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Post by jacobjhlee on May 4, 2015 15:56:25 GMT
Once you get it working I hope you love it as much as I do. Turns the HD650 from an excellent headphone to one that competes with the most expensive out there. IMHO. The project itself is enjoyable in it's own right  I'm not holding too much of an expectation but I am certainly curious! Going to withhold buying the next set of components until I get the board. With that considered I am hoping this project will be built within the next week. |
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solderdude
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Post by solderdude on May 4, 2015 17:04:06 GMT
Read the values, and both come up as 22V with a tolerance of a few decimals. Thanks! I'm now looking for a unloved piece of electronics I can re-purpose into a housing. Also, if anyone is looking to use this socket, bear in mind that the centre pin may need some widening before it makes good contact with the adapter tip. A small flathead screwdriver will do the trick. uk.farnell.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=15001&langId=44&urlRequestType=Base&partNumber=1216726&storeId=10151 A power supply that suddenly shows 1.3V when it's meant to show 22V is a rather confusing experience.
*Edit* Since an hour of this post, I forgot that I left this power supply running with the (now too hot to touch) resistors . Did another measurement: 22.8V before regulators 15V after regulators First time I've built something on a strip board that worked without needing anything re-soldered. You may have a 2.5mm centrepin plug on your power supply and used a 2.1mm centrepin socket. It does fit (not the other way around) but the contact isn't certain. 22-23V is excellent. The PCB is in the mail. Should arrive around the weekend, sometimes it takes longer. |
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Post by jacobjhlee on May 7, 2015 19:12:24 GMT
Board just arrived today!
Out of curiosity, what potentiometer value(s) would be ideal for this amp?
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Post by solderdude on May 7, 2015 19:35:40 GMT
I use 10k but 20k, 50k and even 100k can be used (as long as they are logarithmic) 10k or 20k is recommended. I have drawn the schematics for the HD600 SeNNator In there I used the designators as present on the PCB and the ones that need to go on 'non standard' positions. The latter are labelled differently. For the HD650
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Post by solderdude on May 7, 2015 19:46:22 GMT
A plot of the HD650 on the SeNNator and the HD600 (on its own SENNator)  |
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Post by jacobjhlee on May 7, 2015 21:26:09 GMT
As a final question. Would the wattage of the resistors matter in this? Would it be useful to have every resistor at 3W?
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Post by z3d on May 7, 2015 21:33:34 GMT
Nice Frans!
For the HD600 is this the final filter?
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Post by solderdude on May 7, 2015 21:34:53 GMT
the resistors are all 0.5W (SFR16 or SFR16S) type and 5%.
everything between 0.3W and 0.6W will be fine.
If you want you can use 2% or even 1% tolerance.
When you bend the legs of the resistors really tight (change of breakage) you can also fit SFR25 resistors in there.
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Post by solderdude on May 7, 2015 21:37:11 GMT
Nice Frans! For the HD600 is this the final filter? I suspect so. It is marginally different from the one the plots are shown. The final version has the 3-6kHz region reduced 0.5dB less. I still need to compare the HD650 and HD600 head-on but right now I a swamped. |
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Post by z3d on May 7, 2015 21:43:36 GMT
No problem Frans, take your time to enjoy the little giant-killers you created! The 0,5dB decrease is because you want to flatten a bit this frequency range (3-6khz) or the dips and peaks will remain the same with just a lower level of -0,5db? Also compared to hd650 filtered, this frequency range is already lowerered by around 1,5-2dB: do you feel HD600 have a way of presenting highs a little bit sharper than HD650, even if filtered and lowered? About doing A-B comparisons of different tubes (and of course with different gains) through Ember, it's possible (given a flat signal like 1khz in foobar) to match the volume just regulating the voltage detected with a voltmeter on the headphone female jack on the amplifier (L->gnd or R->gnd it's the same) ? Of course A-B comparisons between different headphones is not possible in this way cause of different impedances. |
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Post by solderdude on May 8, 2015 17:27:34 GMT
The 3-6kHz region is now lowered about - 1.5dB where in the version (where the plots were made) this was -2 dB. My HD650 is using the older pads. The 3-6khz boost is only present (in both HD600 and HD650, old and new driver) when the newer pads are used. So this has been addressed in the filters. The 'tutorial' on how to populate the filter circuit board so it becomes a SeNNator is now finshed. You can view/download it HERE: www.mediafire.com/view/b743m62ut9mdsb3/SeNNator_build_tips.pdf ( Large 4.6MB file so make take a while to load) |
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Post by z3d on May 10, 2015 13:05:54 GMT
Okay Frans, now I understand.
Thank you for the tutorial, I gave a quick read to it and I will make a list of the needed components for the HD600 filter; do you have already some codes from RS-online?
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Post by jacobjhlee on May 12, 2015 19:47:05 GMT
It seems like I unfortunately did something wrong in the process, and have ended up with a crackling HD650 as I plugged it in. No sound afterwards
HD650 is fine as it plays normally on my other dac/amp. So it may be poor wiring somewhere, or the wrong components being used.
I will take a break from all this DIY, and will continue to try debugging as the week progresses.
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Post by solderdude on May 12, 2015 20:28:43 GMT
It sounds like there might be DC on the headphone jack/out.
Check the pins on the op-amps.
All '1' and '7' pins must have close to 0V on it (a few mV)
All pin '3' and pin '5' must have 0V on it (no input signal).
Make sure you have the ground mod done correctly and the circuit is fed with + and - voltages.
All pin 8 must have the + voltage on it, all pin 4 must have the - voltage on it.
With the PCB off measure Ohms between the ground and pin 5 of IC101B (should be close to 0 Ohm)
With the PCB off measure Ohms between the ground and pin 3 of IC201A (should be close to 0 Ohm)
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Post by jacobjhlee on May 12, 2015 21:10:42 GMT
Pin 1 (IC101A) : 0.82 V
Pin 3 (IC101A) : 0.87 V
Pin 5 (IC101B) : 0V
Pin 7 (IC101B) : 14.2 V...
Pin 1 (IC201A) : 14.2 V
Pin 3 (IC201A) ; 0V
Pin 5 (IC201B) : 0.87 V
Pin 7 (IC201B) : 0.82 V
Pin 5 (IC101B) : 0.9 Ohms (Touching probes together gives me 0.9 - 1 Ohm so I guess this is near 0)
Pin 3 (IC201A) : 0.9 Ohms
The reason why this happened was because I overlooked a detail when soldering the jumper wires for Power Option 1 Instead of wiring from Pin 2 to Pin 3 on IC3. I wired Pin 1 to Pin 3, which may have caused most of the aforementioned. Now after so much DIY I think I have found the best way to relax from all this  ! |
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I'm not holding too much of an expectation but I am certainly curious!
!