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High Rollers
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About Vortex

  • Birthday 09/29/1967


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    Business Analyst (Former Electronics Engineer)

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  1. Thanks for the note on the Dynahi power supply board, Kevin. I just wanted going to ask you about that resistor labeled 40KDT (40K for dual tracking). There is also another resistor on the power supply PCB labeled 10KLO (on the negative rail section), which I couldn’t find in the schematic. (I’m using the schematic you have posted ). Also, The value of R15 on the schematic is 10K. To my opinion, R15 = R5 = 20K ? (correct me if I'm wrong or overlooked something)
  2. I have not tried it out yet (will do soon), but I think that LCDuino will have no problem with KG attenuators. For the processor, it’s just an 8 bits relay-based stepped attenuator (like any others from the same family). Only point that needs attention is the 12V PS for the relays on KG attenuator boards.
  3. To keep things simple, I will go for something relative cheap and easy to get. Probably this one or… this one. Both are made in Europe, so shipping cost is not a big issue. The Dyna PCB’s are designed for this kind of enclosure.
  4. Has anyone started stuffing (or touching ) the Dyna PCBs yet? I was busy today and this is what my boards now look like. The small things on the back are stacked KG stepped attenuators (for balanced use) and a LCDuino-1 processor. Still lots of (case)work to do...
  5. Thanks gents, much appreciated!
  6. One little note about the parts list for the power supply board. As most of you already know, the PS board consists of a ±30VDC section and a lower voltages (3.3V, 5V and 12V) section. The ±30VDC PS is used by the Dynahi. The lower voltages are only necessary if you are going to use relay-based stepped attenuator (for example: KG stepped attenuator or AMB δ1 stepped attenuator…). Otherwise you can skip the lower voltages section. More precisely, the following parts can be left out of the PS: Bridge Rectifier for 18V AC section LM7805 - 5V regulator LM7812 - 12V regulator Murata 3.3V DC converter 1x 4700uf/63V capacitor 3x 1000uf/25V capacitors
  7. You are correct that the final Dynahi PCB is a bit different than the layout under that link. The PCB indeed has place for 6 capacitors: 3 on the positive rail and 3 on the negative rail. These are local filter capacitors, the amp will work fine with 1 or 3 capacitors on each rail. Since the amp is feeding by ±30V DC rail voltages, the used caps need to be rated at a higher voltage than 30V. Capacitors rated at 35V (minimum) or higher (50V, 63V) can be used, as long as they fit the board. Some examples of 470µF capacitors are: Panasonic FM (Digi-Key P12400-ND) Nichicon HE (Mouser 647-UHE1J471MHD) About spending on higher quality parts, there is no general answer for that. For the active parts (transistors/JFets), you have to follow the specified parts (or alternative parts in some cases). For the passive parts (resistors, capacitors, volume pot…), one can go for boutique parts, but as long as they fit the board of course. (things you have to find out yourself)
  8. I have updated the first post with a BOM including Mouser parts numbers for the not yet specified parts in the preliminary BOM posted by Lil Knight earlier.
  9. Now that the PCBs are finding their ways to us -Balanced Dynahi Builders-, I think that it's time for starting a build discussion thread for this beloved amplifier. The purpose of this thread is to create a place for builders to discuss all topics related to the build of this amp (parts, constructions, troubleshooting...), to share experiences and to consolidate the information and discussions about this project. Schematics of the Balanced Dynahi and the associated Power Supply by KG. Background information about the original KG Dynahi can be found here. Based on the preliminary BOM posted by Lil Knight earlier, an updated version for the Dynahi and the associated power supply, including Mouser parts numbers for the not yet specified parts in the preliminary BOM can be found in the attachment. For the resistors, Vishay-Dale alternative parts numbers are added for people who like to use Vishay-Dale resistors. Happy building. BALANCED DYNAHI_BOM.xls
  10. My boards arrived in good shape. Thanks Kerry!
  11. This is very nice. Thanks for the efforts KG. I am in.
  12. I spot a pair of Sowter OPTs on the pic with multiple separate secondary windings, configurable for different headphone impedances. Probably (one of) the major different comparing to the original Menace which was OTL.
  13. As digger945 said, I'm using the GB through hole boards. Thanks for the link to the schematic, btw.
  14. This is my first post at this place, thanks for letting me in. I have been reading through this thread in the last couple of days. The efforts and collaborations of some DIY-ers here to bring this excellent project to the point we are now is very inspirational. It’s good to see the first assembled PCBs are alive and kicking. Keep up the good works! As some of you (Scott & Marc) know, I’m working on a balanced DynaFET too. In order to properly understand the electronics circuits, I was trying to find the (final) schematic of this amp but I couldn’t find it in this thread. (Hopefully I have not overlooked something). Much appreciated if someone can help me with this. Thanks in advance !
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