Quad 303 driver boards

Vu meter driver board level meter driver module with header backlight power. My quad 303 when power up, 1 of the speakers right channel has a hissing sound then a pop sound when power cuts in. Hi, as posted previously, ive been having trouble setting quiescent current on one of the 2 driver boards. View and download quad 303 service supplement manual online. 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. To do this i ordered two new amplifier m12038 driverboards directly from quad. Would it be possible to say, generally speaking, whether the sound in any way be different. Monoblocking quad 303 audioholics home theater forums. Bailey quadricep physical therapy strengthening boards. Couldnt resist ordering what looked like a mint condition 303 from the bay. Quad amplifier 303 for sale in uk view 14 bargains. I have original 405 boards which ive serviced with the dada kit and replaced the op amps to opa604. Quad 303 power amplifier fitted with cannon connectors. If your not so confident it might be cheaper and easier to just buy new boards from quad.

And that housing was identical to that of the 50e mono power amplifier, an exceptional product that came in production just before 303. 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. Instead of breaking the transformer links in a 50e, we measure the voltage across r30 and r31. He has put his mcintosh aside and uses the 2 channels of one. Some quad 303 power amps are heavily used through the decades. View and download quad 33303 instruction booklet online. For the highest reliability and performance we can replace the entire set of resistors, capacitors and semiconductors on the seven circuit boards. 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. It would be useless to mount the old parts on new pcbs so all components are interchanged. Many would argue that the 303 was actually a better amplifier.

Used, quad 303 circuit boards from a working ampl this was my dads and i now have no use for it. Quad 33 ultimate and full component replacement options. There was a seller on ebay that was sellling replacement amp driver boards. The quad 303 power amp is perhaps the more well known of the two components. Quad 33 preamplifier, quad 303 power amplifier hembrow. The powertrain control module pcm operates its output devices, such as solenoid valves, relays and indicator lights, by commanding a driver module. 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.

Quad 303s often suffered with ground loop hum and will probably cure the problem with a 2 core mains cable with no earth. Launched by quad in the late sixties this amp quickly gained a viable reputation as a great amplifier. Quad 303 power amplifier selling as used here we have a couple of vintage quad items. 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. Not only does it have the unique triples circuit, but it also has a reputation for robustness and is known for sound quality even now. Both these boards can be accessed without opening the case. 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. Quad 303 highend boards and capacitor set dada electronics. Theres a dynamic driver that handles bass and midrange sound. In 2008 i took a quad 303 amplifier and 33 preamp as part exchange against. All the highend boards for quad 303 and 405 are available again as well as the highend revisio.

They used to have these bloody little plugin circuit boards that were frightfully dinky and frightfully clever. While the nad sounds wonderfully for a builtin amp, when i add the quad to the system, the improvement is spectacular. If your house has an rcd then you will be safe from an electric shock if there is an internal short. After a lot of talking about it, its time i turned my attention to modifying replacing my quad 405 boards. Looking for replacement driver boards for the quad 303 amplifier.

Also excellent clone boards exist on ebay for 303s so you could consider building new boards to replace the old ones. Save quad 303 to get email alerts and updates on your ebay feed. Quad303 driver board diodes mr103,4,5,6 dada electronics. Really enjoyed your you tube video on the quad 303. Quads service documentation lists five different variations of the 405 circuit and a further 4 different versions of the 4052 circuit. 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. Replacement driver boards for the quad 303 diyaudio. With this in mind, two boards make up almost the entire 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. A view of new net audio plugin boards inside a quad 33 preamp. A few electrolytic caps have been replaced on the driver boards, and some trim pots.

Looks neatly done with only evidence of one partially lifted pcb track, which i can likely glue down anyway. All the highend boards for quad 303 and 405 are available again as well as the highend revisio new blog articles 06sep2017. The quad 303 is a two channel power amplifier primarily designed for high quality domestic installations. Iag service department, unit 4, st margarets way, stukeley meadows industrial estate, huntingdon, cambridgeshire, pe29 6eb. These chinese pcbs seem better made than the quad original pcbs but i had already rebuilt the amps using the original pcbs so my. A good mod, and one quad did on later production, was to mount the large power supply and output caps up the other way.

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. On the driver boards you can use 1n4148 with good results, we use them in our highend boards. 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. Rebuilding the quad 303 recently i decided to rebuild my quad 303. Bios aa revs slacu e30148204 slacu e30148205 slacu e30148206 slacu e30148207 slacu e30148208 slacu e30148301 slacu e30148302 slacu e30148303. 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 manual stereo power amplifier hifi engine. 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. The 1more quad driver represents a new level of price to performance for in ear headphones. Based on the original quadschematics, latest version. Living with the quad 33 preamplifier and the quad 303 power amplifier. Ultimate amps for the ultimate loudspeaker net audios quad 33 and 303. Quad 33 preamplifier, fm3 tuner, 4051 to the right on the record cabinet and 303 on floor power amplifiers.

As shown the amplifier tested to spec and the boards were unsoldered and. 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. To do this i ordered two new amplifier m12038 driver boards directly from quad. 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. Like all quads hifi it is beautifully designed and engineered and indeed won a council of industrial design award in 1969.

Baileys quadriceps boards are designed for use during physical therapy and rehabilitation exercises to help to strengthen leg muscles. The list of motherboards, compatible with the intel core 2 quad q6700 microprocessor, is based on cpu upgrade information from our database. Once, i got the idea to use quad ii instead of 303 s which i am now using. By far the easiest way of rejuvenating a tired 40 year old quad 303 amplifier. Quad 303 rebuild and upgrade start to finish youtube. Im not sure of the exact vintage of the quad amp as i believe they. In those cases both driver print boards became too warm and it is necessary to replace them. However, in the case of the 1more quad driver inear headphones, more is most definitely much, much better. A driver module is an electronic switch that turns on to complete the ground circuit and operate the 12 volt device. The 303 was easy because the quad ii was this shape and we had a cabinet that it fitted in. Dealer has good feedback, item arrived very well packed. A quad driver module operates 4 electronic switches for 4 output devices. However, as i am a newbie, i have absolutely no idea how to monoblock a power amp, what i will need etc. Hi group, i am going to share a repair that i performed on a quad 303 power amplifier.

We all know that adding more to an audio product doesnt necessarily make it better. A quad 303 a2 audio power amplifier is modified to a general purpose quad. This is a major overhaul using modern components, 1% tolerance low noise metal film resistors, polyesterpolypropylene film capacitors, low. 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. 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.

Quad 303 amplifier modified for general purpose lab amp. These quad boards can be adjusted to different angles depending on the purpose or intensity of the exercise. In those cases both driver print boards became too warm and. Quad 303 amplifier modification to general purpose lab amp from 303 a2. Quad 303 driverregulator board installation this instruction covers installation of both driver and regulator boards. The list of motherboards, compatible with the intel core 2 quad q9650 microprocessor, is based on cpu upgrade information from our database. So a good value in practice is 10mv across r124 and r125 pin 4 and 6 on the driver boards. My life with quad a personal recollection by barry hunt. The quad 33 pre amplifier is a classic example of british hifi at its very best. The 303 was introduced in 1967 and was sold until 1985. Quad 303 power amplifier power supply repair page 1.