Rameish 0 Report post Posted November 25, 2003 (edited) This month has been hectic with work and family commitments taking priority. Firefox and I wern't able to meet up for several weeks prior to this and finally the itch to mod the humble Corda HA-1 (what is now called the MkI). The picture here is the stock corda so that you'll be better able to follow the modifications. All work was done by the Mr. FireFox aka DreamSlacker (A Big Thank You). The stock corda has four LM 6171 chips. 2 x Panasonic 16 V 3,300 uf caps and 2 x 35 V 1,100 SamWah caps. The red caps are Wima poly caps. This work in progress was inspired by Kurt W but certain differences exits. StockJPG Edited November 25, 2003 by Rameish Share this post Link to post Share on other sites
Rameish 0 Report post Posted November 25, 2003 Cascode Current source (FET) on daughter boards Share this post Link to post Share on other sites
Rameish 0 Report post Posted November 25, 2003 Op amp and buffer swapped - BUF 634 Buffer x 2 and OPA637 x 2 Share this post Link to post Share on other sites
Blues 0 Report post Posted November 25, 2003 something like corda blue? would love to see the progress. Do keep us updated rameish Share this post Link to post Share on other sites
Rameish 0 Report post Posted November 25, 2003 (edited) Schottky Fast Recovery Diode "bridge" three on top as seen and one below. Firefoc swapped out the 1,100 uf SamWah caps for Nichicon 35 V 4,700 caps and the Panasonic was swapped out for Black Gates 4,700 uf caps. The Heat sinks on the Buffers are there because the ultra high band width mode has been engaged on the buffer LOL. Edit: I had confused the 2 cons and the blue caps are Nichicon (1st stage in the PS) sorry for the mistake - I do get confused between rubycon and nichicon. The Black Gates are of course Rubycon. Edited November 26, 2003 by Rameish Share this post Link to post Share on other sites
Rameish 0 Report post Posted November 25, 2003 Close Up Share this post Link to post Share on other sites
Rameish 0 Report post Posted November 25, 2003 No blues I want to go further than the Corda Blue mods hence the name Corda HA-1 SE i (Sepcial Edition improved). Share this post Link to post Share on other sites
Rameish 0 Report post Posted November 25, 2003 Oh Firefox changed some of the resistors as well to Vishay Dales. Share this post Link to post Share on other sites
Rameish 0 Report post Posted November 25, 2003 Heat sinks and more Vishay Dale resistors replacement *I like the 120 ohm jack u see" Share this post Link to post Share on other sites
N3w_Typ3 0 Report post Posted November 25, 2003 (edited) wahaha ... how does it sound to you ? .. well let blues try out later if he finds this sound is more to his taste he may drop his idea of getting tube amp by the way this modded cost how much ?? Edited November 25, 2003 by N3w_Typ3 Share this post Link to post Share on other sites
Rameish 0 Report post Posted November 26, 2003 (edited) If you were to do these mods yourself it would cost approx S$250 in parts alone. I was lucky as I got some parts free - the op-amps (thank you ablaze). The BP grade of the op-amps are approx S$55 each (you need 2). The Buffers are S$17-S$18 from Farnell. The Black Gates were S$64 for a pair (from Well Audio Labs) and are really optional. Likewise for the Nichicon (edit) "blue". (BTW Kurt W mods do not include any changes to these elect caps). However my personal view is when you want to improve things you need to work you way up from the power supply. Next Step is to use up to 3 buffers of a slightly different type of 634 per channel on daughter boards (ala Corda Prehead). And maybe swap out the red wima caps for solens. Space is tight so I don't know if it can be done. As far as sound goes it's now more or less on par with the HA-2 (a little more detailed and a little less weight perhaps). I'll have to borrow a HA-2 and make a side by side comparison to be certain as I'm saying this from memory. It's been approx 2 weeks since the HA-2 walked out on me. Am I trying to create a Corda Prehead out of a Corda HA-1? You betcha! Will I be successful? Probably not. But hey It's gonna give it a run for it's money. My budget in parts would be up to S$300 - S$350 max bec anything more would be marginal as it would involve a transformer change to Avel Lindberg and a volume pot upgrade to either a Nobel of TKD...hmmm...maybe I'll do it LOL (S$70 - S$80 for the avel lindberg transformer and S$50 upwards for the pot). Muhahahahah Edited November 27, 2003 by Rameish Share this post Link to post Share on other sites
Barradio 0 Report post Posted November 26, 2003 Ramiesh, the TKD pot same size like the blue Alp is S$100+ and the small one that in the Headline is S$50 for your info. Share this post Link to post Share on other sites
jtfoo 0 Report post Posted November 26, 2003 What are the models for the Rubycon 'blue'? Share this post Link to post Share on other sites
Rameish 0 Report post Posted November 26, 2003 (edited) JT, Just standard Nichicon ones I guess I don't know for sure - firefox picked it up. Are there special versions of these? Barradio, looks like I've got to increase my budget LOL. Edit: The Blue caps are Nichicon and not Rubycon Edited November 26, 2003 by Rameish Share this post Link to post Share on other sites
jtfoo 0 Report post Posted November 26, 2003 Rameish, Just curious since you didn't mention themodel. Rubycon are generally used in audio, but I'm just not familiar which models are they. I've searched Rubycon catalog and coudn't find any caps they labelled as audio grade, and my only guess are probably those labelled as ultra low impedance that diyers used. I know Blackgates are made by them but strangely they are not in the catalog either. Share this post Link to post Share on other sites
