Quad 33 Pre Amplifier

Quad 33 Pre Amplifier


The Quad 33 Pre Amplifier is a classic example of British hi-fi at it's very best. First launched in 1967 to partner the Quad 303 Power Amplifier, the Quad 33 Pre Amplifier is a very high quality well designed pre amp using high quality push switches to select the input source which then passed through tone filters and a volume control before the sound is outputted to the power amplifier.

Although nearly 40 years old, it is still a very popular and flexible design, the disc input section (phono) for example is a moving magnet type with a four way selector card at the back which allows input sensitivity to be adjusted to suit the cartridge more closer as well as providing the option of feeding a CD source through the Quad 33.

One very good thing about the design of the Quad 33 Pre Amplifier is that it is modular meaning that you can upgrade the plug in boards such as the disc and tape boards and also completely bypass the tone filters. These new boards are available from Net Audio and make use of very high quality Burr Brown op amps, Elna Stargate and Wilma Polypropolene capacitors and surface mount resistors to ensure that the Quad 33 Pre Amplifier sounds as good as anything on the market today. More information on these upgrades can be found on Net Audio's website.

The Quad 33 Pre Amplifier is another popular piece of Quad hi-fi that features regularly in Ebay auctions with good condition amplifiers fetching somewhere in the region of £50-£100 which is a bit of a bargain if you intend to take advantage of Net Audio's Quad 33 upgrade path which will cost around £150-£200 depending on you chosen options. For under £300 you can get yourself a very high quality modernised pre amplifier.

This entry was posted on Friday December 29th, 2006 at 1:56 PM and is filed under Amplifiers. You can follow any responses to this entry through the RSS 2.0 feed. Comments are now closed.

23 Responses to Quad 33 Pre Amplifier

Quality hifi amplifier - accrington web Says:
December 11th, 2007 at 1:43 PM

[...] Quality HiFi Amplifier For sale is my Quad Electroacoustics Ltd 33/303 Pre/Power amp combo. Manufactured by Quad in Huntingdon in the Seventies this is a lovely quality pre and power amp combination. Noted for its natural sound this classic amplifier has been in my care for approaching 18 years. In that time I had it serviced by a trained Quad engineer. It sounds superb with my Electrostatics (also for sale see other thread) or with a set of decent modern speakers such as Kef, Tannoy or Mordaunt short. Rated at 45W this doesn't sound a lot compared to modern amps but as Quad only ever quoted the distortion free figure as opposed to peak that modern amps do you will find it has the guts to drive all but the most inefficient speakers to volume levels far higher than it should. Cosmetically its in good condition, audiably its lovely. Please note it takes its inputs from 5 pin DIN plugs but I will supply 2x 5 pin din to phono cables. Output to speakers is by 4mm banana sockets. £120 for both example pictures here, I'll post some of the actual amps tonight » Quad 33 Pre Amplifier » Quad 303 Power Amplifier __________________ Ian Technical God, No 1 Geek And Linux Guru Have you seen my Flickr pictures? [...]

Nihal bodhinayake Says:
April 12th, 2008 at 12:42 PM

My QUAD 33 pre-amp is 33 years old. Coupled with QUAD 405 amp and KEF 104aB speakers fed by AKG stylus and Lux cassette deck, we all enjoyed the music at its best for many years. Being in Sri Lanka, there are no QUAD agents or capable technitians to handle the problems. The guy who took to repair the circuit boards of the pre-amp left the island for a job abroad and cannot be traced. I need despertately the two detachable circuit boards of the pre amp. How do I set about this

Laki fernando Says:
April 21st, 2008 at 2:44 PM

Nihal, I would like to speak to you over the phone. Please let me have your contact number.

Laki Fernando

Lucky fernando Says:
May 12th, 2008 at 3:09 AM

Lucky, Thanks for the response, my phone is 0773 038 508
regards, Nihal

Hamad sheikh Says:
April 12th, 2009 at 3:07 AM

I can repair and restore QUAD equipment internal boards. Please check out my Ebay QUAD Upgrade services. Ebay item 200322151235. Regards, Hamad

Nigel grant Says:
August 20th, 2009 at 4:25 PM

My 33 preamp has a fault. It works properly only if I press in the filter "cancel" button. If the button is left out, there is a loud, unpleasant noise and no music or speech signal.

Please let me know if you have any idea what could be causing this, and whether it is repairable.


Hamad sheikh Says:
August 24th, 2009 at 9:13 PM

Nigel: What switch combination works? i.e. you must select a combionation be it 'cancel' or the other 5, 7, 10K settings. One setting must be selected. Regards, Hamad

Glen Says:
February 7th, 2010 at 6:45 AM

Hi Hamed
I have a quad 33 which needs service

where can i contct you


Hamad sheikh Says:
March 4th, 2010 at 10:17 PM

HI Glen, you can reach me via Ebay, look for seller amplifier_surgery. If you send me a message via Ebay, I can respond with email and phone details. Thanks, Hamad

Drichard.grant Says:
March 6th, 2010 at 9:58 PM

Have 33 with hum and 'crack' when i tried to reconn input leads.
Full service if poss please.
price ?

many thanks Richard 0116 2884227

Hans Says:
April 26th, 2010 at 11:27 PM

As posted on the 303 power amp page:

Hi everyone,

I just purchased a quad 303 / 33 in excellent cosmetic condition on ebay. I think that the amp/preamp were made or last serviced in 1985 according to a small sticker I found on the 303 transformer, the components looked okay but really dusty. I have also bought brand new speaker cables and plugs as well as replaced the old power cords that were provided. One important note is that I live in an old flat and the plugs are not grounded. Now here's my issue: everytime I turn on the 33/303 I can hear a loud crak on the right channel clearly visible on the LF driver and then a constant hiss. I have repeated the operation with the 4 pin din cable detached from the amp and preamp with the same result. This leads me to believe that it's a power issue. I've been looking on the web for a solution but nothing comes up. Could someone help me please. It was a rather costly investment and I'd hate to return it if it's something easy to fix. Thanks a lot.


Wade bunz Says:
August 9th, 2010 at 12:25 PM

Recently bought a new Plasma HDTV which only has optical audio outputs. All my older TVs had RCA audio output jacks which I could easily connect to the QUAD 33/303 preamplifier which drives my QUAD ESL-57 2 channel speakers. Do you know of a way to take the optical audio outputs of the Plasma HDTV and turn it into RCA outs ?
Wade Bunz

Onno meeuwis Says:
September 14th, 2010 at 3:54 PM

message forHans with the 303 that hisses. Pls contact me so I may send you a copy of Peter Walker''s letter with the fix. Onno

Therese Says:
December 4th, 2010 at 2:54 AM

Hi Guys
New to thissite. I have a quad 33 and 303 with quad electrostat speakers having a few tech problems with the system. Could anyone advise me if there is anyone in the Brisbane area who can service. Tks T

Leonard Says:
December 9th, 2010 at 11:27 PM

Interesting thread! Enjoying my Quad 33/303almost 30 years now. Need 'new' speakers. Am doubting between Kef Calinda, Tannoy Revolution R3, Kef Concerto Two (no reviews!), Vandersteen 2Ci or B&W DM12.
I like: neutral, wide soundstage, musically, deep definated low end, for: classic (piano!), ECM-cd's, singer songwiters.
Any experience and advice would be very welcome!
Thanks & regards, Leonard

Samar Says:
January 25th, 2011 at 2:54 PM

I have Quad33/303. Balance pot of Quad 33 is not functioning properly. If I want to buypass the balnce control pl suggest the procedure. Or inform the replcement value and the availability of balance pot as well as volume pot.

Karl Says:
February 1st, 2011 at 9:43 AM

I have a similar problem as Samar. Is there a way to bypass balance, or can i get a new balance-thingie somewhere?


Hamad Says:
March 2nd, 2011 at 6:14 PM

HI Samar, Karl, if you are in the USA or Canada, you can email me on amplifier_surgery _AT_ yahoo com for a restoration if interested.

Roger Says:
August 27th, 2011 at 11:19 AM

I have quod 33/405 from new uk sale 1980, I have a chanel card from my 33 down, can I get it repaird or do I replace 1 or bouth cards

Kl Says:
October 4th, 2013 at 11:22 AM

I have been given a Quad 33 preamp. I do not have a Quad power amo. Can anyone tell me whether I can use the preamp with say a Naim poweramp which I can get my hands on?


Masato Says:
November 12th, 2015 at 9:59 PM

One last question how big of a power amp and sprekeas are you looking for? Do you happen to know the specs on the last setup? I may have an old Alesis power amp in storage still. I believe it was 200 or 400 watts.

John p Says:
November 22nd, 2015 at 6:50 PM

I have a Quad 303/33 coupled with Epos ES11. Amazing.

Stuart Says:
November 28th, 2015 at 10:18 PM

One set of speakers that match really well are celestion ditton 15, not surprising due to the similar age.

Not the ultimate hifi, especially with modern digital sources, but use a good turntable and you realise what we have lost in the rush for convience.

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