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Gieseler Audio

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Gieseler Audio last won the day on August 31 2017

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  1. Gieseler Audio

    Power supply upgrade for Gross, Fein & Klein III DAC’s.

    OK - just finished listening to a brand new Klein III with std external transformer/plugpack vs a Kraftwerk M18 12v 4A PSU. OMG! what a difference - I did it five time with different tracks - it is a night day difference - everything gets better with the Kraftwerk PSU. Now I know everyone thinks sure he is going to rave a about it obviously as he makes them - but honestly there is a serious jump in sound quality that is dead easy to hear on repeated tests. Listening on the normal plugpack you think yes that all sounds good then you change to the Kraftwerk PSU. What the heck just happened! All of a sudden the instrument just sound way more real - veil removed - separation between everything is way better etc etc. Anyway I know a couple of Klein III owners who can do some independent evaluations so I will try & get that happening ASAP.
  2. Gieseler Audio

    Power supply upgrade for Gross, Fein & Klein III DAC’s.

    Yes I agree - Gross stays the same & the DC PSU is a simple upgrade path. I'm really keen to try the DC supply with a Klein III - almost finished building one so I will post the result here soon. I expecting it to make big difference as the Klein III is very basic so should benefit big time.
  3. Gieseler Audio

    Power supply upgrade for Gross, Fein & Klein III DAC’s.

    Matt - that is a very good point as the internal rectifying diodes are unnecessary when feeding the DAC DC. However they do provide a psydo form of galvanic isolation between the various sections. What I might try is runing the DAC chip & Amanero board sections directly from the 12v 4A supply but leave the bridge rectifiers in place for the micro processor & display sections. These two sections generate a fair amount of noise so leaving the bridge rectifiers on them helps add a bit of isolation. The plan is to leave the Gross design as it is so it will run from the external transformer & as an upgrade later the DC supply can be added. In the mean time I will test a Gross with the 12v 4A DC PSU built in & with the above diode mods in place. I have actually already designed a larger board like this so I will have a working version in a few weeks. With the bigger board it also gave me enough room to add independent left, right supplies for the analogue section of the DAC so that should add extra separation. It makes sense for some buying a new Gross + DC PSU to have the option of buying a fully intergrated version instead. How about “Uber” version. The boards I have coming are for the USB only version & if it sounds as good as I expect I will do a 3 - input version. A rough costing estimate is $2750 on the USB only & $3000 on the 3 - input version. Jventer - yes it is exciting finding a new upgrade path like this & the bonus is previous owners can benifit from it as well.
  4. Gieseler Audio

    Power supply upgrade for Gross, Fein & Klein III DAC’s.

    The Gross doesn’t actually draw much current, even playing high rez files it is less than 500 ma so it is a bit baffling as to why the original 2A transformer plus very good internal regulators can be improved upon. However In comparison the transformer used in the 12v 4A Kraftwerk PSU is a bit of a beast with a rating of 12v at 6A so the output impedance would be much lower. Also it is fully immersed in potting compound hense vibration levels would be very low. So now we have a situation where DAC is being supplied with a very stable well regulated low ripple DC supply so it is a much easier job for its internal regulators. I know it sounds like total overkill but at the end of the day it is all about the sound & it is very easy to hear the difference.
  5. Gieseler Audio

    Klein III owners thread

    Just a quick update. I ordered the boards today for the coax/optical only version. I should have finished stock in a couple of weeks. Will update with some photos then.
  6. Gieseler Audio

    Power supply upgrade for Gross, Fein & Klein III DAC’s.

    custom_made - yes I’m pretty amazed at the difference the big DC PSU makes. I will definately be keen to recompare the Gross to a couple of DAC’s which it could not quite match before. Might be a different story now. Jeddie - Sorry no all the Klein I & II’s will only work on AC.
  7. Gieseler Audio

    Power supply upgrade for Gross, Fein & Klein III DAC’s.

    Actually John I think you will be okay. Yours did to come back to me for some work and I’m pretty sure I upgraded it to the photo MOSFET relays but anyway I’ll check my records on Monday. I have a feeling you’re good to go though. 😀
  8. Gieseler Audio

    Power supply upgrade for Gross, Fein & Klein III DAC’s.

    For any Gross owners wanting to do a quick check to see if it will suit a DC PSU. Remove the lid & see if there is a blue power transformer on the board. If so it is Unsuitable. However I will be offering a modification service on the early versions to make them suitable for DC operation by changing them over to the photo MOSFET relay system. A bit of time involved as the pcb has to be fully removed - negative bias parts removed or disabled, transformer disconnected & photo MOSFET retro fitted. I would think $200 would cover it & that would include return freight.
  9. Gieseler Audio

    Power supply upgrade for Gross, Fein & Klein III DAC’s.

    All new Gross, Fien & Klein III's will run on AC or DC AC 9v DC 12v - 15v Std 5.5m 2.1mm power jack input. The only exceptions are the special active versions of the Gross & Fein DAC.
  10. Gieseler Audio

    Power supply upgrade for Gross, Fein & Klein III DAC’s.

    Hi Matt, no - it does bump the price up so all models will stay the same but the new PSU upgrade will be a permanent option. A bit like the way Naim does it. When time permits I will probably do a Uber version of the Gross & Fine that run directly from the big 12v AC 6A transformer.
  11. Gieseler Audio

    Power supply upgrade for Gross, Fein & Klein III DAC’s.

    Hi naggots, thanks for the vote of confidence - I will be staggered if you aren’t impressed. OK I will check out your serial number model etc at work tomorrow & let you know. RE Amanero femto upgrade Unfortunately I’ve run into a few snags with that. However with the new power supply upgrade I don’t think you would bother wanting to do anything else as it really does sound that good
  12. Hi everyone - well I have just made a very interesting discovery regarding the power source for the Gross, Fein & Klein III DAC’s. Purerly on a whim & at the suggestion from some knowledgeable people I decided to run a Gross DAC from my new M18 Kraftwerk 12v 4A PSU. What! - as you all know I’ve been telling everyone for years all my DAC’s run on AC not DC so why would I be trying this. Up untill recently all my DAC’s needed + & - internal voltages & the only way to do this is run them from a AC supply. With the Gross & the new transformer output design it eliminated the need for negative supplies except for one small negative bias supply for the muting transistors. Then about ten months ago I changed the muting system to a new photo MOSFET relay setup. NOW all of a sudden the Gross only had positive internal supplies so the feasibility of runing from a external DC PSU was entirely possible. But why would I try this? I go to a lot of effort with the internal PSU’s so I’m confident they are very good & I had already tried a much larger external transformer wth no sound change. As I said before it was purely on a whim & was not expecting any sound quality change OMG - I was totally gobsmacked at the sound improvement - I thought this can’t be right so I did the comparison another half a dozen times - same result! Then I tried it the next day & then a few days later - the result was very conclusive that the big external DC PSU was significantly improving the sound. OK time to see if any one else agrees so I asked a experienced Gross owner & a Fein owner to do the same comparison - conclusion - both agreed on the sound improvement. Now 12v is not the ideal external dc voltage due to the voltage drop from the DAC’s internal bridge recifiers but it is safe & works very well. My next step is to modify the 12v 4A unit for 14v output which will be the optimised voltage for all the DAC’s internal PSU to work correctly. While I’m at it I thought I would also try replacing the single main filter cap with a bank of 18 Silmic II caps which should improve things even more. However the Silmic caps are about $5 a pop so that option will bump up the price quite a bit. OK so at this stage I will doing a 14v version of the 12v 4A M18 Kraftwerk PSU especially to just suit the Gross, Fein & Klein III - cost $375 - the same as the current model. Plus a new pure Silmic II version at $500. I will order the boards tomorrow so about two weeks away. Guys I’m so confident about this upgrade that all units sold will automatically come with a return for refund in seven days option if not completely satisfied. IMPORTANT! Please no one try runing their Gross DAC’s on a DC supply untill checking with me first that their unit is compatible. Approximately the first fourteen Gross DAC’s are unsuitable due the negative internal muting bias supply. It is possible for me to upgrade those units to the new photo mosfet relays so then they would suit the new DC PSU. I will work out a costing on that soon. Exciting times!
  13. Gieseler Audio

    PDX DAC project

    Hey Ben you should hook the DAC up to your nice Tektronix scope - play some square waves & then you can see the effect of the filters.
  14. Gieseler Audio

    GIESELER Groß DAC official release

    als, I think the AK4497EQ DAC chip (used in Gross) works exceptionally well at decoding native DSD files. There is even a optional DSD vol bypass mode that totally bypasses the Delta-sigma section of the DAC. However the results with PCM material is also excellent. I think with critical listening DSD can sound a little better but it totally depends on the source/encoding of the track used. Max Headroom - excellent overall summary
  15. Gieseler Audio

    PDX DAC project

    So how does it sound vs the previous Amanero board?