Right high % of info that matters in audio band is covered by 100$ devices and passive speaker units don't have any active life above their normal 2nd order roll off at HF so they covered as in case with Wesayso's world class performance but amps works up there and probably their roll off is also a more gentle 1st order, by the way what is output impedance supposed to be for PCA/SH/HyQu.
Maybe you should offer the builder the choice of lowering the bias if to suit his headphones. This way someone with very efficient headphone may tune down the bias for the batteries to last longer. As I see it the amp will consume virtually a constant amount of energy from the battery.
This is only a suggestion. BTW your PCB is very nice compact and well thought out.
PCA output impedance is calculated with LTSpice at 3ohm.
The calculated output impedance off the HyQu is 0.18ohms
I forgot what the SH is but it's got an IRFP9240 and IRFP240 CCS so probably about 0.3ohms.
Certainly. It's similar to the popular Ranchu/Aksa Quasi complimentary but since single rail doesn't need DC offset and has just bias trimpot. Bias can be set between 50mA to 130mA. It actually sounds quite nice at 70mA and 18v supply rail even for all but the crazy HE-6 headphones that require rediculous watts.
I am having some fun with the Coffee Money Headphone Amp. For anyone on a budget.
http://www.diyaudio.com/forums/chip-amps/310816-tda2030-coffee-money-headphone-amp.html#post5150348
http://www.diyaudio.com/forums/chip-amps/310816-tda2030-coffee-money-headphone-amp.html#post5150348
Another amp on a plank
Finally got around to mounting the HyQu on a board (spare piece of MDF from a speaker flat pack). It's nice to have a hard mounted input output jacks and a volume knob. Makes the amp semi transportable now. It might see use upstairs out of the lab finally.
Finally got around to mounting the HyQu on a board (spare piece of MDF from a speaker flat pack). It's nice to have a hard mounted input output jacks and a volume knob. Makes the amp semi transportable now. It might see use upstairs out of the lab finally.
Attachments
PCA Build Pictures!
Got my PCA up and running thanks to the suggestions of XRK back on page 101 (the DC boost converter and a LiPo cell). All I can say is that it sounds wonderful - it really helps add a much needed power punch to weak outputs without contributing any negatives or harshness to the sound. I'm using 0.47uF PPS input caps, and can't notice any degradation in the low frequencies - I may try the 4.7uF-10uF Silmic bypass at some point, but right now I'm enjoying the sound. The filters and output caps are all Panasonic FR: 2700uF/16V on the output and 1000uF/25V on the power supply paralleled with four 100nF C0G. All resistors are Panasonic ERA thin film, except the one 1ohm resistor off the boost converter which is an old favorite RN55.
The purple board is a custom battery charge/load sharing board copying the PMOS/Schottky design here: A Lithium Battery Charger with Load Sharing – Zak's Electronics Blog ~*
The only complaint I have with this configuration seems to be the inrush current from the boost converter makes the battery (and some USB supplies) go into protection. Once the circuit is started from a not-so-trigger-sensitive USB source, the USB cable can be unplugged and the system will work off the batteries until power is removed long enough for the capacitors to discharge (the LED dims to about half brightness and then it won't restart on batteries alone, but restarting before the capacitors fully discharge works fine). The boost converter has a low-power mode that it switches to which only draws a few uA when the switch is off, so I've left it permanently connected to the load sharing board. However it seems that coming out of that mode, or even coming from a fully unpowered state, it wants to charge the capacitors with as much current as it can pull (soft-start seems to be... not so soft). Unprotected lithium cells work fine as I originally tested it with an 18650 I had lying around while waiting for the slow boat from China.
I'd be super appreciative if anyone could come up with a solution that would allow the battery to properly start the circuit without, what I assume is happening, going into over-current protection. The ideas I have so far are an inductor in series between the load sharing and boost converter board, or a small NTC thermistor - which would waste power and potentially continue to when the unit is powered off.
Anyways, here's some pictures (the hot snot on the capacitors is now 3M double sided tape, don't worry )
Imgur: The most awesome images on the Internet
Got my PCA up and running thanks to the suggestions of XRK back on page 101 (the DC boost converter and a LiPo cell). All I can say is that it sounds wonderful - it really helps add a much needed power punch to weak outputs without contributing any negatives or harshness to the sound. I'm using 0.47uF PPS input caps, and can't notice any degradation in the low frequencies - I may try the 4.7uF-10uF Silmic bypass at some point, but right now I'm enjoying the sound. The filters and output caps are all Panasonic FR: 2700uF/16V on the output and 1000uF/25V on the power supply paralleled with four 100nF C0G. All resistors are Panasonic ERA thin film, except the one 1ohm resistor off the boost converter which is an old favorite RN55.
The purple board is a custom battery charge/load sharing board copying the PMOS/Schottky design here: A Lithium Battery Charger with Load Sharing – Zak's Electronics Blog ~*
The only complaint I have with this configuration seems to be the inrush current from the boost converter makes the battery (and some USB supplies) go into protection. Once the circuit is started from a not-so-trigger-sensitive USB source, the USB cable can be unplugged and the system will work off the batteries until power is removed long enough for the capacitors to discharge (the LED dims to about half brightness and then it won't restart on batteries alone, but restarting before the capacitors fully discharge works fine). The boost converter has a low-power mode that it switches to which only draws a few uA when the switch is off, so I've left it permanently connected to the load sharing board. However it seems that coming out of that mode, or even coming from a fully unpowered state, it wants to charge the capacitors with as much current as it can pull (soft-start seems to be... not so soft). Unprotected lithium cells work fine as I originally tested it with an 18650 I had lying around while waiting for the slow boat from China.
I'd be super appreciative if anyone could come up with a solution that would allow the battery to properly start the circuit without, what I assume is happening, going into over-current protection. The ideas I have so far are an inductor in series between the load sharing and boost converter board, or a small NTC thermistor - which would waste power and potentially continue to when the unit is powered off.
Anyways, here's some pictures (the hot snot on the capacitors is now 3M double sided tape, don't worry
)Imgur: The most awesome images on the Internet
Very nice work Raptorlightning!
I use a 0.47R 2W thin film panasonic resistor between the DC step up and the CRCRCRC filter and that seems to keep it from going to self protect. It burns some heat though so you lose some efficiency. Another option is a cap multiplier using a MOSFET that will have a slow ramp turn on and off function. It will suffer a 3 to 4v Vgs loss but then increase the DC step up. It is guaranteed to prevent self protect from in-rush. You can make one with a ZVN4306 actually.
Replace the upper right quadrant in this schematic (the IRFP240) block with a ZVN4306, a 100uF SMT for the 220uF, and a 2200uF 25v for the 4700uF, keep the rest the same. It will give about a 5 second ramp up if placed between the DC step up and the amp.
Juma's Easy-Peasy Capacitance Multiplier
I use a 0.47R 2W thin film panasonic resistor between the DC step up and the CRCRCRC filter and that seems to keep it from going to self protect. It burns some heat though so you lose some efficiency. Another option is a cap multiplier using a MOSFET that will have a slow ramp turn on and off function. It will suffer a 3 to 4v Vgs loss but then increase the DC step up. It is guaranteed to prevent self protect from in-rush. You can make one with a ZVN4306 actually.
Replace the upper right quadrant in this schematic (the IRFP240) block with a ZVN4306, a 100uF SMT for the 220uF, and a 2200uF 25v for the 4700uF, keep the rest the same. It will give about a 5 second ramp up if placed between the DC step up and the amp.
Juma's Easy-Peasy Capacitance Multiplier
Dude your soldering is some of the best I've seen!
Did you use paste?What series of PPS caps do you have on the input?
Dude your soldering is some of the best I've seen!
What series of PPS caps do you have on the input?
Thank you! No paste, just drowning levels of water soluble flux and Kester 44 63/37 with an ultrasonic bath + IPA and brush at the end. I'm a bit upset I pulled a pad on one of the electrolytics (oopsed it in backwards the first time), fortunately the rail was right next to it to connect it to. They're the Kemet SMR series, the ones I used specifically were Mouser # 80-SMR5474J50J0416.
xrk971 said:
I do have a 1 ohm resistor (the brown guy pictured) on the output of the boost converter before the capacitor bank on the board, no inter-capacitor resistance however (making a simple 1ohm/2000.4uF RC filter before the MOSFETs). I'd like to find a solution that doesn't involve a new board or many components to add, but the capacitance multiplier idea is something I've never seen in use before and quite interesting. 7 added components (using the 2000uF of electrolytics on the PCA itself for C15) doesn't seem too bad, but it means yet another little board in the box.
Any other ideas come to mind?
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Dude your soldering is some of the best I've seen!
What series of PPS caps do you have on the input?
Looks as clean as a stencil/paste reflow job! Look at the labels on R7, they are all aligned right side up instead of random like on my amps. Very clean.
The cap multiplier of done with SMT can be a very small board (1cmx1cm). I have made one once as part of the main SMT layout and it hardly took any extra room. About the simplest graceful ramp up and down plus provides ripple isolation if plugged into mains linear supply.
If anyone is in the DC area, there is a Head-Fi meeting in Gathersburg this Sat. I will bring Pocket Amps, Silicon Harmony, and HyQu for anyone interested in listening. Free but need to register in advance.
DC Area Head-Fi Meet and End-of-Summer SchiitStorm! - August 12, 2017 - Gaithersburg, Maryland! | Head-Fi.org
DC Area Head-Fi Meet and End-of-Summer SchiitStorm! Tickets, Sat, Aug 12, 2017 at 12:00 PM | Eventbrite
DC Area Head-Fi Meet and End-of-Summer SchiitStorm! - August 12, 2017 - Gaithersburg, Maryland! | Head-Fi.org
DC Area Head-Fi Meet and End-of-Summer SchiitStorm! Tickets, Sat, Aug 12, 2017 at 12:00 PM | Eventbrite
That was a lot of Schiit in one place
The Head-Fi organized SchiitStorm was a great event. Lots of very high end cool gear. I feel like more than 10 people brought their Focal Utopia headphones (circa $4k). So now I know what those sound like on the Silicon Harmony. Sublime. HiFiMan and Audeze were also there in force. I got to listen to a lot of SE Class A tube amps. Also heard some very nice DACs. A great environment to check out what stuff sounds like and everyone is so nice and easy going with you testing their multi thousand dollar headphones or amps.
Lots of feedback on my amps and by far, everyone agrees that Silicon Harmony is still king. Couple of guys also said that it sounds superb - along the best at this show and is better than a well regarded Class A amp that sells for $3500. I was really impressed by the sound that some of the $1000+ headphones sound like. And they all sound good on the SH, and the PCA was also very well received. The HyQu was also well liked but in the end, could not hold up to the SH when people used very resolving phones like the Sony MDR-1, Focal Utipia, Audeze LCD-2 and LCD-X. Another pleasant surprise was feedback that I got on the sound of the Focusrite 2i4 as a DAC: great sound, clear separation of instruments, nice soundstage, excellent detail. A good DAC that held its own against some really expensive DACs that were there.
Here are some photos of the event, which Schiit sponsored by providing the venue (a very nice clubhouse in a beautiful neighborhood in Gaithersburg, Maryland). I listened to several of the top Schiit tube amps and they sounded very nice. They ran very hot - the case felt about as hot as my SH (about 55 Celcius). I enjoyed all the amps. There was a young DIY'er there (sprigs) who had some impressive sounding P2P SE Class fleawatt tube amps. Overall it was some very good Schiit there.
A table full of Schiit:
A nice commercial tube amp (Zana Deaux):
Some cool DIY amps:
The XRKAudio table:
It was a nice way to spend a Saturday afternoon.
The Head-Fi organized SchiitStorm was a great event. Lots of very high end cool gear. I feel like more than 10 people brought their Focal Utopia headphones (circa $4k). So now I know what those sound like on the Silicon Harmony. Sublime. HiFiMan and Audeze were also there in force. I got to listen to a lot of SE Class A tube amps. Also heard some very nice DACs. A great environment to check out what stuff sounds like and everyone is so nice and easy going with you testing their multi thousand dollar headphones or amps.
Lots of feedback on my amps and by far, everyone agrees that Silicon Harmony is still king. Couple of guys also said that it sounds superb - along the best at this show and is better than a well regarded Class A amp that sells for $3500. I was really impressed by the sound that some of the $1000+ headphones sound like. And they all sound good on the SH, and the PCA was also very well received. The HyQu was also well liked but in the end, could not hold up to the SH when people used very resolving phones like the Sony MDR-1, Focal Utipia, Audeze LCD-2 and LCD-X. Another pleasant surprise was feedback that I got on the sound of the Focusrite 2i4 as a DAC: great sound, clear separation of instruments, nice soundstage, excellent detail. A good DAC that held its own against some really expensive DACs that were there.
Here are some photos of the event, which Schiit sponsored by providing the venue (a very nice clubhouse in a beautiful neighborhood in Gaithersburg, Maryland). I listened to several of the top Schiit tube amps and they sounded very nice. They ran very hot - the case felt about as hot as my SH (about 55 Celcius). I enjoyed all the amps. There was a young DIY'er there (sprigs) who had some impressive sounding P2P SE Class fleawatt tube amps. Overall it was some very good Schiit there.
A table full of Schiit:
A nice commercial tube amp (Zana Deaux):
Some cool DIY amps:
The XRKAudio table:
It was a nice way to spend a Saturday afternoon.
Attachments
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Hi Byrtt,
There was not an HP-1 there. It was an eye opener how much of the gear there used tubes.
Here was the $4k headphone - and it definitely sounds very very good. Very linear and neutral but the highs keep going and the attack is super crisp.
World's Best Headphone: The Focal Utopia | InnerFidelity
Hi Zman,
You are right, the meeting allowed me to share my gear and listen to some very high end stuff all in one place. You would never find this much high end gear in one place ever in any store. I have never heard tube headphone amps before - but have to say, headphones is a perfect fit because you only need 1w of Class A sound. They actually sound very similar to Silicon Harmony.
That Utopia by Focal looks and feels like a Ferrari or something exotic:
Carbon fiber frame, leather padding, beryllium diagphragm.
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Very well done X! Will there ever be an opportunity for working class guys like me to diy a SH? Then again - I cannot afford those Utopias anyway.
PS: I still love and enjoy my PCA! I'm not jealous...
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