Quad 303 driver boards

A good mod, and one quad did on later production, was to mount the large power supply and output caps up the other way. I have original 405 boards which ive serviced with the dada kit and replaced the op amps to opa604. To do this i ordered two new amplifier m12038 driver boards directly from quad. Anyone who knows these amps will be aware that the previous transistors had an oversized flange which quad utilised to place a large metal heatsink over the transistor, however, the replacements bc441 and bc461 do not have this. Living with the quad 33 preamplifier and the quad 303 power amplifier. I read that quad took a long time bringing out the 33303 because it had to compete, sound wise, with all those lovely tube amps that were around at the time. 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. Quad 303 power amplifier selling as used here we have a couple of vintage quad items. The list of motherboards, compatible with the intel core 2 quad q6700 microprocessor, is based on cpu upgrade information from our database. Monoblocking quad 303 audioholics home theater forums. Hi group, i am going to share a repair that i performed on a quad 303 power amplifier. Quad 303 amplifier modified for general purpose lab amp.

It would be useless to mount the old parts on new pcbs so all components are interchanged. Looks neatly done with only evidence of one partially lifted pcb track, which i can likely glue down anyway. This is how to properly slot boards in a quad 33 preamp description the quad 33 selects and controls the radio tuners, gramophone pickup and tape recorder connected to it and feeds the. Quad 33 ultimate and full component replacement options. Quad 303s often suffered with ground loop hum and will probably cure the problem with a 2 core mains cable with no earth. Other parts include a very highquality potted transformer, two 10,000uf filter capacitors, some power supply wiring, a large frontmounted heatsink, an led and some sockets. Bailey quadricep physical therapy strengthening boards. He has put his mcintosh aside and uses the 2 channels of one. These quad boards can be adjusted to different angles depending on the purpose or intensity of the exercise. Also bear in mind that the quad 405 and 4052 was a constantly evolving design. If your not so confident it might be cheaper and easier to just buy new boards from quad.

View and download quad 33303 instruction booklet online. Baileys quadriceps boards are designed for use during physical therapy and rehabilitation exercises to help to strengthen leg muscles. Fixing quad 303 boards in the chassis we often get the question if we can supply the plastic clips for mounting the quad 303 driverboards and powersupply boards in the chassis, as they can break off while removing one of the boards. While the nad sounds wonderfully for a builtin amp, when i add the quad to the system, the improvement is spectacular. They used to have these bloody little plugin circuit boards that were frightfully dinky and frightfully clever. The quad 303 power amp is perhaps the more well known of the two components. To do this i ordered two new amplifier m12038 driverboards directly from quad. For the highest reliability and performance we can replace the entire set of resistors, capacitors and semiconductors on the seven circuit boards. The vocals with the quads have a much more realistic consistency, all mids are more clearly audible, the lows. Rebuilding the quad 303 recently i decided to rebuild my quad 303. Otherwise, play about rebuilding with inexpensive clone boards which are. Dealer has good feedback, item arrived very well packed. Many would argue that the 303 was actually a better amplifier. Really enjoyed your you tube video on the quad 303.

Both these boards can be accessed without opening the case. Quad 303 power amplifier power supply repair page 1. Once, i got the idea to use quad ii instead of 303 s which i am now using. My quad 303 when power up, 1 of the speakers right channel has a hissing sound then a pop sound when power cuts in. Quad 303 power amplifier fitted with cannon connectors. Hi all, i am purchasing another quad 303 so that i have one for each speaker and i will need to monoblock them to do this. The powertrain control module pcm operates its output devices, such as solenoid valves, relays and indicator lights, by commanding a driver module. View and download quad 303 service supplement manual online. A few evenings ago i promoted my quad 303 from the study system to the big rig, inspired by finally buying the 4pin din to rca cable that would make the move a possibility and what ive read about it being highly suitable for powering my esls 57s, the same vintage as the 303. By far the easiest way of rejuvenating a tired 40 year old quad 303 amplifier.

Bias current settings in quad 303 and 50e quad produced two vintage transistor power amplifiers with a bias current, the 50e and d variant, and the 303. Quad 33 preamplifier, fm3 tuner, 4051 to the right on the record cabinet and 303 on floor power amplifiers. Quad 303 highend boards and capacitor set dada electronics. All the highend boards for quad 303 and 405 are available again as well as the highend revisio new blog articles 06sep2017. As shown the amplifier tested to spec and the boards were unsoldered and. If your house has an rcd then you will be safe from an electric shock if there is an internal short. Theres a dynamic driver that handles bass and midrange sound. There was a seller on ebay that was sellling replacement amp driver boards. Like all quads hifi it is beautifully designed and engineered and indeed won a council of industrial design award in 1969. In those cases both driver print boards became too warm and it is necessary to replace them.

The 1more quad driver represents a new level of price to performance for in ear headphones. However, as i am a newbie, i have absolutely no idea how to monoblock a power amp, what i will need etc. This is a major overhaul using modern components, 1% tolerance low noise metal film resistors, polyesterpolypropylene film capacitors, low. Launched by quad in the late sixties this amp quickly gained a viable reputation as a great amplifier. We all know that adding more to an audio product doesnt necessarily make it better. Quad303 driver board diodes mr103,4,5,6 dada electronics. The quad 33 pre amplifier is a classic example of british hifi at its very best. Would it be possible to say, generally speaking, whether the sound in any way be different. Looking for replacement driver boards for the quad 303 amplifier. With this in mind, two boards make up almost the entire amplifier. The driver boards have had new resistors fitted 1% or better, the caps have been replaced with ansar, black gates and also a large.

A few electrolytic caps have been replaced on the driver boards, and some trim pots. I am listening to old analogue long playing recordings with classical music dating from 1949 to 1979. Quad 303 manual stereo power amplifier hifi engine. Advice please, i have just reconditioned a quad 303 and within that replaced transistors 384956 on the driver boards and 38495 on power supply board. A quad driver module operates 4 electronic switches for 4 output devices. Instead of breaking the transformer links in a 50e, we measure the voltage across r30 and r31. Quad amplifier 303 for sale in uk view 14 bargains.

All the highend boards for quad 303 and 405 are available again as well as the highend revisio. The 303 was introduced in 1967 and was sold until 1985. Although for each board we provide pcb and bios revisions that support the processor, this page is updated less frequently than individual motherboard support pages, therefore we encourage you to visit those page as they may contain more uptodate data. Save quad 303 to get email alerts and updates on your ebay feed. As a repairer, i can tell you that the quad 405 and 4052 are perhaps the easiest amplifiers to service. After a lot of talking about it, its time i turned my attention to modifying replacing my quad 405 boards. The quad 303 was not quads first transistor amplifier the quad 50 was a push pull transistor design with a multi tapped output transformer aimed at professional users due to its high cost and odd connections an interesting point about the quad50 and the quad303 is that they were intentionally made the same size as the quad ii valve.

Vu meter driver board level meter driver module with header backlight power. Quad 303 driverregulator board installation this instruction covers installation of both driver and regulator boards. I have carefully checked all components and have replaced any failed or suspect but i still cant get enough voltage across pins 4 and 6 when adjusting rv101. A quad 303 a2 audio power amplifier is modified to a general purpose quad. In fact a simple and cheap alternative solution is using 4 mm plastic cableties, like in the pictures. Replacement driver boards for the quad 303 diyaudio. And that housing was identical to that of the 50e mono power amplifier, an exceptional product that came in production just before 303. Hi, as posted previously, ive been having trouble setting quiescent current on one of the 2 driver boards. Some quad 303 power amps are heavily used through the decades. Quad 303 amplifier modification to general purpose lab amp from 303 a2.

Used, quad 303 circuit boards from a working ampl this was my dads and i now have no use for it. A view of new net audio plugin boards inside a quad 33 preamp. In those cases both driver print boards became too warm and. On the driver boards you can use 1n4148 with good results, we use them in our highend boards.

A driver module is an electronic switch that turns on to complete the ground circuit and operate the 12 volt device. Quad 303 rebuild and upgrade start to finish youtube. So a good value in practice is 10mv across r124 and r125 pin 4 and 6 on the driver boards. Quad 33 preamplifier, quad 303 power amplifier hembrow. The 303 was easy because the quad ii was this shape and we had a cabinet that it fitted in. The quad 303 is a two channel power amplifier primarily designed for high quality domestic installations. Also excellent clone boards exist on ebay for 303s so you could consider building new boards to replace the old ones. If you have only purchased the regulator board then after installation only steps 6 to 8 need apply although you can check your original board setup for correct bias and voltages.

Hi, i have a lovely little vintage system that sounds great to me and includes a pioneer pl112d turntable with shure m75ed cart, quad 33303 amp and mordaunt short pageant speakers. Bios aa revs slacu e30148204 slacu e30148205 slacu e30148206 slacu e30148207 slacu e30148208 slacu e30148301 slacu e30148302 slacu e30148303. It is ideally suitable for driving loudspeakers in the 416 ohm range and will provide an output of up to 45 watts per channel depending upon the load impedance. The 303 is considered by many to be the best solid state amplifier that quad built particularily if you are driving quad esl 57s. In 2008 i took a quad 303 amplifier and 33 preamp as part exchange against. Iag service department, unit 4, st margarets way, stukeley meadows industrial estate, huntingdon, cambridgeshire, pe29 6eb. Im not sure of the exact vintage of the quad amp as i believe they. The list of motherboards, compatible with the intel core 2 quad q9650 microprocessor, is based on cpu upgrade information from our database. Originally i planned on upgrading the existing boards myself but i dont have the time, knowledge or confidence to execute this to the level id like to achieve, so im looking at just. Newly constructed replacement ars quad 303 boards undergoing setting up and testing. My life with quad a personal recollection by barry hunt. Couldnt resist ordering what looked like a mint condition 303 from the bay. Quads service documentation lists five different variations of the 405 circuit and a further 4 different versions of the 4052 circuit. Ultimate amps for the ultimate loudspeaker net audios quad 33 and 303.