Goldpoint SA1X and SA2X passive attenuator technical measurements

Discussion in 'Portable and Other Gear Measurements' started by atomicbob, Jan 6, 2019.

  1. k4rstar

    k4rstar Done his time

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    it sounds like you want an active monitor controller and not a passive one. how long are your cable runs?
     
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  2. Chris david

    Chris david Rando

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    Thanks, I hear you, and do understand that.

    That's also what I understand (straight from Glenn Coleman) but... lets say more so "just sonically speaking"
    ...there's definitely "some" kind of impactful (to my ears of course) information that's changing via the Coleman or, for that matter, A high quality Imperium 2400 controller I tried as well as well.
    Again, improved clarity up top to a degree, & better L-R imagining / tracking but still... I'm missing some the the "girth" that I hear directly from the Convert 2 direct to amp / monitors. Albeit at a cost of low volume L-R imbalance to a degree.

    I should also say that the Coleman M3 I've had here is an older version which has a 23 step Elma as opposed to the newer units 47 step Elma. Glenn assured me however, there's no actual sonic difference otherwise.

    I am curious to try the Goldpoint though.
     
  3. Chris david

    Chris david Rando

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    Interesting but, cable runs are only 3 feet from Convert 2 to amp/monitors or, 6 feet when having to go into the amp via a monitor controller.
     
  4. k4rstar

    k4rstar Done his time

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    okay, and what amplifier are you using downstream? i'm just curious. i hate to go all audiophool on you but the loss of balls or girth as you put it is what I generally experience with passive control solutions as well and sometimes it can't be explained by impedance matching, cable capacitance or attenuation loss. the input stage of the amplifier matters a lot in this regard. I would expect a similar case with the Goldpoint but unfortunately the good professional active controllers such as the Monitor ST are really expensive.
     
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  5. Chris david

    Chris david Rando

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    All very good points.

    I have Pelonis 4288 Monitors. They're very good but it's also true their included Class D amp, version 1 that I have is not super powerful. Their version 2 of the 4288 adds about 3.9 db more output. Hence, any less oomph via a monitor controller is not good in my situation.

    It is possible that impedance match with Convert straight to amp vrs via a controllers outs is where things are getting compromised. Though I'm not sure why that would be if that's in fact the case.

    I've have been considering the Monitor ST, but yeah it's much more pricey any overkill functionally for my modest i/o needs.
     
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  6. k4rstar

    k4rstar Done his time

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    ah got it, class D is a special case and it sounds like your particular monitor amp would like to see more voltage gain before the conversion to PWM. it seems like the designer realized this too and that's why he added 4dB of gain to the version 2. maybe the simplest solution for you would be to try to get that amp? or find a more modest, differential active pre-amp than something like the Monitor ST. on the low end of the market this will probably mean op-amps though. I don't have too much experience here to recommend any particular product, sorry
     
  7. Chris david

    Chris david Rando

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    I've been considering just getting the version 2 amp.
    It's bit pricey (of course) just for those extra 4 db but will consider.

    For now it seems either sit with the Converts potentiometer straight to the amp, or
    maybe try something active.
     
  8. atomicbob

    atomicbob dScope Yoda

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    The Convert-2 I measured was a loaner. I didn't acquire one for my lab. I own the original Coleman Audio M3 which has a very expensive matched 4 gang potentiometer, not stepped attenuator. When used between DACs and multiple monitoring systems I do not experience the degradation you describe.
     
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  9. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    For some time, I've used a JBL Nano Patch to attenuate devices going into my monitors. It's been totally fine. No complaints, really. But, I've always wanted to check out a Goldpoint attenuator. I finally found a Goldpoint SA2X-I (balanced, 2-in 1-out) on Reverb and saved a couple hundred bucks on one that shipped from the UK. It took forever to get here. The volume knob was loose and the top of the case had sun damage.

    I Plasti Dipped the top cover last night, tightened the volume knob, and measured it with the ADI-2 Pro. The bottom is off right now with its Plasti Dip curing.

    Every single position is perfect. absolutely no volume deviation, at least to the tenth of a decibel.

    And, it seems to be totally transparent. The JBL seems to make things not exactly rough, but slightly imperfect in comparison.

    This has already facilitated far better A/B comparison between DACs, including the Schiit Modius, Schiit Bifrost 2, RME ADI-2 DAC, and RME Babyface Pro.

    Thanks for bringing this outstanding piece of gear to my attention, @atomicbob. I wish I had this years ago when evaluating DACs much more aggressively.

    IMG_20200718_144040.jpg
    IMG_20200718_143601.jpg
     
  10. earnmyturns

    earnmyturns Smartest friend

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    I have a Goldpoint doing double duty of taming Yggdrasil balanced output and switching between two amps (EC Af and Phonotor XE). Not cheap, but clean and as this thread shows, high quality.
     
  11. Koth Ganesh

    Koth Ganesh Friend

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    Well, this does not help. The Yggdrasil’s outputs are not “hot” compared to those from the Convert 2 , Lavry DA 11 etc. I believe the question was whether the Goldpoint would tame the hot outputs of pro-DACs which is the question I have as well. It looks like 4:1 is the only way to go for now. I would love to stand corrected.
     
  12. earnmyturns

    earnmyturns Smartest friend

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    Yggdrasil: Maximum Output: 4.0V RMS (balanced), which is hot relative to some other consumer DACs. Convert 2 specs don't specify. Lavry DA 11 manual suggests a volume setting of 40 for 2V RMS (balanced) (page 16). With my Yggdrasil, I keep the Goldpoint at 7 out of 21 to keep the EC Af's pot in its midrange for comfortable ZMF Verité listening.
     
  13. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    I think you're talking about two different things. The Goldpoint isn't equivalent to an audio transformer like Jensen or CineMag, it's an attenuator. Basically, it's an external precision volume control. If you need to convert from balanced to single-ended, this won't do it.

    If all you need to do is attenuate a balanced signal so it isn't as loud, that's what this does. It can handle the RME ADI-2 Pro's +24 dBu just fine (which is louder than an Yggdrasil).
     
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  14. Koth Ganesh

    Koth Ganesh Friend

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    @earnmyturns , at 18 dBU, the Convert 2 has 6.15V RMS. But @Luckbad is right. These are different things. If the DACs are balanced and have super hot outputs into SE amps, look like the Jensens or equivalent are the way to go.
     
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  15. GoodEnoughGear

    GoodEnoughGear Evil Dr. Shultz‎

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    Very happy with my SW2X-I AND SA2X-O which give me 2 XLR IN switchable and 2 XLR out switchable with the 47 step attenuator. I had Arn add a third position to the output switcher (but still just 2 physical outs) which effectively gives me a mute position. That's my 'good enough' preamp.
     
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  16. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    My biggest complaint about the SA2X is that it has big jumps in volume for each turn of the knob. I didn't realize it at first, but that is intentional when low on the dial and, higher up, it's only 2dB per click. Most of my listening--even with -10dB on my monitors--takes place at 9 o'clock +/- 1 click (4-6 on the actual dial), and there are big volume jumps way down there.

    Goldpoint has recommendations to combat this with a pre-attenuation circuit: https://goldpt.com/preattenuation.html

    The most-recommended of the resistors for this purpose are IRC RC55, which are apparently transparent and are 0.1% tolerance. I ordered a set of them from mouser to attenuate the signal by 15dB extra (I was going to do 20dB, but adjusting for -20dB was just a little much for a few of my older recordings that are quieter than normal).

    What you do, essentially, is (on each of the four PCBs):
    • Desolder the IN wire
    • Solder Rp1 into the IN eyelet
    • Solder Rp2 into the IN eyelet and to the GND eyelet (should be doable with a little solder and no removal of the GND wire)
    • Solder Rp1 in-line with the wire and insulate it with heatshrink, teflon, etc. (I'll do an almost-NASA style join to make sure it's super strong)
    I emailed Goldpoint to make sure everything made sense before ordering the resistors. Arn was super responsive and thorough in his answers. Excellent customer service. I'll eventually get a single-ended stereo attenuator for my Project Sunrise when I decide which enclosure to use.

    I also asked what wire Goldpoint uses because it's really stiff and heat resistant. Apparently it is 22 awg silver coated stranded wire with Teflon jacketing. I'm going to source some of that for other projects (shouldn't need any new wire for the pre-attenuation circuit).
     
    Last edited: Jul 27, 2020
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  17. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    Photo attached of a 15dB pre-attenuation circuit I added to my Goldpoint SA2X-I. The wires and resistors were twisted together for a strong bond then soldered and heat-shrinked. I added a short Teflon sleeve between R2 and the GND connection just to be 100% sure it didn't touch the Out.

    I used IRC RC55 resistors at 0.1% tolerance so I didn't make anything go out of whack, and the measured attenuation is perfectly aligned at every position.

    Not the cleanest soldering job ever in part because I was nervous about leaving the iron on the PCB for too long (nearby plastic and SMDs), so there's a bit more solder than I wanted. Still works out well.

    IMG_20200722_170157.jpg
     
  18. Chris david

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    I've been so busy mixing I continued to use the Convert straight out but, "Still" considering picking up a Goldpoint attenuator to live between the Convert 2 outs and my monitor amp.

    Does this, or elsewhere in the thread imply the Goldpoint SA1X or 2X might not be a be fully able to "deal with" being able to reproduce downstream the Converts full 18dbu ?

    My main issue is the Convert (at very low monitor levels) does become troublesome with clear L/R staging imbalance.
    That, and although I've never been able to find an attenuator to live between the Converts outs and monitor amp that doesn't compromise, or subjugate the Converts Full bodied extension (& full 18dbu output) ...
    I'm also painfully aware that there was "a real clarity gained" when I used for example, the 2400 audio controller.
    Shame there was such a db and body loss with that one.

    ie; Still hunting for a reasonably priced and most important, compatible solution.
     
    Last edited: Sep 20, 2020
  19. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    It was able to handle +24 dBU without any noticeable issues for me.
     
  20. squishware

    squishware Friend

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    I recently acquired the Goldpoint SA1X (47 step) used from pure5152. I run the pair of JBL 305P MkII, 310S and Laptop full volume and attenuate only with the Goldpoint. It sounds much better than it did directly wired from the Bifrost 2. I assume because the amps are running full capacity and the 3 volume pots on the powered monitors are less active in the circuit.
     
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