Audionote kit7/12/2023 ![]() It’s absolutely brilliant that ANK can leverage Audio Note’s engineering and parts development for DIYers, who can thereby approach the AN sound at a lower price point. By 2014, after many regular engineering trips from Canada to the UK and lots of AN part purchases, the kit business was taking on a life of its own, with a full range of products including E元4, EL84, and 300B amplification, phonostages, preamps, and DACs. To avoid confusion, the branding was changed to ANK or ANKits. It was then that Brian Smith approached AN’s president, Peter Qvortrup, with a proposal to keep the kit business going, and the end result was. But while originally the kit business was integrated with AN’s finished-product side, in 2004 it was shut down internally due to the support-heavy requirements and low margins of kits. Yes, this is an Audio Note UK (AN) design. Well, to be more specific, my report is strictly about the sonics of this DAC since I purchased the unit fully assembled. Since the SRPP is biased to about 8.5v, I would suggest an input signal of not more than 8.5/14.5 ≈ 0.586 Vpeak or ≈0.415 Vrms.T his is a rare bird in the pages of TAS-a kit report for the intrepid DIYer, who’s in search of an affordable DAC and not afraid of wielding a soldering iron. So depending on your input voltage and your volume setting, you could be overdriving the SRPP. The other thing to look for is overdrive. This may or may not be your problem, but it is an error on the schematic. To get this lift, based on schematic values, R2 needs to be about 109kΩ, not 87kΩ. This is right at the limit for both the upper and lower triodes. With the voltages in this circuit, you want that heater lift to be about 108v. The cracking you're hearing could be heater-to-cathode breakdown in the SRPP. With the upper cathode at ≈208v this puts the differential at 208-85=123v. It should be around 85 volts according to the schematic, However, according to the Tung-Sol and Raytheon data sheets, the maximum heater to cathode differential is +/- 100v. So inspect all the joints to make sure they all look ok.Īfter that, in this design, look at the heater lift for the 5687. If there are crackling noises in an amp, the first thing I look for is cold solder joints. The louder the music the louder are the cracking noises.Are the cracking noises in one or both channels? Otherwise only one of the two triodes will be heating up.Ī picture of the circuit boards, both top and bottom, would be helpful as well.įirst thing there are cracking noise in the speakers when the music is playing especially around the bass. For this to work properly pins 4 and 5 should be shorted together and the 6.3v winding connected to pins 4/5 and pin 8. The heater is marked as pin 4 and pin 8 on the tube, but the note on the transformer winding say 4 and 5 on the 6.3v winding. There is also something on the schematic that is unclear. But a common problem with some circuit boards is that the tube socket gets soldered to the wrong side of the board. Now I'm going to suggest you check something and I don't want you to take offense. If it's happening on both channels there is a more systemic problem. You were not clear as to whether this was happening in one or both channels. The second clue is that your grid voltage on the upper triode (pin 2) is essentially the same as the plate (pin 1) and I assume the cathode voltage (pin 3) as well. ![]() The only way this can be is if there is no current through R17. What this means is that there is no current flowing in the SRPP stage.
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