The Adcom GDA 600 modification thread

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  • FTGV
    FTGV Posts: 3,649
    edited May 2010
    Poee7R wrote: »
    Due to logistics, George you would probably be best option,.
    Agreed Dave,and I'm sure George will take good care of your baby.:)
    george daniel wrote: »
    Guys just remember,when attempting this mod,, "never get out of the boat";)
    Good advice and I'm curious as to how the cap got into the resistor location on davide256's PS board.:confused:
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  • davide256
    davide256 Posts: 50
    edited May 2010
    Ok, that seems to be it. Putting the spec resistor in R113 totally eliminated the hum and volume knob transients with the working op amp inserted in right channel, sticking one of the blown op amps in the left stopped the volume knob transients there also with no hum either channel until max volume. will order another op amp and keep my fingers crossed.
    As to why the capacitor where it shouldn't be, its bizarre... it was an original part like a dozen others on the two boards.
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  • FTGV
    FTGV Posts: 3,649
    edited May 2010
    davide256 wrote: »
    Ok, that seems to be it. Putting the spec resistor in R113 totally eliminated the hum and volume knob transients with the working op amp inserted in right channel...
    Cool,so you just happened to have 3k32 resistor on hand?:)Did you recheck to be sure the voltages were +- 15 VDC?
    As to why the capacitor where it shouldn't be, its bizarre... it was an original part like a dozen others on the two boards.
    Interesting,I guess it got missed in QC and the stock opamp must be able to handle the higher supply voltage.
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  • Poee7R
    Poee7R Posts: 904
    edited May 2010
    Ok Im getting ready to order some parts. As Im looking through PartsX, they have the previous gen Burson discrete available at just over $100 for a matched pair, which would be the same as the BB's.

    http://www.partsconnexion.com/bbs_digital_semi.html

    Would these be worth considering, or am I jumping head first out of the boat? haha


    Dave
    Once again we meet at last.
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  • FTGV
    FTGV Posts: 3,649
    edited May 2010
    Well your atleast getting your feet wet.:)I would expect them to be excellent but using them would require a couple of other changes. Aswell I think the hi slew rate of the BB would make it the better choice for the I-V half of the output circuit while the Burson might have the edge in buffer half of the circuit. Unfortunately the 600 uses dual opamp packages so you can't easily mix and match both types.Besides both George and H9 report excellent results with the OPA627.
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  • Poee7R
    Poee7R Posts: 904
    edited May 2010
    Roger that.

    Ill stick to the plan.


    Thanks Fred,

    Dave
    Once again we meet at last.
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  • dacboy
    dacboy Posts: 23
    edited May 2010
    davide256 wrote: »
    Ok, that seems to be it. Putting the spec resistor in R113 totally eliminated the hum and volume knob transients with the working op amp inserted in right channel, sticking one of the blown op amps in the left stopped the volume knob transients there also with no hum either channel until max volume. will order another op amp and keep my fingers crossed.
    As to why the capacitor where it shouldn't be, its bizarre... it was an original part like a dozen others on the two boards.


    Duuuuuuude you are soooooo lucky you didn't fry your DAC. Seriously you need to be thanking the audio gods.. ;)
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  • heiney9
    heiney9 Posts: 25,193
    edited May 2010
    dacboy wrote: »
    Duuuuuuude you are soooooo lucky you didn't fry your DAC. Seriously you need to be thanking the audio gods.. ;)

    It wouldn't have been his fault. Looks like his dac came with a factory error, no way he could have predicted that. Just a bizarre set of circumstances and it seems the stock opamp worked, we're just not sure how well. :)
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • george daniel
    george daniel Posts: 12,096
    edited May 2010
    Okay--I've got them ordered--I'll post a play by play pictoral of this one--I promise (right after Fred talks me thru it):)

    Are you ready ;)
    JC approves....he told me so. (F-1 nut)
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  • george daniel
    george daniel Posts: 12,096
    edited May 2010
    Poee7R wrote: »
    Roger that.

    Ill stick to the plan.


    Thanks Fred,

    Dave

    Yep--never get out of the boat--seriously,please use the browndogs,as I have zero experience with the burson op-amps--however if you have to use em,them, then I would insist that you send yours to Ben or someone else,because I do want to be responsible for "cooking" them.Thanks.:)
    JC approves....he told me so. (F-1 nut)
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  • heiney9
    heiney9 Posts: 25,193
    edited May 2010
    george daniel wrote: »
    Okay--I've got them ordered--I'll post a play by play pictoral of this one--I promise (right after Fred talks me thru it):)

    Are you ready ;)

    Yep, I'm ready. I'll get them ordered as well. :)

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • george daniel
    george daniel Posts: 12,096
    edited May 2010
    Guys,, I'll get a complete inventory of all of the parts together and try to get it posted,,for now here are the opa's and the film caps from Socicap

    Browndog---OPA 627-020302S from cimarron tech,,you'll need 2 @ 49.00 each
    Sonicaps 2 of each below
    0.0027/600vdc
    0.0039/600vdc
    0.022/600vdc
    JC approves....he told me so. (F-1 nut)
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  • heiney9
    heiney9 Posts: 25,193
    edited May 2010
    george daniel wrote: »
    Guys,, I'll get a complete inventory of all of the parts together and try to get it posted,,for now here are the opa's and the film caps from Socicap

    Browndog---OPA 627-020302S from cimarron tech,,you'll need 2 @ 49.00 each
    Sonicaps 2 of each below
    0.0027/600vdc
    0.0039/600vdc
    0.022/600vdc

    I'll also add as an alternative to Sonicaps you can use Multi Cap PPFMX here:

    http://www.partsconnexion.com/capacitor_film_multicap_ppmfx.html

    Not trying to make it more complicated but these two brands are among the only pieces that will fit as the axial leads need to be very small.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • FTGV
    FTGV Posts: 3,649
    edited May 2010
    george daniel wrote: »
    Okay--I've got them ordered-
    When they show up can you scan the enclosed lit sheet and email it to me?thanks.

    I'm not sure what level of improvements you guys can expect from these but feeding the opamps from a clean source of DC is always a good thing,IMO second most to the quality of the opamp it'self. I have used similar regulators in some of my projects with positive results with improvements mostly in the areas of dynamics and detailing .
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  • george daniel
    george daniel Posts: 12,096
    edited May 2010
    Yep on the scan and e-mail.I'm gonna dance with what brung me(Paul "Bear "Bryant).
    JC approves....he told me so. (F-1 nut)
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  • heiney9
    heiney9 Posts: 25,193
    edited May 2010
    George,

    Did you get 50% off your Burson regulators? Only reason I ask is I received an e-mail fro Parts Connexion stating they have 50% off the old style shunt regulators but when I go to the site it states 25% off.

    Just wondering

    H9

    http://www.partsconnexion.com/t/econnexion/0510/may10.html#burson

    About 1/2 way down the page on the above link which is straight from the email I received
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • Poee7R
    Poee7R Posts: 904
    edited May 2010
    Glad I checked the thread for the model numbers of the voltage regulators. I thought at 25% off it was a good buy, at 50% makes it that much better.


    Dave
    Once again we meet at last.
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  • heiney9
    heiney9 Posts: 25,193
    edited May 2010
    Well, I just ordered them.............sort of. They have to get back to me with a final price including shipping etc. They don't have a checkout system where you buy it instantly. Someone will get back with me via e-mail with my final out the door total so hopefully they are actually 50% off..........that's a great deal.
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • FTGV
    FTGV Posts: 3,649
    edited May 2010
    heiney9 wrote: »
    Well, I just ordered them.............sort of. They have to get back to me with a final price including shipping etc. They don't have a checkout system where you buy it instantly. Someone will get back with me via e-mail with my final out the door total so hopefully they are actually 50% off..........that's a great deal.
    Nice find, I would think they would obligated to give you the advertised price?Today is a holiday up here so you may not get a confirmation email until tommorow?At this price I might get a pair to try in something.
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  • heiney9
    heiney9 Posts: 25,193
    edited May 2010
    To furthur entice.

    http://www.tnt-audio.com/accessories/burson_regs_e.html
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • george daniel
    george daniel Posts: 12,096
    edited May 2010
    Yep I ordered them,, but i deleted the e-mail-- so I guess I'll have to re-submit--IIRC it was 60.00 for the pair.
    JC approves....he told me so. (F-1 nut)
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  • heiney9
    heiney9 Posts: 25,193
    edited May 2010
    george daniel wrote: »
    Yep I ordered them,, but i deleted the e-mail-- so I guess I'll have to re-submit--IIRC it was 60.00 for the pair.

    Hmmmmm....I received the email "flyer" on 5-21-10. I would think these would be more than a 1 or 2 day sale. Unless the "flyer" is incorrect, but they still should honor the price if one mentions the sale flyer, IMO. They are closed today because of Victoria Day in Canada so we'll see what they say tomorrow.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • Poee7R
    Poee7R Posts: 904
    edited May 2010
    Just received an email back and they are 50% off.

    Good catch H9.


    Dave
    Once again we meet at last.
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  • george daniel
    george daniel Posts: 12,096
    edited May 2010
    okay-- so the price for 2 is??
    JC approves....he told me so. (F-1 nut)
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  • heiney9
    heiney9 Posts: 25,193
    edited May 2010
    george daniel wrote: »
    okay-- so the price for 2 is??

    I'm still waiting to hear back from PC as they were closed yesterday. I would assume then it would be like 2 for 1 (at the regular price) plus shipping and tax. So $40 and shipping

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • Poee7R
    Poee7R Posts: 904
    edited May 2010
    Until I get my confirmation on my emailed order, Im assuming $40 for the pair.

    The cart still shows 25% off, so I emailed my order.


    Dave
    Once again we meet at last.
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  • heiney9
    heiney9 Posts: 25,193
    edited May 2010
    Poee7R wrote: »
    Until I get my confirmation on my emailed order, Im assuming $40 for the pair.

    The cart still shows 25% off, so I emailed my order.


    Dave

    Yes, they adjust when they send your order confirmation.
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • george daniel
    george daniel Posts: 12,096
    edited May 2010
    on the phone with them now-- I have a quote for two==59.90,,,ya'll?
    JC approves....he told me so. (F-1 nut)
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  • heiney9
    heiney9 Posts: 25,193
    edited May 2010
    george daniel wrote: »
    on the phone with them now-- I have a quote for two==59.90,,,ya'll?

    Did you mention the email? Ask them when the sale ends? I just got that email last Thursday.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • george daniel
    george daniel Posts: 12,096
    edited May 2010
    Well the guy says 50% off my initial 59.90--so I'm waiting to see what really happens--at this point I am really confused--but not complaining
    JC approves....he told me so. (F-1 nut)
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