CHANGSTAR: Audiophile Headphone Reviews and Early 90s Style BBS
Lobby => DIY => Topic started by: Valentin Hogea on March 17, 2013, 05:37:49 PM
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Will update with all the stuff I gather during this trip...
Why create an empty thread? Well... I know how frustrated I was not to find a place with all the "data" gathered. Design tips. Vendors. PCBs. Bill-of-material. Etc. Etc.
If I create this thread... I have to write something. Let's call it motivation..
/V
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And if anyone is wondering why build the DYnamite/Dynapsu when I'm more than content with my ZDSE. Three reasons.
(1) I have to orthodynamic headphones that do not share the HD800's love for the ZDSE.
(2) It resembles the KGSSHV "much" from my n00b-ish POV. Both the case/cooling needed and the boards/parts to some extent.
(3) The rails are +30V/-30V. The KGSSHV will have +500V/-500V rails and 580V bias. I cherish my life. 500+ volts kills.
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I think it's a good idea. You'll have a great SS amp and a great tube amp. :)p6
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My first DIY amp was a Dynalo+Sigma22+Jtree attenuator. If by Dynamite you mean a balanced Dynalo, then ask away- I'll try to answer everything. To be honest it's a very challenging first build with some potential issues poorly documented.
P.S. Never underestimate electricity. 30VAC is able to kill you if you happen to puncture your skin with loose wire strands. It's the current that kills. A current between 100-200mA is a killer, and all that it needs is a low impedance entry point into your system. Luckily for you impedance for dry and undamaged skin is 100000-400000Ohms which means relatively high voltages are needed to pump the killing current. Keep in mind that moist or damaged skin can have impedance below 300Ohms. You do the math.
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Dynamite is a balanced dynahi
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New revised Dynahi is coming soon with onboard heatsink (easier and cheaper to build), different output transistors, less powerful to still far more enough to drive the HE6 or K1000.
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Ah, the Dynahi... Well, it isn't that different to the Dynalo circuit wise.
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My first DIY amp was a Dynalo+Sigma22+Jtree attenuator. If by Dynamite you mean a balanced Dynalo, then ask away- I'll try to answer everything. To be honest it's a very challenging first build with some potential issues poorly documented.
P.S. Never underestimate electricity. 30VAC is able to kill you if you happen to puncture your skin with loose wire strands. It's the current that kills. A current between 100-200mA is a killer, and all that it needs is a low impedance entry point into your system. Luckily for you impedance for dry and undamaged skin is 100000-400000Ohms which means relatively high voltages are needed to pump the killing current. Keep in mind that moist or damaged skin can have impedance below 300Ohms. You do the math.
Yeah... It's the current that kills. True that.
Survived a couple of 230V-adventures. Not even arrythmia after.
But, my point was. I want to try my wings with the Dynamite before I start playing with the KGSSHV.
And I will be taking som pretty radical precautions. Double sugical gloves [if we can use diathermia during operationswith them, then they isolate pretty well ;)] and rubber sneakers always as soon as the current is on and/or I suspect that caps can harbor nasty electrons in them.
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Well, there isn't much need for gloves or rubber boots... Just keep in mind to never rush or solder when tired.
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A mock-up with some poor photoshop-touches, just to get a feel.
Yeah, I know the 4-pin XLR looks weird. Don't take it too serious. ;)
(http://i50.tinypic.com/msd3sg.jpg)
I've read some stuff about the solders on the KGSSHV being a bit more dificult. 500V arcs easier than 30V.
So... I will take some extra precautions with that one. No rubber stuff with the Dynamite.
/V
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2 power switches?
Also, when you put the text above the volume, it might be hard to see it when looking at a specific angle. Also, it will make the center a bit too 'busy'. Bringing the text to the opposite side of the jacks will make the panel more balanced. Just take a look at what Justin did with his GS-X2 or BHSE.
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Not 100% identical but with the same feel. I think I'm pretty satisfied.(http://i49.tinypic.com/k2ifrb.jpg)
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Some more designing...
Waiting from Lil' Knight's boards. Until then... I can always dream away to the finished build with some chassi work.
(http://i46.tinypic.com/vzvpc2.jpg)
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Too busy front panel. At least for my taste.
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I'm thinking of putting the speaker terminals in the back, however, the idea with putting them in the front was to avoid unecessary switches (i.e. headphone/speakers), but maybe... better to have a lever with 1 = 4-pin XLR / 2 = 2x3pin XLR / 3 = speakers...
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If you use those combination 3-pin XLR/1/4" headphone connector jacks (see new GS-X) you won't need separate 1/4" jacks.
Though personally if it's an amp for my own use I would do away with all of those and only have a 4-pin XLR connector... dual 3-pin XLR is archaic :)
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If you use those combination 3-pin XLR/1/4" headphone connector jacks (see new GS-X) you won't need separate 1/4" jacks.
Though personally if it's an amp for my own use I would do away with all of those and only have a 4-pin XLR connector... dual 3-pin XLR is archaic :)
Hi mate!
I might as well install the Neutrik 2x3's too. Who know's. Better safe than (using a butt-ugly converter).
Those aren't 1/4" TRS jacks, but Speaker Terminals. The idea with having everything in front is Thus avoiding to forget e.g. speakers plugged in (in the back) when powering up and thus avoiding delay relay's and such. But maybe RudeWolf is right. Too busy in the front?
I'll have to give it some more thought. Anyways... At least a couple of weeks before it's time to order the enclosure, so no hurry.
/V
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Btw- are you thinking of using the Dynahi as a pre-amp?
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Nope, as an integrated amp. The back will only have loop-outs, no pre-outs.
I want to have the possibility to drive high.efficiency speakers in the future (especially since I sold of all my speaker gear).
Since I'm going for a pretty hefty enclosure with chunky heatsinks, it should hold for about 10-15 W into a 8 Ohm load...
/V
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Scratch the above... A Dual-Ch Dynahi gives 18-19 Wrms before clipping. As such a Quad-Ch Dynamight should at least generate about 25, especially with dual PSU-boards and such. .... I think. ;)
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The output devices on the Dynahi aren't that happy with driving speaker loads. The Beta22 mosfet output stage might suit you better but really none of these amps are that well suited for speakers. If you want a simple speaker amp you could whip up a Pass F-something.
Check out DIYA for nice speaker amp designs. I too have a speaker amp in my battleplan for this year.
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I'm building it to use as a headphone amp, but since it's so easy to add speaker terminals, I'm more like "Why not?".
Not looking to drive any inefficient monsters, more like something in the 95-100 dB/W-range. Eventually...
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Boards = 70% fully stuffed.
Damn it's like 300 times easier soldering these boards than O2..
Have no idea how 6 x 470 uF 35 V turned into 3 x 470 uF 63 V... And some other weird stuff. The BOM I used must have been very inaccurate versus the new boards...
or ... I must lay off smoking crack.
Waiting for some SAND to come in from the US...
Pics soon.
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Progress...
(http://i35.tinypic.com/2wgch1h.jpg)
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Looking good Val. Still missing a few parts?
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Thx Chris!
Yeah... Inevitably... No matter how hard I tried to follow the BOM I forgot some:
Electrolytics 3 big and 3 small on the DynaPSU x 2
2 different bridge rectifiers on the DynaPSU x 2
All the heatsinked-SAND on the DynaHi x 2 (awaiting a bdent order currently residing at fellow american for reshipping)
4 x 10 kOhm trim pots x 2 on the DynaHi x 2
Film cap (WIMA) on the DynaHi x 2
And I need to figure out what 20 KLO and KDT are... Dual Tracking? I thought they were resistors and stuffed wrong...
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KGSSHV is almost complete.
Amp boards: Awaiting some heatsinked and non-heatsinked SAND from bdent (for reshipping)
PSU: Missing two resistors 15k and 747k (or something like that) one of each per PSU
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And some OP-amp sockets, LM1021 x 4
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In other words. Either the boards got updated after I ordered or I'm losing my mind.
(Can't chat later, at work until 22:00)
Cheers,
V
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your choice of local feedback for each power supply or dual tracking. use one or the
other, not both. at this point, I don't remember which set of parts go with which.
too many designs, so little time.
in purgatory till may 17. but probably till june 6.
I hate black tie an tux events.
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your choice of local feedback for each power supply or dual tracking. use one or the
other, not both. at this point, I don't remember which set of parts go with which.
too many designs, so little time.
in purgatory till may 17. but probably till june 6.
I hate black tie an tux events.
Hi Kevin!
Thx for your reply. Would you mind explaining the above. I'm not that experienced (yet) regarding feedback circuits and similar stuff.
Would it be a trim-pot that should be used in those places. And only choose one of the two?
Last but not least. What would you think about stacking the boards above each other with long 5.5 mm screws in a 5U-case?