Maniac Posted January 21, 2009 Report Posted January 21, 2009 (edited) Hello everyone, (NOTE: Order before the end of Jan' 2009 and you will receive free IeGO GU-R301 socket upgrade! A $30USD value free! ) We are proud to announce KECES' first dedicated headphone amp/pre amp in the current product line-up. First of all, photos! Front angled view, as you can see the input select and gain select switch. The rest of the layout is just like DA-152. Front view, slightly more boring but shows the front more clearly. Rear view: Two sets of inputs, one bypass for your other amps and systems, and one pre-out to your power amp or active speaker. Basic specs: [*]High performance headphone amp with up to 250mA/channel capability. (that's a lot for most headphones in the market) [*]Even better than DA-152's headphone performance, with excellent detail, neutral tone with a bit of warmth, and great smoothness. [*]Two sets of selectable input for connecting to different sources. [*]One set of bypass output that, well simply bypass the signal from input with no additional processing. [*]One set of pre-out the is slaved to the headphone output, the test figure below shows what this puppy can do. [*]Independent power supply for pre-amp and control power. Reducing the possibility for interference. [*]High performance tuned regulator for pre-amp section. [*]Dimension: 215 Edited January 21, 2009 by Maniac add some notes and edit a bit of the layout.
Beefy Posted January 21, 2009 Report Posted January 21, 2009 *giggle* Keces is like Feces. In all seriousness, internal shots would be nice.
Maniac Posted January 21, 2009 Author Report Posted January 21, 2009 Will post some internal photos in a few hours, need to get my shooting rig setup so that I can take a more detailed photo.
grawk Posted January 21, 2009 Report Posted January 21, 2009 (edited) Miscommunication, you HAD gotten approval, my bad Edited January 21, 2009 by grawk
grawk Posted January 21, 2009 Report Posted January 21, 2009 Bump since I harrassed you when I shouldnt' have. My apologies.
mr.khali Posted January 21, 2009 Report Posted January 21, 2009 Will you be sending out a sample unit for an experienced member of the community to review?
Hopstretch Posted January 21, 2009 Report Posted January 21, 2009 That actually looks pretty nice. Is the top casing translucent like your DACs? And by "pre-out slaved to the headphone output" do you mean speaker output is muted when headphones are plugged in? Otherwise, I'll just echo Beefy's desire to hear more about what components are in the box.
Maniac Posted January 21, 2009 Author Report Posted January 21, 2009 Bump since I harrassed you when I shouldnt' have. My apologies. It's alright, thanks.
Maniac Posted January 21, 2009 Author Report Posted January 21, 2009 That actually looks pretty nice. Is the top casing translucent like your DACs? And by "pre-out slaved to the headphone output" do you mean speaker output is muted when headphones are plugged in? Otherwise, I'll just echo Beefy's desire to hear more about what components are in the box. The top is the same as the other's in using a translucent acrylic cover. Both output are always on, by slaved to the headphone output, I mean pre-out output the same volume as the headphone output. Innards view: To satisfy the pixel peepers inside all of us. Click for large 5 mega pixel photo if you REALLY want to see the details. Anything you'd like me to elaborate about on the photo? The relay in the back is for input select, and the one near the volume pot is for gain selection. Thanks
Maniac Posted January 21, 2009 Author Report Posted January 21, 2009 Will you be sending out a sample unit for an experienced member of the community to review? I'm certainly considering that, any recommended member? A few reviewers I had previously were less than ideal, some dragged on for 3~6 month, and some simply vanish not too long after they have decided that they'd like to keep the unit. I think neither me or the community would really want to see either happen, as it not only deter us from providing the review sample, it also deprive everyone the information that they had waited so long to see. Thanks David
Torpedo Posted January 21, 2009 Report Posted January 21, 2009 I think in this community you can trust any of the long term members, as much for their dependability as for their fine non-biased judgment. Probably it'd be good to wait until an interested one offers. The unit looks nice and tidy, congratulations. Has it to be ordered for specific AC voltage or can it work either at 120 or 230V?
spritzer Posted January 21, 2009 Report Posted January 21, 2009 As can be seen in the pics there is a switch on the back to change the input voltage.
Torpedo Posted January 21, 2009 Report Posted January 21, 2009 Now that you mention it, yes, the red one. I need a new set of glasses
spritzer Posted January 21, 2009 Report Posted January 21, 2009 Also if you checked the internal picture there are 4 wires leading to the transformer which usually means that the transformer works on the two systems.
Torpedo Posted January 21, 2009 Report Posted January 21, 2009 Ha, I didn't see the switch, so forget about the wires
Maniac Posted January 21, 2009 Author Report Posted January 21, 2009 We always check customer's location and pre-set the unit to the proper voltage, and include the proper power cable for the region. (We have American NEMA type, Euro Schuko type, Brit type and Aussie/Kiwi type of power cable in stock here...) We feel that including the cable is going to make it more convenient for most people, as for RCA/Coax/Toslink cables, we opt not to do so as most have their own preferred cable.
MASantos Posted February 3, 2009 Report Posted February 3, 2009 Nice layout and internals! Just one question? Why isn't the output 1/4 jack mounted inthe same blue PCB? Just curious. Can you share a bit more about the basic topology? It looks like opamp input stage followed by a discrete output stage? Mosfets under that big heatsink?
Maniac Posted February 3, 2009 Author Report Posted February 3, 2009 Nice layout and internals! Just one question? Why isn't the output 1/4 jack mounted inthe same blue PCB? Just curious. Can you share a bit more about the basic topology? It looks like opamp input stage followed by a discrete output stage? Mosfets under that big heatsink? Thanks for the compliments, The It is because we want to line up the center line of the jack and knob horizontally. Otherwise we'd have to lower the jack's position and make it look lopsided. The white wire you see connecting to the jack and RCA sockets are Belden silver plated copper wire with Teflon insulation. It's one of the better wires around that don't cost some crazy price. As for topology, it uses KECES Gen2 power supply that had been evolving for some time. It takes up the bottom part and left part of the baord in the internal photo. The part with the two blue pots is the precision voltage reference, and the left half of heatsink cools the two transistors controlled by the voltage reference. The whole power supply took up like 2/3 of the board space. The actual amp, uses National's LME49710 OP amp for voltage gain and LME49600 for current gain. It is a very simple circuit that is one hell of a devil to optimize, we had dozens of prototype board sitting there doing nothing because earlier designs didn't meet our requirements of performance. The black box you see near the pot is for gain control, which will make it a lot simpler for headphone users, as headphones comes in so many different sensitivity, and is very hard to pick a single gain setting that can suit them all. Anything else you would like to know?
Currawong Posted February 3, 2009 Report Posted February 3, 2009 Very nice clean and simple design. I understand entirely why you make them with a clear top. Very tempting to get one to try out one of your designs.
Maniac Posted February 3, 2009 Author Report Posted February 3, 2009 Very nice clean and simple design. I understand entirely why you make them with a clear top. Very tempting to get one to try out one of your designs. Thank you, we try to keep the top as clean as possible for both aesthetic and layout concerns, and some of the components are placed on the bottom for optinum layout and placement considerings. The side effect is the top sometimes gets a bit barren.
MASantos Posted February 3, 2009 Report Posted February 3, 2009 Thanks for the details! Looks like a really nice amp, both visually and spec wise! Thanks for the compliments, The It is because we want to line up the center line of the jack and knob horizontally. Otherwise we'd have to lower the jack's position and make it look lopsided. The white wire you see connecting to the jack and RCA sockets are Belden silver plated copper wire with Teflon insulation. It's one of the better wires around that don't cost some crazy price. As for topology, it uses KECES Gen2 power supply that had been evolving for some time. It takes up the bottom part and left part of the baord in the internal photo. The part with the two blue pots is the precision voltage reference, and the left half of heatsink cools the two transistors controlled by the voltage reference. The whole power supply took up like 2/3 of the board space. The actual amp, uses National's LME49710 OP amp for voltage gain and LME49600 for current gain. It is a very simple circuit that is one hell of a devil to optimize, we had dozens of prototype board sitting there doing nothing because earlier designs didn't meet our requirements of performance. The black box you see near the pot is for gain control, which will make it a lot simpler for headphone users, as headphones comes in so many different sensitivity, and is very hard to pick a single gain setting that can suit them all. Anything else you would like to know?
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