Firefox 0 Report post Posted August 9, 2004 Finally completed my amp after a long time... And so.. I present to you guys: the BBamp Rev. 3. =) Share this post Link to post Share on other sites
Firefox 0 Report post Posted August 9, 2004 The power supply: Toroid brand toroidal transformer. I intend to replace with either a Talema or Avel Lindbergh encapsulated trans. soon. Hybrid power supply with RC filtering for noise removal and filtered zener for regulation. Filter caps are low impedance Panasonic FC's. The zener filter caps are very low impedance Panasonic HFZ and the output caps are Panasonic FC with Sanyo Oscon's! Share this post Link to post Share on other sites
Firefox 0 Report post Posted August 9, 2004 (edited) Heart of the amp. This design is is very similar to the BBamp Rev. 2 which av98m now owns. However, I'm using handmatched, NOS, pure copper Holco resistors and coupling the opamps directly with Sanyo Oscon's. Amongst the best of each of the 2 types of components! Close up of the workz: Edited September 5, 2004 by Firefox Share this post Link to post Share on other sites
Firefox 0 Report post Posted August 9, 2004 (edited) Some information about the amp. As with the BBamp Rev. 2, this Revision also used PTFE insulated, ultra pure, 5N (99.999%) silver wire in the signal path. For power connection between the switch and amp, I used PTFE insulated, ultra pure, 6N (99.9999%) copper wire. The same stuff used in the top-of-the-line XLO cables! In the 2nd revision, I opted for low mass gold-plated RCA's. Less metal in the signal path is always better. Especially if the metal is brass! In this revision, I opted for very much more costly Vampire CM2F/ OFC RCA jacks. These are not low mass but they're made of oxygen-free-copper and gold plated! The volume pot is still the same high quality Noble pot used in high-end equipment from Cary Audio Design and Ray Samuels. I feel it's the best continuous rotation pot available now. The resistors used are NOS, non-magnetic Holco H8 resistors. These have copper leads and end-caps which are non-magnetic unlike ordinary metal film resistors with Nickel end caps. However, this means that great care is needed while bending the leads or the end-caps may break and the resistor becomes noisy. I personally handmatched the Holco's. =) The opamps are each coupled at the feet with Sanyo Oscon capacitors. These are extremely low impedance and high ripple current capacitors and have massive filtering capabilities. I'd say they're better than even the best Blackgates for power supply purposes. The output jack is a Neutrik combi-jack. The reason for this choice is the feel of using the jack. My original intention was to use the Neutrik locking jack with gold-plated contacts. However, the excessive force required for it's usage put me off. The opamps used presently are OPA627BP's. The best low gain stable opamps from Burr Brown. This is the same as the BBamp Rev 2. However, they're not biased into Class A as heavily as the Rev. 2. The bias current for each opamp is maintained at a level where the sonic benefits can be reaped while allowing the opamps not to run overly hot to required cooling. Edit: I'm currently testing out AD843 opamps in the circuit. Preliminary impressions are that the opamps are about on par. There is a slightly different tone to each of the 2 but the amp remains very dynamic, neutral, musical sounding nonetheless. The AD843's however, run very hot (60'C) even with a low bias of 4mA per opamp. Right now, I believe it's just a matter of personal preference as to which opamps stay in the amp and get heatsinked! Edited August 28, 2004 by Firefox Share this post Link to post Share on other sites
Goondu 0 Report post Posted August 9, 2004 nice! How long did the project take you? And how much was the damage? BTW where did you get the RCA from? Do they come in RCA plug format? Share this post Link to post Share on other sites
Goondu 0 Report post Posted August 9, 2004 Why not bias the opamp into Class A?? 627BP! drool.... Share this post Link to post Share on other sites
Firefox 0 Report post Posted August 9, 2004 nice! How long did the project take you? And how much was the damage? BTW where did you get the RCA from? Do they come in RCA plug format? Inclusive of whatever R&D from the start. It took over a year. The RCA's were bought online. They're S$43.00/ pair. Vampire does have the equivalent 800C male RCA plugs. You can do a rough estimate: Holco's sell for US$0.60 a piece online. I bought 40 pieces for each value needed to match. The Noble pot is S$50 at Well Audio Labs. The Augat switch I used for power is US$12+ at Welborne Labs. Teflon insulated silver wire sells for at least US$2.40/ foot online and that is only 4N. Not the 5N stuff I used. The Vampire RCA's are S$43/ pair. So on and so forth. Why not bias the opamp into Class A?? 627BP! drool.... They're bias into Class A. But not as insanely heavily as the 2nd revision. Biasing opamps into Class A improves their sonic performance. However, as the bias current increases, the heat dissipated in the opamp increases too. As the opamps run hotter, their sonics become worse. So they would need heatsinking to allow high bias currents while not running too hot. In this case, I opted to use a lower bias current where it only runs lukewarm without need for heatsinks. This lowered current is still sufficient for my listening volumes. Share this post Link to post Share on other sites
N@Z 0 Report post Posted August 9, 2004 We definitely need a Meet now! I miss your notched volume knob! Moved to the DIY forum since technically this isn't a Mod but a DIY amp built from ground up. Share this post Link to post Share on other sites
bpribadi 0 Report post Posted August 10, 2004 Wow... Wow... Wow... Very impressive! Nicely done And another 'wow' for all the 'expensive' components The soldering work for the Oscon near the Op-Amp is fantastic Where did you buy the Neutrik combi-jack ? Share this post Link to post Share on other sites
lekguan 0 Report post Posted August 10, 2004 Hey firefox nice stuff there. The PTFE teflon insulated 6N copper is it multistrand or solid core? Share this post Link to post Share on other sites
Rameish 0 Report post Posted August 10, 2004 Mr Firefox, Looks like you finally made an amp that's fit for my modded Rotel 855 (if you can still call it a rotel lol). I for one would like to compare V2 with V3. Nice work as always. Let me know when it complete with the Avel Lindberg. Share this post Link to post Share on other sites
Q00 0 Report post Posted August 10, 2004 Wow....v3 is out and with alot of improvements! I still remember that the v2 was a very capable all-rounder amp that matched well with several cans at the previous meet. I will certainly be wondering how well this one is an improvement over the last. Again, really good craftsmanship Firefox, time for you to enjoy the music now and maybe have a drink as well? Share this post Link to post Share on other sites
Firefox 0 Report post Posted August 10, 2004 Mr Firefox, Looks like you finally made an amp that's fit for my modded Rotel 855 (if you can still call it a rotel lol). I for one would like to compare V2 with V3. Nice work as always. Let me know when it complete with the Avel Lindberg. Ay hello... The Rev 2 was built darn long time ago! hehehe.... The Avel wouldn't make much of a sonical difference. Just build-quality that I seek in it. Share this post Link to post Share on other sites
Firefox 0 Report post Posted August 10, 2004 Wow... Wow... Wow... Very impressive! Nicely done And another 'wow' for all the 'expensive' components The soldering work for the Oscon near the Op-Amp is fantastic Where did you buy the Neutrik combi-jack ? You can buy the Neutrik Combi-jacks from Hung Brothers or from LHS. The PTFE teflon insulated 6N copper is it multistrand or solid core? It's solid core. Share this post Link to post Share on other sites
