I'm a tweeker by nature and if something can be modded I'm in. A good pwr supply is the heart to any component as you know. If I win this bid I'll probably start with the upgraded pwr supply you mentioned. I still have a soldering iron among my bag of tricks so adding some of these features will be interesting and fun. Keep in touch Darkmoebius.
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Well, you can easily do the power supply upgrades by either buying a totally new $26 snubberized PS kit (picture)from Brian at ChipAmp.com or you can buy his $29 PS upgrade kit. The new PS kit is really simple. But there were also changes made to signal/amp board(#2). Here's a list of all the mods from Rev B. to Rev 3: LM3875 Revision 3 PCB set changes: 1. rectifier board: modified to allow for optional Carlos Filipe (carlosfm) snubberized power supply setup:((100nF+1 ohm) || 100nF) a. placement created to allow for 10,000uF caps to be mounted under PCB(power supply pcb can be mounted to chassis with 1.5" standoffs if caps are used) b. added placement for LED with series resistor (can be wired off board) c. size increased from 1.2" tall to 1.5" tall 2. amplifier board: changed R3 footprint to compact metal film resistor (will still allow for larger resistors, mounted vertically) a. simplified ground plane, maximizing area by removing signal ground plane b. optimized connection between the main ground and the signal ground c. added placement for 0.1uF caps on rails in case the snubberized setup is used (100uF caps would be mounted in the other holes) d. surface area for power planes has been increased e. moved zobel network to allow for more contiguous ground plane 3. overall board size increased to 2.9" wide x 5.4" tall before separating components Most of the signal mods have to do with cleaning up the ground plane and giving more room for large alternate components. Since you probably won't be doing a lot parts experimenting, not a big deal. They probably do not make a huge sonic difference, though the 2c option may make life a little easier for that part of the snubberize PS implementation. For the dual-mono PS option, you will need to get another of the power transformers that the seller used. Try to use the same manufacturer and model, if possible. Anyway, you can add extra features to that amp fairly easily and it will be great. |
Wow, You are the man. Not knowing enough about this piece puts me in the dark somewhat(no pun intended). I wonder if the upgrades you mentioned can be allocated into this amp. It seems with the upgrades the one input and the dual-mono one can have with these kits $100 is about all I will go. Many thanks to you Dark and Gmood for the posts. Stay tuned, Bret |
Hi South43, I looked at the auction and have confidence that it was built from one of best and widely used Gainclone kits, Brian Bell's. I owned one of them and they are extremely well thought out and laid out. Judging from the photos, the builder paid good attention to wiring layout and assembly. It looks to be a pretty damn go build. Just one thing to keep in mind, this is a Rev. B amp. The newer Rev 3 amps benefitted greatly from their ability to run Carlos FM's Snubberized power supply. It made a sizable performance upgrade. Also, Gainclone's benefit greatly from true dual mono power supplies(as do all amplifiers). All in all, I think it cost ~$200-225 to build the whole dual-mono Rev. B sheebang - chasis, knobs, stereo volume pot, input selector, transformers, power cord w/ good plugs, rca plugs, etc. Check to see what kind of volume pot he used - Alps blue or whatever? Also, consider that single input limits it's flexibility. I guess what I am saying is that you probably shouldn't go higher than $100-150 in this auction. You can buy a dual-mono kit from Brian with Carlos' snubberized power supply for ~$90 w/tax+shipping. All the other parts will cost ~$125. Assembly is extremely easy, any beginner can do it. ANd there is pletny of online help on DiyAudio.com or the other Gainclone forums. |
Darkmoebuis I thank you for the added comments and info. I took the plunge and put a bid on the amp which is a intergrated piece(50 watts). Don't have to worry about a pre. This unit only has one set of inputs and I do have a NAD tuner as well as my Philips sacd player as a source. I also plan on reaquiring a pair of Infinity primus 150 spkrs. They are 8ohm rated very detailed and are I believe 89db. I'll keep you informed if I win and how everything works out. Good listening! Bret |
South43 you must be very careful of the match between the speakers and the Gainclone. The closer the speaker load is to 8 ohms and of decent sensitivity..say 90 dB or higher. The better the results when using one. Gainclones are not designed to run tough or wild impedance loads. With your taste in music and the right speaker match you'll have a great time with the GC. It stopped my amplifier hunt dead in its tracks for the first time in years. I don't even look at equipment for sell any more and haven't for nearly 4 or 5 months...that should tell you something. I swapped amplifiers atleast 11 times in the last three years. A tubed preamp is a good match for these units. As long as it's not a noisy tubed preamp... the GC is very sensitive to upstream noise. Great post Darkmoebius! Have fun! |
I thank you for your reply and info. I did do a little research with the links supplied from the seller. I even registered with diy audio to see what's going on in that camp. The pics provided show a really nice build and with few parts as you mentioned. Sonics are the order of the day for me however and without a source to audition its a little tough to make a decision. The seller has decribed the sound of this piece and with my musical tastes(acoustic jazz,gospel,vocals)it seems that this might be something I could live with. Stay tuned. |
There were an army of Do-It-Yourselfer's(DIY'ers) who committed themselves to figuring out the design behind 47 Labs famed amp a few years ago. Checkout Since there were only 9-15 parts in the whole sheebang, it didn't take long. A decent working model really shouldn't cost more that GainClone.com, it is solely dedicated to DIY Gainclone designs. Also DiyAudio.com's ChipAmp forum. Since there were only 9-15 parts in the whole sheebang, it doesn't cost a lot ot make one, although it did take a lot of experimentation over a a couple of years to get the best out of it. The evolution of the GainClone was an impressive group effort to watch. Some pretty talented people were actively involved along with a slew of beginners. Literally hundreds of permutations were tried. Which really stands as a testament to the effort 47 Labs put in because it was all done by a single person. (though, his prices - sheesh!) Anyway, some of the DIY crowd went on to make actual commercial products. ChipAmp.com sells complete Gainclone kits of tried and true high-performance designs. Everything you need for ~$80.00, excluding chasis and knobs. Also, Peter Daniel, one of the mainstays and leaders of the DIY movement went on to offer the Audiosector Patek line of amps as reviewed favorably by 6Moons.com webzine. They also sell kits. |