George send me your DAC

heiney9

So George did you have to completely remove the PC boards to replace the Op-amps? Can you show me or detail which filters you bypassed and where they are?

Since Sonicraft has the 20% off sale I'm thinking about getting the Auricaps and getting going on this project.

H9

george daniel

Brock,, I am replacing/upgrading some of the power supply caps and a couple of bypass caps IIRC,, I am not going to need any sonicaps as I originally thought,, lemme' get thru work today and I'll post or pm what I did and will be doing.I did replace the op amps with the dual opa 627 browndogs,,then I removed and "jumped" to filter caps in the output stage(as it was suggested that they might MASK the flavour of the new op amps so to speak.I can say this,,currently,, it is very detailed,,not bright,,but not laid back anymore.I'll add more in detail this evening.

backsigns

I would like to see the details of your work, since I will be doing the same to my 600.

heiney9

TTT,

George how are the rest of the mods going w/all the suggestions from GV27? Do share, I'm waiting until yours is complete and then I'm starting mine, but I need the info, etc.

H9

george daniel

Brock and all,, I will be installing the rest of the caps this weekend as per gv's suggestions,, so far the mod has gone well,,fairly simple,,let me finish and I will post pictures and a review,,and with permission of gv,, a very easy step by step process which has really helped me.How does it sound with the new opa's? Fanatastic,, getting detail like I never had before,, so if you decide to do this after I post the final product,, don't rush out and buy the electrolytics,,as I'm gonna have a few extras.Just with the new op amps,it's a different machine,, for the better. YMMV

heiney9

Great news George!! I was at my buddy's last night with the schematic and the unit looking at which caps to replace. My thought was to replace the (6) three per op-amp yellow film caps with Sonic Cap Gen II's and the (6) PS caps. As well as replacing the Op-amps and bypassing what ever analog filter you and GV suggest. I have an idea of where it is but not sure.

I'll send you an email per your PM

Photo's and a step by step would be fantastic.

Thanks--H9

backsigns

george daniel wrote: »

Brock and all,, I will be installing the rest of the caps this weekend as per gv's suggestions,, so far the mod has gone well,,fairly simple,,let me finish and I will post pictures and a review,,and with permission of gv,, a very easy step by step process which has really helped me.How does it sound with the new opa's? Fanatastic,, getting detail like I never had before,, so if you decide to do this after I post the final product,, don't rush out and buy the electrolytics,,as I'm gonna have a few extras.Just with the new op amps,it's a different machine,, for the better. YMMV

Thank you so much! I am just about ready to begin this and your instructions and step by step would be fantastic! I only wish the 600 was capable of 24/96, I would then be soooo happy, but I can certainly live with it:D. My browndogs are on the way and when you post I can order the rest. Again, thank you for sharing this info with us!

george daniel

Here are the schematics
http://www.audiokarma.org/forums/attachment.php?attachmentid=33267&d=1165789198

Okay here we go

Replace op amps(I used the Browndog OPA 627 from Cimmaron Tech,, you can de solder and replace or use a DIP * adapter that allows you to roll the opamps like you would tubes,I just replaced mine with the Browndogs and soldered them to the board

Add 120uF caps 25 volt caps to i parrell to the .1uF bypass caps (c 528,529,530,531)at the power pins of the op amps Careful to mainatin proper polarity,these serve as local power reservoir's for the opamps.

Next--the all inportant 15 volt regulators that feed the analog section (OPA 627)Remove the 2 10uF caps (C100 and 104)and install 470uF 35 volt or larger(i used the 470/35v)

Replace the 2 .1uF caps at (C122 and C 123) with 22uF 25volt caps.This will increase the ripple rejection.

L550 and L 555-1 remove the inductors and jump them(it is felt that these ferrite inductors might mask the flavour of the op amps)

Remove the caps at C 550 and 551(just desolder and remove)

I ordered my caps from Digikey--get the Panasonic FC series

At first I felt the unit was not as "laid back" as before,,it was different,,in a good way,, very revealing,apparently accurate,very fast,,and overall,it just sounds damn good.If anyone is going to attempt this,,you will NEED a desoldering iron to remove the components,as they are small solder joints.Also make sure that you install the opa's correctly,,pin number 1 is usually designated with a marking of sorts,,and the corresponding pin on the browndog is the "b",in browndog,,if you are not sure,, call the manu. or shoot me a pm. I have some extra caps left over from my project,,if you need some,to do THIS mod,,pm me.I only wish the I had the talent to compose this mod in better format,,but I have to give thanks and credit to a former member GV-27 who hung with me,and stepped me thru this project.Up until now,,I never thought an external DAC could make such an impact in my system,,this has to be one of the least expensive/biggest bang for the few bucks spent mod I have ever done,,I'd rate it on the level of going from stock SDA crossovers to ones with sonicaps--huge impact.

If you attempt this easy mod,the biggest price impact will be the OPA's.If I can help,please pm or call me.

Thanks for reading this,,and thank you to GV-27,,I could not have accomplished this without you.

George

backsigns

Wow! You added a few things. I was going to replace all the electrolytics while I was in there anyway. Thanks for the instructions. I've already recapped my Carver C-1 pre and need to do my TFM-55. I will order it all at the same time and get to work (or play). It is very empowering to do this yourself. Can't wait to hear this thing!!!:)

heiney9

Fantastic George. Perhaps you could put it in list form and the schematic references are great and necessary!

I'll be ordering the Op amps on Monday or Tuesday. What do you have left as far as caps? Didn't realize Digi-Key had a minimum.

Thanks-

H9

george daniel

Don't order any caps,, I did not replace any of the film caps,as I am under the inpression that it would make a minimal sonic impact,, now with that said,,I may revisit it,, but not at the monent. It's all good.

megasat16

GV#27 is a Class Act there! Excellent Info from GV even though he is not with us anymore. Thanks GD for sharing the info.

george daniel

the op amps are circled in purple. When you renove the note their orintation,specifically the power pin( usually dsginated by a mark,logo,letter)-,then replace the new op amps with the proper orientaion of the powwer pin. Solder in place
Next the "ferrite conductore--circled in red are removed and replaced with jumpers. If you follow the instructions,you will not that each component has a corresponding number.Jusr br careful when replacing the electrolytics that you maintain prpoer polarity

george daniel

Wooooooooo Hoooooooooooooo,,oh Mama,, I'm done with it.Having owned a few DAC's,I can honestly say that I can hear a huge difference over the stock version.I have detail in spades,,it is also very involving in my rig.Ever notice that when you hear a really good system,how the music just pulls you in,,and you find yourself being a part of the performace/experience? Well,, thats what this mod has accomplished in my system.I'm running a 100 dollar Rotel 855 to the adcom,,then to the Belles 20a,, Quicksilver GLA 40-50 watt tube amp,then the 1C's with sonicaps and RDO's.I can honestly say that it has never sounded this good.I know I sound a little "giddy" ,,but to me it sounds that good.I would highly recommend performing this mod to you Adcom GDA 600 owners.I'll return and post a more practical approach to performing this mod now that I have completed it.I have learned a hell of alot along the way.Thanks for allowing me to rant about it.

heiney9

george daniel wrote: »

Wooooooooo Hoooooooooooooo,,oh Mama,, I'm done with it.Having owned a few DAC's,I can honestly say that I can hear a huge difference over the stock version.I have detail in spades,,it is also very involving in my rig.Ever notice that when you hear a really good system,how the music just pulls you in,,and you find yourself being a part of the performace/experience? Well,, thats what this mod has accomplished in my system.I'm running a 100 dollar Rotel 855 to the adcom,,then to the Belles 20a,, Quicksilver GLA 40-50 watt tube amp,then the 1C's with sonicaps and RDO's.I can honestly say that it has never sounded this good.I know I sound a little "giddy" ,,but to me it sounds that good.I would highly recommend performing this mod to you Adcom GDA 600 owners.I'll return and post a more practical approach to performing this mod now that I have completed it.I have learned a hell of alot along the way.Thanks for allowing me to rant about it.

Outstanding George, I eagerly await instructions from you so I can get mine done.

H9

engtaz

Congrats George