I have also asked whether any component packs that are available on Taobao are available through this supplier (e.g. see http://item.taobao.com/item.htm?id=...416_2297358_8935934:1354897536_3k2_1484077414)
Okay 1st build done - a few issues
1. Mains round here is nearer 244 so 40v secondary nearer 43V and after the bridge and offset rail, one is pretty close to 63V == same rating as the smoothing caps... So I put 6 diodes in series to the bridge just to bring it back a bit
2. Amp is a bit noisy - can hear faint hissing in tweeter even with input shorted - so am going to replace a few of the carbon resistors with metal film, and maybe also reduce the overall gain back down to .75V instead of 0.5V
My scope is playing up so can't resolve where it is originating from at the moment
3. Toroidal transformer hum is so loud I can hear it when I enter the room :-(
Maybe there is a small offset on the mains (a DC component), so will use a bridge and couple of caps to try to solve.
4. I stuffed up the PCB layout re-orienting one half of the output stage, so a few wire links placed trackside to resolve!
Apart from that it sounds great and I think I may have overdone the heatsinks - it barely gets warm (it also weighs 11.5Kg!).
Here are some pics -
Output protection is just a fuse... will build a solid state switch for this.
Not the neatest layout, will try harder next time
View from above
Assembled - it's only going to sit behind a subwoofer bin so won't in fact be seen, but hopefully heard!
Ordered some more output transistors for the next build
Cheers
Ed
What is the pcb end?
please. could you upload it.
It unexelente work. thanks for sharing.
Best regards sergio.
A quick check with a multimeter shows it to be a true ground plane. The board feels substantial, and seems to have fully through hole plating.
Apart from edharman i don't know of anyone else. I've had quite a few pm's over the last year asking for the diagrams etc but not heard if anyone actually constructed it or not.
I still want to build it but i am still lacking the funds to dive in and give it a go. I think i'll have to buy the components in batches.
I still want to build it but i am still lacking the funds to dive in and give it a go. I think i'll have to buy the components in batches.
405man, I have modified my build as per the comments regarding my stretching the output transistors, so now have effectively cut out the center of the pcb and mounted it across the U-channel heatsink, with both sets of output transistors on the legs of the U-section - will post a picture when I get a moment.
Sound-wise it 'sounds' better than my RX771 Yamaha receiver, albeit I am actually only using it to power a sub, so hardly a realistic stress test. I definitely will replace the input resistors with low noise ones - when I originally tested it using a conventional speaker there was an audible hiss from the tweeter if you stuck your ear right up to it - hardly a realistic test but indicative of some noise, but not an issue for a sub amp.
Sorry I don't have test equipment sensitive enough to perform actual performance measurements.
I am currently awaiting delivery of 2kg of potting compound to 'kill' the hum from the toroidal trafo, but other projects have meant I have had little time to tinker, or build further clones (which I will definitely do), tbh I put it together, it worked and I got on with building my sub (modified DecWare wicked one with 2 x SEAS L26RO4Y drives) and have been using it daily since
Ed
Sound-wise it 'sounds' better than my RX771 Yamaha receiver, albeit I am actually only using it to power a sub, so hardly a realistic stress test. I definitely will replace the input resistors with low noise ones - when I originally tested it using a conventional speaker there was an audible hiss from the tweeter if you stuck your ear right up to it - hardly a realistic test but indicative of some noise, but not an issue for a sub amp.
Sorry I don't have test equipment sensitive enough to perform actual performance measurements.
I am currently awaiting delivery of 2kg of potting compound to 'kill' the hum from the toroidal trafo, but other projects have meant I have had little time to tinker, or build further clones (which I will definitely do), tbh I put it together, it worked and I got on with building my sub (modified DecWare wicked one with 2 x SEAS L26RO4Y drives) and have been using it daily since
Ed
Here are a couple of shots of the amp after modifying the layout somewhat after criticism from Sakis
So for the next build I will re-do the pcb artwork to neaten it up a little.
I've measured around ~30v peak-peak across the subs, and that was at an outrageous volume - floor shaking etc (concrete suspended floor, parquet and carpet on top), and even playing at 'loud' volumes for extended periods the heatsinks barely get warm, so I think the enclosure/heatsink could be shrunk considerably
Ed
So for the next build I will re-do the pcb artwork to neaten it up a little.
I've measured around ~30v peak-peak across the subs, and that was at an outrageous volume - floor shaking etc (concrete suspended floor, parquet and carpet on top), and even playing at 'loud' volumes for extended periods the heatsinks barely get warm, so I think the enclosure/heatsink could be shrunk considerably
Ed
Though directly related to the 405-2 this link provides some insight into the operation of the bridge in the currentdumping output stage
Quad 405-2 upgrades
I have a pair of Quad built 606s which I am converting to mono blocks which can be switched to either stereo or paralled mono, I may post some photos when I get them finished
Stuart
Quad 405-2 upgrades
I have a pair of Quad built 606s which I am converting to mono blocks which can be switched to either stereo or paralled mono, I may post some photos when I get them finished
Stuart
Here are a couple of shots of the amp after modifying the layout somewhat after criticism from Sakis
So for the next build I will re-do the pcb artwork to neaten it up a little.
I've measured around ~30v peak-peak across the subs, and that was at an outrageous volume - floor shaking etc (concrete suspended floor, parquet and carpet on top), and even playing at 'loud' volumes for extended periods the heatsinks barely get warm, so I think the enclosure/heatsink could be shrunk considerably
Ed
Where is the mask pcb and components?
BOM and Layout
Here are links to the BOM, drill mask and track.
All were copied from the widely available service manuals, so I take no credit or originality for it/them!
BOM
drill mask
track
Ed
Here are links to the BOM, drill mask and track.
All were copied from the widely available service manuals, so I take no credit or originality for it/them!
BOM
drill mask
track
Ed
hi.
i have made this amp and it works, but i have not finished it yet. i have used the pcb from post 15, there is some small errors in the original bom contra original schematic, there is a couple of resistors in the schematic there is missing/wrong value in the bom, the original schematic is correct, i have also used lm334 +120ohm resister instead of cr1(j503) i could not find this anywhere. i have a couple of homemade els i like to drive with this amp.
i cant say much about the sound right now but then i tested the amp (one channel) on a cheap speaker the sound was very very good
regards
Ls
i have made this amp and it works, but i have not finished it yet. i have used the pcb from post 15, there is some small errors in the original bom contra original schematic, there is a couple of resistors in the schematic there is missing/wrong value in the bom, the original schematic is correct, i have also used lm334 +120ohm resister instead of cr1(j503) i could not find this anywhere. i have a couple of homemade els i like to drive with this amp.
i cant say much about the sound right now but then i tested the amp (one channel) on a cheap speaker the sound was very very good
regards
Ls
I'm just reviving an old thread here.
Has anyone cloned the QUAD 909, is it actually worth while ?
My DIY spirit is fighting with economic sense, You can buy 909's for about £400, the transformer and caps alone come close to that. OK I don't like the 909 styling and I have my own heatsinked case but it just doesn't make sense to build DIY.
Has anyone cloned the QUAD 909, is it actually worth while ?
My DIY spirit is fighting with economic sense, You can buy 909's for about £400, the transformer and caps alone come close to that. OK I don't like the 909 styling and I have my own heatsinked case but it just doesn't make sense to build DIY.
Hi - I am just about to start the build of 2 x 4 channel amps based on the 909, and agree that the economics are a little tough- I think I paid around £1200 for components (bought just before Xmas so can't remember precisely however that does not include soft start and protection circuitry. I literally just picked up this morning the chassis/heatsinks from the anodisers so my build will only now start in earnest.
As to style - agree the originals are not to everyone's taste and mine are markedly different however they are designed to be heard and not seen, and in any case are going to sit behind some equally quirky speakers, the Linkwitz LX521's - so as to which is the beauty and which the beast is much down to personal taste. Ultimately for me function over form is my priority
Here's a link to the amp thus far Amp
As to style - agree the originals are not to everyone's taste and mine are markedly different however they are designed to be heard and not seen, and in any case are going to sit behind some equally quirky speakers, the Linkwitz LX521's - so as to which is the beauty and which the beast is much down to personal taste. Ultimately for me function over form is my priority
Here's a link to the amp thus far Amp
I'm using standard Epcos ones sourced from Farnell, I can't find the article I remember reading that applied specifically to the 606 but this article for the 405 shows that the distortion introduced due to an imbalanced bridge is pretty negligible http://www.keith-snook.info/wireless-world-magazine/Wireless-World-1978/Current%20dumping%20-%20does%20it%20really%20work%20DCD.pdf