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WITHDRAWN OR RELISTED: On Hold: Quad 33/303 pre-power plus matching FM Tuner


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Item: Quad 33/303 pre-power and FM tuner
Location: Sydney
Price: $690
Item Condition: Very Good - upgraded by Dada Electronics some years back (2010) - full details below - but see my latest comment.
Reason for selling: cash flow
Payment Method: bank deposit, cash, paypal
Extra Info: Extra pics now added - the units are in good condition but do have marks, imperfections in finish. However, they are upgraded, so if you can find immaculate examples which are also upgraded then go for them, at whatever price. Most prospective buyers will at least know these by reputation. The sound is warm, smooth, but not mega powerful at about 45w/channel. But that's about all most people will get out of valve amps in pentode mode, which these were developed to replace. The shape of the power amp is similar to the shape of the Quad valve monoblocks, possibly so they could use the same sort of packaging! They do work well with most speakers and are so appealing physically as well that I had to have them even though they were under-utilised at my place. 

Notes on Upgrades:

Quad Upgrade by Dada Australia - Esmond Pitt - dada.australia@bigpond.com

The 303 Power amp service consists of: 1. Replace output coupling and PSU caps with 3 x 4700uF BHC Aerovox, 25,000 hour lifetime. 2. Replace all other electrolytics. Increase the input stage supply decoupling capacitors to 470uF to lower hum. 3. Replace all trimpots with 12-turn so they can be adjusted much more accurately, 16x when you take into account that the originals only have 270 degrees travel.

4. Replace all resistors and diodes on the PSU board. 5. General cleanup. Change the input and Zobel capacitors if necessary. Replace the lamp if necessary. Supply missing feet if necessary. 6. Readjust the rail voltage, centre voltages and bias currents. 7. Test and measure. 8. Listening test.

 

The 33 pre-amp service consists of: 1. Replace all electrolytics in all boards: this comes to about 30 of the little fellas. Increase a few, e.g. the phono supply decoupler and the amplifier board bootstrap, in line with modern practice. 2. Replace *everything* on the PSU board except the transformer. 3. Change the phono input impedance from 68k to 47k. 4. Implement the S1 side of the phono adapter board as a CD input, 400mV nominal level.

5. Replace the biassing resistors and the output capacitors on the tape adapter board. Raise the output capacitor from 680nF to 2.2uF to remove a slight bass roll-off. 6. Replace the lamp if necessary. Supply missing feet if necessary. 7. Test, measure, listen.

After all this, both units typically measure better than original factory specification, mostly due to modern components being better, also to use of metal film instead of carbon resistors.

FREIGHT: ask me about this, but I have a Sydney buyer who may take them today.
 
Pictures: More just added as at 9.10am Sunday. 

 

 

 

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Edited by Spinnergeoff
added info.
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Love the style, look to be in beautiful condition for their age, and all revitalised classic quality.

Hook up some Celestion SL-6's and let it swing. At the price you can't go wrong.

Edited by PicoWattson
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Setiawan has decided against, as there's a "boomp" on startup and a balance slider that's not doing the right (right/left?) thing. Never used it myself! I may withdraw from sale and get those things sorted. Not sure about the noise on startup - used to be relatively common before they added time-delay relays to amps as a matter of routine.

Any Comments?

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