Solid-State Power Amp Adventures

Discussion in 'Power Amps' started by Marvey, Jan 24, 2017.

  1. brencho

    brencho Friend

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    haha yeah i'm going to try the adaptor on the EAR 890 this coming week! i'll let you know how it goes, curious about gain and such, i'll try off the 4 ohm posts. it was no contest at marv's though, made jotun sound flat and dull by comparison.
     

  2. jelt2359

    jelt2359 Friend

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    The H20 is A/B. I doubt I ever go into class B mode with headphones.
     
  3. jelt2359

    jelt2359 Friend

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    Try the 8 as well!
     
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  4. Scott Kramer

    Scott Kramer Friend

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    ...Moved to Moby i2s
     
    Last edited: Feb 7, 2017
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  5. Marvey

    Marvey Loves sex and records

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    Pretty much my reference while I have it on loan. I actually redid the x-over and EQ on the Altecs / 12" so I could use the Hegel. Originally the Vincent had better synergy, but when faced with a better component such as the Hegel, you work things around for it.
     
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  6. Grahad2

    Grahad2 Almost "Made"

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    I do wonder how the Ragnarok fares in comparison to these amps, even though it's lower in power.
     
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  7. Marvey

    Marvey Loves sex and records

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    The Ragnarok is actually an extremely good amp (assuming you are running speakers with good efficiency). Not included in this comparison because I wanted to keep things apples to apples. Current rankings are below. I'd put the Rag in class B.

    CLASS A (I Gotta Feeling)

    Hegel H2
    Bright but a step above the rest. Extremely competent in all aspects of sound reproduction and actually exceptional in many areas: bass extension and texture, soundstage size and imaging precision, microdynamics, transients, and smoothness.


    CLASS B (Not Bad)

    Vincent SP-331
    Not in the same class as the above. Less refined, less precise, less extended, flatter microdynamic shading. Euphonic presentation from tube bloom for better or worse.


    CLASS C (Entry Level)

    Crest CA2
    Neutral. Meets basic competencies, but to channel @MikeMercer, I'm just "not feeling it" all the time.


    CLASS D (Dubious)

    NuPrime STA-9
    Insipid.


    CLASS S

    Sheng Ya SP-993
    Has its moments, but stupid hot and heavy. Harsh and flat. More competent than the A23 below, but also more annoying. Wife "hated" this, and she's not a hate kind of person.

    Parasound A23
    I'm not sure I would even use this for HT.
     
    Last edited: Feb 14, 2017
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  8. ultrabike

    ultrabike Measurbator - Admin

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    Sweet, simple and concise. I like.
     
  9. ohmaigulay

    ohmaigulay Friend

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    This bodes well for Vidar. Fingers crossed. Itching for a big boy amp but patience is key.
     
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  10. sorrodje

    sorrodje Carla Bruni's other lover - Friend

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  11. Dino

    Dino Friend

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    My power amps were stolen, and I am interested in getting a replacement this year. One of the amps that has caught my interest is an old Adcom GFA-555. I was driving Vandersteen 2Ci (also stolen) and will probably be replacing those with whatever is the most recent Vandersteen Model 2. I remember the original Adcom GFA-555 had the print magazines making the 555 seem like it was really special sounding. It was a Nelson Pass design.

    So with that interest, I have been searching the internet about the Adcom GFA-555. I came across a forum with a thread about this amp and Nelson Pass was one of the participants. He talked about designing the original version and Adcom changing his design with Adcom GFA-555 II. He was not happy with the changes Adcom made and did not want to be associated with any 555 after the original. I wish I remembered where I read this. I'll look around and post the link in an Edit if I find it.

    I ran an Adcom GFA-545 (bi-wired) to those Vandersteens and enjoyed the sound for several years before replacing it to try (successfully) bi-amping. The 545 was not a Nelson Pass design.
     
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  12. beemerphile

    beemerphile Friend

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    I remember that article as well. Nelson Pass likes simple circuitry and he thought that Adcom made it worse rather than better with their additions. The GFA-555 has advanced to the SE model now, so who knows what is in it. I owned two GFA-555 II amps that I had professionally re-capped because of their age. I enjoyed them for a couple of years until one of them lost a channel. I gave up at that point and swore off the vintage amp sauce. I now buy new power amps when needed. Buying new though, these are in a field with many contestants and I am not sure they stand out any more. When my Adcom died, I replaced them with a pair of NAD C275's that I thought were at least as good. I sold the NAD's and bought a Crown pro amp that I thoroughly hated because of its sharp clinical sound. It was quickly replaced with a single Emotiva Stealth SA-250 (the Sherbourn design) that is no longer offered. I'm still satisfied with the SA-250.
     
    Last edited: Mar 7, 2017
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  13. Daveheart

    Daveheart Facebook Friend

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    @sorrodje the original 555 and 555 II can be good amps, but I generally avoid the 555se and any of the latter production Adcoms. Their QA/QC and service took a sharp downturn after the sale of the company. There's always the chance that they're rebounded in recent years, but it doesn't look that way. Here's a thread discussing the current products over at Stevehoffman.

    @Dino the older versions you've mentioned are certainly worth a look. I've mentioned it here before, but the 555, 555 II, 5500, and the 5800/5802 perform pretty well, esp. for US used prices if they're well serviced and biased toward the upper end of their tolerance. If you don't have a problem with doing a re-cap and are comfortable adjusting your own bias every once in a while (or you have a good service tech. who won't gouge you), then there's no reason to avoid them. They contain a lot of push connectors, so a good all around contact clean is necessary before making any bias adjustments. If servicing is a problem, then there's probably better buys out there.
     
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  14. sorrodje

    sorrodje Carla Bruni's other lover - Friend

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    Thks for all inputs guys . much appreciated :)
     
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  15. Tim Thomas

    Tim Thomas Friend

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  16. dBel84

    dBel84 Friend

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    I had picked up an ADCOM GFA5200 to keep me in music while I was messing about with recapping the Linn and then transitioned it to work . It is also a NP design, single mosfet output device , low stock bias to run about 1W class A . There are a few threads on moddifying these amps to get 20W classA with primarily adding power supply capacitance and smoothing as well as more heatsinking for the output devices. Stock it is a little on the warm side for my preference but not bad sounding.

    The build quality is solid - big torroid, decent stock heatsinks. Worth a look at considering how cheap you can find them. Mine was ~ $200 in it's original box.

    ..dB
     
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  17. fraggler

    fraggler The Cable Guy - Friend

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    Thanks for the suggestion! I read up a little more online about this model and decided to go for it. Got one on ebay for $105. Here's hoping it arrives in good working order. Pretty excited to hear how it differs from my little class D amp.
     
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  18. dBel84

    dBel84 Friend

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    Did you find that thread on DIYA that goes through the mod process?

    I am most likely going to end up modding mine, I had almost given it away as it was collecting dust in storage but this discussion piqued my interest again and has inspired plans to mod it.

    ..dB
     
  19. fraggler

    fraggler The Cable Guy - Friend

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    I did based on your comments, and funnily enough, someone referenced the DIYA thread in an ebay review of the amp as well. I probably won't be able to avoid tweaking it at some point. Please share your experience if you go through with your mods.
     
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  20. Crashem

    Crashem Rando

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    Is this the thread?

    http://www.diyaudio.com/forums/solid-state/5280-adcom-555ii-nelson-pass.html
     
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