable to keep the safety earth separate from the audio signal return.
OK that makes sense thank you.
Dave
This morning I changed the sockets on the tonearm to rca sockets rather than paying £40 for a kit I bought some sockets and made the other bits to suit.
31649
31650
Dave
I'm now trying to set up the arm so far all good apart from in the instructions I got off line my arm looks different the rod going through the balance weight doesn't have graduations to set it for the cartridge weight. Do I have the wrong instructions I got these off the sme site.
31651
31652
Dave
No, it was only the later SME 3000 series arms which had those graduations.
What you have to do is:
(1) Slide the secondary weight to the back of the weigh rod (as shown in your photos)
(2) Disable the bias weight (the very small weight on the nylon cord that passes through the 'fishing rod' on the left of the arm, by unhooking the nylon cord from the graduated rod at the top of the bearing housing).
(3) Counterbalance the cartridge fitted in the headshell, using the main counterbalance weight (the large one that slides on the arm extension behind the bearings), so the arm can 'see saw' when disturbed from the horizontal. Make sure the playing weight arm is horizontal before you lock the main counterweight in place.
(4) Apply the correct, or suggested, playing weight for you cartridge. (Each notch corresponds to 0.25g, though for complete accuracy you should use a set of stylus scales).
(5) Now this is the tricky bit: with the arm loosely retained in the arm rest, place the shaft of a narrow bladed screwdriver, or something similar, underneath the arm just behind the bearings and lift the entire arm off the knife edge bearings.
(6) If the headshell and cartridge 'droops' anti-clockwise as seen from the front, the counterbalance weigh-rod need to be moved out from the main arm. Move it sufficiently far so the headshell doesn't droop at all.
(7) Lock the weigh-rod in place with the vertical Allen screw on the main counterweight.
(8) Now apply the anti-skating or bias weight be re-hooking the nylon weigh over the graduated rod attached to bearing housing. Again each notch corresponds to 0.25g. SME will tell you that the anti-skating force should be equal or similar to the playing weigh. That might have been true in the past for cartridges having a conical stylus, but in my experience the anti-skating force needs only to be one half to two thirds of the playing weight with cartridges hav ing an elliptical stylus or better.
(9) Finally arrange the bias weight 'fishing rod' so that when the stylus is resting in the record groove at the start of the record, the nylon cord is at right angles to the graduated rod when viewed from the top.
The next stage of setting up the arm involves using the alignment protractor I sent you. With the protractor place over the central spigot of the turntable and the stylus placed in the pin hole of the protractor, the sides of the headshell must be exactly parallel to the thick black lines. Move the whole of the arm either forward or back so as to achieve this condition. Lock the arm in place, remembering to ensure that condition (9) above is maintained.
Thanks Barry I did find the correct instructions on Sme's website but yours are a bit more detailed. I have ordered some scales i do have some to weigh the grain of rifle pellets but thought ones made for the job would be better.
On the plus side I fired up the amps and tuner last night and it worked both speakers (channels?) Worked so i assume they will work when the turntable is plugged in.
Thanks for the help thus far.
Dave
No, it was only the later SME 3000 series arms which had those graduations.
What you have to do is:
(1) Slide the secondary weight to the back of the weigh rod (as shown in your photos)
(2) Disable the bias weight (the very small weight on the nylon cord that passes through the 'fishing rod' on the left of the arm, by unhooking the nylon cord from the graduated rod at the top of the bearing housing).
(3) Counterbalance the cartridge fitted in the headshell, using the main counterbalance weight (the large one that slides on the arm extension behind the bearings), so the arm can 'see saw' when disturbed from the horizontal. Make sure the playing weight arm is horizontal before you lock the main counterweight in place.
(4) Apply the correct, or suggested, playing weight for you cartridge. (Each notch corresponds to 0.25g, though for complete accuracy you should use a set of stylus scales).
(5) Now this is the tricky bit: with the arm loosely retained in the arm rest, place the shaft of a narrow bladed screwdriver, or something similar, underneath the arm just behind the bearings and lift the entire arm off the knife edge bearings.
(6) If the headshell and cartridge 'droops' anti-clockwise as seen from the front, the counterbalance weigh-rod need to be moved out from the main arm. Move it sufficiently far so the headshell doesn't droop at all.
(7) Lock the weigh-rod in place with the vertical Allen screw on the main counterweight.
(8) Now apply the anti-skating or bias weight be re-hooking the nylon weigh over the graduated rod attached to bearing housing. Again each notch corresponds to 0.25g. SME will tell you that the anti-skating force should be equal or similar to the playing weigh. That might have been true in the past for cartridges having a conical stylus, but in my experience the anti-skating force needs only to be one half to two thirds of the playing weight with cartridges hav ing an elliptical stylus or better.
(9) Finally arrange the bias weight 'fishing rod' so that when the stylus is resting in the record groove at the start of the record, the nylon cord is at right angles to the graduated rod when viewed from the top.
The next stage of setting up the arm involves using the alignment protractor I sent you. With the protractor place over the central spigot of the turntable and the stylus placed in the pin hole of the protractor, the sides of the headshell must be exactly parallel to the thick black lines. Move the whole of the arm either forward or back so as to achieve this condition. Lock the arm in place, remembering to ensure that condition (9) above is maintained.
I have tried moving the balance weight but it seems to be attached to a piece of rubber that doesn't allow it to slide.
Belay that it was just a little tight.
Dave
The arms all set up ready to go i just need the belt to arrive and I can try it out.
Dave
Looking forward to the next instalment Dave! Turntable setup seems a bit of a dark art but really it’s just following a logical process which it looks like you’ve done so fingers crossed for the end result!
Well this afternoon the drivebelt arrived i popped that on plugged everything in chose a record (Big Mama Thornton) and.... it all worked!! First time since the late 80s I think, thanks for all the help and advice im so happy dad's system is back working i just wish he hadn't binned the Thorens 125.
I'm sure there'll be more questions as time goes on but for now im going to enjoy listening to it. I'll build a new plinth but that's easy enough.
Thanks so much again
Dave
Wonderful! Hope you continue to enjoy it.
Well this afternoon the drivebelt arrived i popped that on plugged everything in chose a record (Big Mama Thornton) and.... it all worked!! First time since the late 80s I think, thanks for all the help and advice im so happy dad's system is back working i just wish he hadn't binned the Thorens 125.
I'm sure there'll be more questions as time goes on but for now im going to enjoy listening to it. I'll build a new plinth but that's easy enough.
Thanks so much again
Dave
Well done Dave. Glad to hear you got there in the end. Enjoy! :)
Great to read Dave, well done! Now enjoy the music. :)
nutteronthebus
10-11-2025, 10:28
have a look at this doc from DADA (now closed due to retirement ) https://web.archive.org/web/20231217105816/https://www.dadaelectronics.eu/uploads/downloads/01_Dada-Electronics-Revision-Upgrade-Manuals/Quad_33_Revision_V2.8.pdf
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