Quad II Rebuild and Upgrade - Start to Finish

A rebuild with higher spec components and modern safety requirements. Not a restoration!

[@jimmyvthejedi]

awesome ... always amazed by the skills of passionate people ... really great work !

[@n4s117]

A very nice quality rebuild. I had mine done about 8 or 9 years ago. I've had the Quad IIs since 1972 and they're in use daily with my ESL57s.

[@beslemeto]

I can buy them for £850.Do you think it's worth it?

[@marksntl7632]

Nice one Pete! That took quite a bit of work, Percy Verance and dedication to do that mate! 10 out 10 for that mate! My Bro-in-law purchased that exact same setup you have there with same pre-amp etc back in 1998. The only difference was he had some Mordaunt-Short speakers at the time. He was very lucky though... The Quad II's were in Mint condition at the time and needed no work doing to them... The Quad pre-amp etc, he purchased from new and were still in Mint condition... The system sounded like magic. I will never forget that... Keep going mate. Look forward to the next update...

[@theoldgit9884]

Thanks Mark!

[@russputin6294]

Absolutely fabulous. this puts the whole recycling / environmental issue into perspective when properly manufactured seventy year old gear can be renovated back to practically (or in terms of the component and connector upgrades better than) new condition and still return a state of the art performance. Contrast this with modern mass-manufactured and "disposable"equipment with associated rapidly obsolescent (and by definition irreplaceable) microchips and sealed casings. An absolute joy to watch and no doubt these will be handed down to the next generation for another seventy years of thrilling performance

[@theoldgit9884]

Thanks for your kind comments Russ, much appreciated!

[@RanaSarkar-gq5xp]

Wonderful work. Love to own a pair of Quad 11. Currently using Leak ST20 which is great. Would like to contact "Oldgit" for advice. Do you have a contactable email? Regards Rana

[@eric-g-rose]

Being a Quad user for decades I love your videos. One of my 405's needs work so will be digging into it soon.

[@theoldgit9884]

Thanks Eric, good luck!

[@JamieBulloch1]

this is meticulous craft and so watchable, love it, love it....,

[@willeyex]

What an amazing video. Please make more videos, your methodical way is great and be interested to learn more from you

[@theoldgit9884]

Thanks Tom!

[@tweakerman]

Lovely Job, you should be very proud of the work you've done👍

[@theoldgit9884]

Thanks Tweaker man!

[@timoleary5815]

That was an absolute joy to watch, great to see old HiFi brought back for a new life. Beautiful work too, thanks for sharing from another old git!

[@theoldgit9884]

Cheers Tim. Happy New Year!

[@barrythompson]

Better than when new, top quality work, wish my dad was still alive to have watched this , he had the full quad valve set up in the 60s inc the tuners, fm with the added multiplex decoder for stereo and a med short short am tuner. Those 15 wqtts each amp seemed plenty powerful enough at the time with 12 inch Goodmans speakers.

[@theoldgit9884]

Thanks Barry, glad it may have brought back some happy memories.

[@davislanis6065]

Very nice work!! More than just cosmetic, real refurbishing!

[@yyams]

Very useful video... thanks. I was gifted a pair of these (along with the accompanying preamp & tuner) by a member of a ski forum last year, it was his first proper system and even though I'd never met the chap outside of chatting about hifi online he wanted to pass them on to someone who would use them. A wondrous act of generosity. The itch to delve into a refurbishment and modernisation is getting strong now, so it's good to find a video like this. I'm looking forward to seeing if they hold their own in the modern world of hifi. J James.

[@theoldgit9884]

Generous indeed. I'm sure they would acquit themselves very well, and probably exceed your expectations when compared to modern amps. They will need checking over of course. Good luck!

[@yyams]

​@@theoldgit9884 Ta, it's always nice when a youtuber takes the time to reply to comments. I'm glad to hear that half a century ish later they still have a place in hifi. And... Yep, a quick peek inside the chassis when I first got them confirmed they'll need more than just checking over. A very basic multimeter/visual scan over them suggests I'm going to have to replace the lions share of components. I suspect the view count on this video will skyrocket when I finally get moving on recommissioning 'em:D

[@ambrusnemes4847]

Very thorough and impressive work! I've just finished replacing some components of some recently acquired QII+22s, and this video tour was a real treat for me!

[@theoldgit9884]

Thanks Ambrus, I'd be interested in your progress.

[@ambrusnemes4847]

@@theoldgit9884 I've attached a link, but KZbin's deleted it. It's on a DIY forum. I mainly swapped the caps only in all the three units to PP and electrolytics.I left the original resistors in place, as they are thankfully mostly within tolerancy .

[@sverkergrahn9475]

Thanks for this lesson, just what I needed to get going with my pair of Quads! Glad to see that GZ34, that I have, is ok so I don’t have to search for GZ32 which don’t seem too easy to find. The path is clear 😊

[@theoldgit9884]

Thanks for your comments, good luck with the project!

[@jeremycosmodavies]

A beautiful piece of clear, informative instruction on a quality piece of kit. It Wouk be great to see you take on a similar challenge with a Quad 303 Power Amplifier. Many thanks.

[@theoldgit9884]

Thanks Jeremy!

[@max79444]

Absolutely first class work on the Valve Quads.

[@patryk2700]

Unique insight into a splendid piece of work, thank you for sharing!

[@theoldgit9884]

Thanks Patryk!

[@SuperMYSHKIN]

Fascinating, I would trust you with my Audio note.

[@juliansleath1989]

Great work - thanks so much for sharing with us.

[@jetblakink]

Excellent work!… 😎

[@theoldgit9884]

@jetblakink Thanks!

[@allanpowell7208]

Hi old git, I have only just come across this, your videos are always welcome, interesting and entertaining. Consider doing more Cheers

[@theoldgit9884]

Thanks for your kind comments Allan. Hoping to do another one soon!

[@claretlover1]

Superb, I wish I had your patience and dedication. Glad you are a Genesis fan!

[@theoldgit9884]

Thanks claretlover1!

[@gavbansal967]

Excellent, glad that you're back.

[@theoldgit9884]

Thanks Gav!

[@eddyaudio]

A great refurbishment Peter full Marks Mate and Greeting from Australia Regards Ian,

[@theoldgit9884]

Thanks Ian!

[@justicelut]

Beautiful restoration. Well done!

[@bryanmcwhirter9945]

This was excellent. I have a pair of monoblocks and the matching stereo pre amp which I've yet to rebuild alonf with the original owner's manual which has the schematic. As yours, mine needs a complete rebuild and new paint but the badges are in good shape but i have the 220 v model so I'll just use a step up transformer. Thankyou! Bryan from Canada

[@theoldgit9884]

Thanks for your comments Bryan, good luck with your project, I'd be interested in your progress.

[@grahamkent2868]

A really enjojayable video, great workmanship!

[@theoldgit9884]

Thanks Graham!

[@henrikl1394]

Quad IIs sounds really nice my brother in law have a pair. But he is using big horns , so don't need many watts there 😛

[@osbert43]

Fantastic to watch this!! Makes me want to get out my Quad II's for a listen. I love the sound they deliver (your playing Genesis and Vaughan Williams...those are my choice selections, made me smile) but they have been shelved for now, usurped by a Radford STA25. I have the ESL 57's...and they deliver musical bliss. And on standby, ready to play in a moments notice, my trusty Quad 303. Thank you for this video!

[@theoldgit9884]

Thanks for your comments Rob, I'd like to get my hands on STA25!

[@Radfordperson]

@@theoldgit9884 Worth getting one, mine's a Mk3, also have Quad II's, 303, 405-2, ESL63's and 57's, almost forgot, I still have a mono Williamson, made at Rogers in the early days.

[@theoldgit9884]

@@Radfordperson I'll keep looking! Cheers.

[@Radfordperson]

@@theoldgit9884 Radford Revival produce new ones and are great people. My STA25 Mk3 I bought second hand well over 40 years ago, no parts have been replaced in this time, and they all look original.

[@beslemeto]

Which one of them sounds the best?

[@chancowboy7263]

Very nice. I have a pair of Quad II which is needs to be rebuild and/or restoration.

[@smsshafic]

Excellent job. Very informative. Thanks.

[@theoldgit9884]

Thankyou!

[@joe1569]

Fantastic restoration

[@theoldgit9884]

Cheers Joe!

[@jimmiwestpedersen359]

Wow….nice work…like new again👍 wish i could work with that…👍save a lot of money

[@hksunchaser1]

great rebuilt!

[@izzzzzz6]

Fantastic work. Great set of Skills! Could i just use a fridge starting or motor starting style capacitor as the smoothing cap?

[@mohammadnaeemjaved1826]

Very nicely done the rebuild and upgrades congrates. Can you show in the circuit diagram the three modification that you have done. Thanks.

[@fernandocabello2876]

Congratulations for the great good job!

[@theoldgit9884]

Thanks Fernando!

[@robertjc605]

Great video 👍

[@chrisvinicombe9947]

Quality work they look great 😀 oh and welcome back to the youtube.

[@theoldgit9884]

Cheers Chris!

[@FromBrlyn]

Super video - very informative and interesting for that. Didn't you have a video of a Quad 303 repair? Can't find it anywhere.

[@theoldgit9884]

Hi, I took it down to make some changes, but haven't got round to it unfortunately. If you email me at [e-mail] I can send a link.

[@rickwhitehill1801]

Brilliant MrD

[@theoldgit9884]

Thanks Rick!

[@gregwilliams2746]

Loved this video so much I've watched it a few times, already! Lovely job! I'm curious, what made you decide to rewire rather than reuse the old loom?

[@theoldgit9884]

Hi Greg, thanks for your kind comments. Valve bases were a bit manky so I decided to change them all, this meant desoldering from the loom with the attendant problems of 60 year old wiring. So rewired with a better gauge and kept old loom for pos future use. Cheers.

[@johnlake6321]

Great job!!!

[@lawrencemoran8255]

I’d be interested to see more of your work on the 34 preamp; might a video be in the works??

[@scrumpymanjack]

Really interesting. Thanks.

[@theoldgit9884]

Thankyou!

[@mymodel6]

Pleeeaaase do the comparison! :) We have two Quad 2's, two 303's and two of the Leak amps all need restoring :)

[@itsonlyme9938]

I wounder if you could use 4.7uf 630v polyester caps the down side would be having to use 4 of them to to make up 16 uf but the esr would be nearly zero.

[@theoldgit9884]

Thanks, I suppose this could be done, but not sure why?

[@iainmeikle3616]

Nice job.

[@matthewtaylor7355]

Dear OG..... What do the restored Quads sound like?? .... All new may sound different

[@newtronix]

Very nice job! Not sure about the mains switches though.

[@dab9742]

At 16:08 you mount a 50+50uF capacitor on a GZ32, aren't you afraid of fatiguing it prematurely ? 19:20 For the 33pF capacitor before C2 and C3, the insulation defect of the original capacitor, added before, but also after C2 and C3 a slight capacitance to ground, is this necessary ? 18:30 Why didn't you mount the power supply socket as close as possible to the input terminals of the power supply transformer, that would be a plus, wouldn't it ? Thanks for this restoration video, well done for the work, and saving a copy of this magical little amp ! 😉

[@theoldgit9884]

Hi, Thanks for your interest. Regarding the 50+50. This initially concerned me, however these values are within the spec of the GZ32, and especially since the amp consumes only around 200mA. My ultimate intention was to fit GZ34's which are better all round. The original metal body of C2 & C3, together with the Quad clamping arrangement work together to shape the response. I used plastic bodied devices with no clamp. The 33pf is an official Quad modification in this situation. Power supply socket was located purely for domestic aesthetic reasons. I didn't want cables at each end. Cheers!

[@dab9742]

@@theoldgit9884 Hello, Thank you for your clarifications. As far as the GZ34 tube is concerned, it does perform better and heats up less, but what bothers me is that the shape of the bulb isn't as pretty as that of the GZ32! Regards !

[@theoldgit9884]

@@dab9742 Completely agree. I'm still using the 32's!

[@cortefinoibiza]

Hi Pete! I will get my hands on a pair of Quad II soon but they are not coming with the Quad Control Pre-Amplifier. My idea was to adapt the amplifier to be able to connect my Marantz 1060 pre amplifier outputs to the Quad II Amplifier Inputs. Should I installed that 470uF capacitor on the Quad II inputs? Thanks for sharing your experience, I really enjoying watching your videos, it is inspiring!

[@theoldgit9884]

Hi, if you're using a different preamp for safety it's best to use a capacitor at the input. I initially used 470nf but the math suggest 0.1uf is better. You can check frequency response on the finished unit and adjust the value accordingly. Cheers.

[@francescodali224]

hi..for the restoration I would not replace all the original components, what a high level gift, but I would limit myself to only the faulty ones. For example, the original carya and oil capacitors are of the highest quality and it is difficult to find them at a loss. Then they also determine the sound quality of the quads, the conservative rest is undoubtedly the least to not alter the musical qualities of these exceptional amplifiers .

[@orsettcock]

Fantastic work. I need a Quad Point one pre amp renovated. To go with my Leak 20 and quad ESL57 speakers. Also do you sell renovated Quad equipment?

[@theoldgit9884]

Hi James, thanks for your comments. I don't do repairs or sell stuff, just a hobby for me really.

[@malcolmnzable]

Love your work, just starting on my rebuild, do you have a schematic for the mods?

[@Resorob]

Hi Peter, like you I once purchased the Douk 300B SE PCB with parts, never got around to building it. You had an awesome video up showing the build and issues you encountered. Can it still be seen somewhere and is it at all worth building? Kind regards, Rob.

[@theoldgit9884]

Hi Rob, thanks for your comments. Yes I still have the video, I can send you a link if you email me: [e-mail] Cheers.

[@budekins7779]

What speakers are you using in the living room?

[@theoldgit9884]

They're Samba kit speakers from Soundimports.eu in Europe

[@bernardstokes6550]

Very informative and useful. One question and perhaps I now the answer ( slight changes to the circuit) why did you not use the original wiring loom?

[@theoldgit9884]

Thanks Bernard, you're right, it was a bit impractical with the layout changes, plus the original wiring itself left a lot to be desired. However I will reuse the loom and the main electrolytics on another project which is a full restoration (as opposed to modern rebuild). Cheers.

[@sonicstep]

I've known about these valve amps being modified and matching period AM tuners converted to FM. How much modification is acceptable till say one of those amps is no longer considered a Quad 2.? Where does one draw the line? Personally, if those capacitors are good, I wouldn't change them for modern ones. Just leave them as is.

[@reneq.congmon8083]

I was empress of the work you put in it. So nice, very nice. Is your shop in USA please? or UK? Do you accept from other country for rebuild and upgrade please? Thanks you so much.

[@theoldgit9884]

Thanks for your kind comments Rene, I'm in the UK. Unfortunately I don't have time to undertake rebuilds or repairs. Rgds.

[@intrentnet]

Did you change the output impedance? I’m thinking of modding mine with a switch so I can go from the stock 15 ohm to 7 ohm easily. I’m currently planning to use them with an 8 ohm speaker but hope to get ESL 57’s in the future. From what I’ve been able to find it’s a matter of snipping the jumper from R to S and adding jumpers from Q to R and S to T. Is that what you did?

[@theoldgit9884]

Yes, that's correct. It's possible to go down to 4 ohms if required by removing all connections to T, S & R and wiring speaker output directly to Q. Cheers.

[@nickkip459]

Great bit of work very nice to watch. I would still love you to work on my 33 to put a remote on it. Strange one don’t know if you would have any idea but when I increase the treble on it only works on one side. If I change the amp boards over follows the issue I can’t see anything wrong spent ages with multimeters but know it’s on those boards 🤣🤣

[@theoldgit9884]

Hi Nick, it's difficult to do long distance diagnostics, but if the fault moves to the other channel when you swap boards I would spend some time doing some comparison checks, particularly on the capacitors - they may be difficult to check reliably with a standard multimeter, so might be best just to change them all.

[@simonbartlett8252]

Thanks Pete - so so useful and the finish you achieve is fantastic. I have just got my hands on (I believe) an original pair of quad ii's - both in need of basic rebuild/ upgrade. I did see a 500mA fuse inside the ones you did which is missing from the pair I have. Is this protection for the PT in case of O/P valve failure? I have a few other questions - would you mind if I sent them your way.

[@theoldgit9884]

Hi Simon, Thanks for comments. I'll try and help if I can.

[@simonbartlett8252]

@@theoldgit9884 Thanks Pete - I have sent an email.

[@hiveofactivitysussex6924]

Very good rebuild! Thoroughly enjoyed you video. Which speakers do you have in your lounge system?

[@theoldgit9884]

Thanks, they're 'Samba' kits from Soundimports in Europe or Parts Express in the US. I really like them.

[@eslhifisweden4595]

Nice! How did you set the potentiometer in Quad 34 to set output level between 0,5 and 1,5volts? Im interested in doing the same mod but what I see you need to change 4 resistors to go up. Grateful for any help.

[@theoldgit9884]

Hi, Please email me and I'll see if I can dig out the info. [e-mail]

[@ChrisLewis-x9l]

I would like to contact you but can’t seem to find a route. Can help

[@lukaszbigaj878]

How can i contact you. I got some stuff that i need serviced. Kind regards Lukasz

[@greenlanternseven]

Hello good sir, I too am restoring my Quad 2's right now and I require a Quad badge or restoration can you tell me where you had your badges done for replacement? ..thank you kindly, also I need a volume dial for my Quad 22 pre amp and was hoping you knew of a Co.

[@theoldgit9884]

Hi Scott, contact Jon at [e-mail] for the badges. He should still have the artwork and measurements, but make sure you measure the screwhole positions (mine were slightly out, my fault). It may best to send him a badge. Quad UK may be able to provide volume knob, they still carry extensive spares. Cheers.

[@greenlanternseven]

Thank you very much sir I appreciate your help

[@MrJorisC]

Hi, why aren’t your Quad 33 & 303 vids no longer online?

[@theoldgit9884]

Hi, I took them down to do some additional editing, but other things got in the way! I can send you a link to the originals if you're still interested, email [e-mail] Cheers.

[@julianbrearley6798]

Great video Pete. I have several Quad systems and my Quad II's are currently off with Rob at Audiolabs at the moment as rebuilding them is beyond my capabilities. I have a couple of questions, both of which you seem to have solved in this rebuild - I also have the 'broken perspex badges', who did you get to build new ones as I can't find anyone I trust to do that, the second is colour - did you ever manage to pin down a RAL number for these units? I realise that the colours were less than completely consistent over the many years of production and mine will have faded over 65 years but I'd like to get as close as possible.... I'm looking forward to trying my Quad II's with my 34 but would suggest not writing off their use with an original 22 unit. Rob rebuilt my original 22 for me and did some power and RCA socket mods,. He sent me scope images of the remarkably low measured THD and the flat response that a 22 can manage when it's working properly. When coupled to my original ESL 57's and choosing 'music to suit' it sounds as good as anything I've ever heard....

[@theoldgit9884]

Thanks Julian, contact Jon at [e-mail] for the badges. He should still have the artwork and measurements, but make sure you measure the screwhole positions (mine were slightly out, my fault). It may best to send him a badge. WRT colour I have no data unfortunately, the sample was accurately matched at a motor paint factor. Cheers.

[@moodyga40]

Been waiting for a video i thought these blocks had kt66 in them

[@theoldgit9884]

They do!

[@MatthewSparkes]

These aren't for sale, by any chance?

[@theoldgit9884]

Hi Matthew, Our house is getting cluttered with projects, so might be tempted!

[@MrDuodecar]

HI, do you know the value in henry of the L1 choke?

[@theoldgit9884]

Yes it's 20H

[@MrDuodecar]

@@theoldgit9884 Thank you!

[@NatSteeleMusic]

ESL57s next..?

[@theoldgit9884]

Cheers Nat, I'll start saving....

[@davidbrothers3903]

Hi Pete - do you do repairs to a Quad Tuner - how do I contact you ?

[@theoldgit9884]

Hi David I don't do repairs, but I can recommend Quad themselves who do a fixed price repair. Just contact their service dept via the contact page on their website.

[@simonmarsden66]

Hi Pete, do you take on outside work?

[@theoldgit9884]

Hi Simon, thanks for your interest but I don't really have the time or proper facilities to do additional work.

[@simonmarsden66]

@@theoldgit9884 in that case could you possibly take a photo of the capacitor mod and give the values, I need cooler valves, thank you

[@theoldgit9884]

@@simonmarsden66 email me [e-mail]

[@user-Stefan_Ulli]

Soviet capacitors K42У-2 are very bad in the interstage of the amplifier !! The best Soviet capacitors in the interstage are K40У-9, K73-16, K78-2 ...

[@ladronsiman1471]

DONT put a pcb board in there .,If it has lasted 65 years i t will probably last 10 times more

[@ronniemarker2898]

Hello Pete - lovely and very lucid and informative video - thanks ! Could I inquire with you IF you could repair-refurbish (to make electrically safe, stable and reliable - for daily, present-day use) a pair of circa 1953~1955 Quad IIs that I have ? If so, could I request your email contact or even a phone number, please ? Many thanks and all best wishes - Ronnie Marker (Mumbai, INDIA)

[@theoldgit9884]

Hi Ronnie, sorry for delay in reply. In your case I would suggest sending the units to Quad themselves. Their service is very good and they still support their vintage equipment. They can repair, service, safety check and ensure they are operating to original spec. They are part of the IAS group now: quad-hifi.co.uk/pages/contact-us