I have managed to assemble PSUv2 and BAL-BAL without any issue at all.
I tried with Balance out from A&K 100mkII and AKG 601. Sound is good and very detailed with good low end but the gain is somehow too small for a headphone system.
My suspect is either the impendance of AKG 601 too high (120 Ohm) or the A&K output signal is not high enough (2V according to,specs). Or something is wrong with the circuit which I doubt it.
Anybody has encountered similar behaiour like this?
I tried with Balance out from A&K 100mkII and AKG 601. Sound is good and very detailed with good low end but the gain is somehow too small for a headphone system.
My suspect is either the impendance of AKG 601 too high (120 Ohm) or the A&K output signal is not high enough (2V according to,specs). Or something is wrong with the circuit which I doubt it.
Anybody has encountered similar behaiour like this?
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Comparing simple resonance, with parallel-cap PI behavior
tankcircuitnoise: I view the VDD network to also be a design issue.
This PNG has two circuits.
Top is series RLC, L being the wiring from Supply to circuit, C being the local charge storage; note there is ONLY ONE interesting point in the frequency response: the peaking of the resonance.
Bottom is 2 caps in parallel, one 1,000uF and other 1uF, with 1meter wire (1uH) between. The first 3 plots show peak at 15.9KHz (1uF & 1uH, ignoring the 1,000uF); varying the ESRs does not move the peak, tho the height does drop.
In the 4rth plot, I add a second 1uF in parallel with first, and we get a new peak. We need a lot more damping Resistor than 10milliOhms.
Use the formula R_zeta1 = 2*sqrt(L/C) to compute the critical-dampen R value.[/QUOTE]
tankcircuitnoise: I view the VDD network to also be a design issue.
This PNG has two circuits.
Top is series RLC, L being the wiring from Supply to circuit, C being the local charge storage; note there is ONLY ONE interesting point in the frequency response: the peaking of the resonance.
Bottom is 2 caps in parallel, one 1,000uF and other 1uF, with 1meter wire (1uH) between. The first 3 plots show peak at 15.9KHz (1uF & 1uH, ignoring the 1,000uF); varying the ESRs does not move the peak, tho the height does drop.
In the 4rth plot, I add a second 1uF in parallel with first, and we get a new peak. We need a lot more damping Resistor than 10milliOhms.
Use the formula R_zeta1 = 2*sqrt(L/C) to compute the critical-dampen R value.[/QUOTE]
Attachments
Hi, apologies if these question have been asked a lot before. I'm new to diy
Where can i find research materials for learning everything related to putting together 'the wire'. I'm specifically interested in power supplies, grounding and implementing a pot or stepped attenuator. Also if it's possible to convert to battery power, say 3.7v 3400mah li ions
Most of the wiki pages on this forum don't work anymore
The BOM doesn't include connectors or recommended wire gauge/brand? For Aussie, which stores do you buy the BOM components from.
Where can i find research materials for learning everything related to putting together 'the wire'. I'm specifically interested in power supplies, grounding and implementing a pot or stepped attenuator. Also if it's possible to convert to battery power, say 3.7v 3400mah li ions
Most of the wiki pages on this forum don't work anymore
The BOM doesn't include connectors or recommended wire gauge/brand? For Aussie, which stores do you buy the BOM components from.
Is there a direct competitor for THE wire or is this best amp kit there is? Just looking at something to power my DT990's. how about Low distortion ultra-fi headphone amplifier stereo RSA XP-7 assembled ! | eBay
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The closest circuitry I listened is the FIIO E12, and it sound really good to my ears.
As far as through hole vs. SMD, the wire PCB is pretty easy SMD to deal with (no super small footprint components).
If you have to SMD experience, you can buy practice kits on eBay for few bucks, watch a few videos, and you will be expert in no time.
Just remember, for SMD, good flux and solder is the key.
As far as through hole vs. SMD, the wire PCB is pretty easy SMD to deal with (no super small footprint components).
If you have to SMD experience, you can buy practice kits on eBay for few bucks, watch a few videos, and you will be expert in no time.
Just remember, for SMD, good flux and solder is the key.
SMD is chosen because of components availability (as relatively cheap 0.1% resistors) and shortest possible signal paths. Like decoupling capacitors directly at IC supply pins. Point to point probably would be performing worse and may introduce stability issues. You may check this thread discussing usage of PCB vs. P2P - http://www.diyaudio.com/forums/chip-amps/252436-lm3886-pcb-vs-point-point-data.html
Finally I put BAL-BAL in a nice casing:
https://flic.kr/p/NRpDAu
The more I listened, the more I like the sound. It's different compared to my tube amp. It seems the problem lies on the headphone I use (AKG601). It sounds thin and lacking details compared to top-line model from Sennheisser.
https://flic.kr/p/NRpDAu
The more I listened, the more I like the sound. It's different compared to my tube amp. It seems the problem lies on the headphone I use (AKG601). It sounds thin and lacking details compared to top-line model from Sennheisser.
Agree.
It's a no nonsese circuitry based on Texas Instrument proven design. That's all. What can you expect? We don't need esoteric stuff here, but sound.
It's a no nonsese circuitry based on Texas Instrument proven design. That's all. What can you expect? We don't need esoteric stuff here, but sound.
Strange place to ask for an opinion to say the least.
Of course The Wire is the best, as long as you are asking in the thread.
There are a million kits outside, but they will have a hard time competing at this price point AND size.
Thanks!
I don't quite get the buffer part, but I should maybe look into that more somewhere else, I'm new to amp building.
Buffer why?
A vol pot has a maximum output impedance of roughly one quarter of the pot value.
Thus a 100k vol pot has a max Zo ~ 25kohms.
That 25k cannot drive any decent length of cable, maybe 10" worth.
Reduce the vol pot to 50K and it will be able to drive twice as much cable capacitance.
Reduce it to a 10k pot and you can drive ten times as much cable capacitance.
To avoid these cable and cable capacitance issues, you can add a stage that can drive the cables. An amplifier that does this without any extra gain is a Buffer.
It conditions the vol pot output so that it can drive all sensible cable lengths.
A vol pot has a maximum output impedance of roughly one quarter of the pot value.
Thus a 100k vol pot has a max Zo ~ 25kohms.
That 25k cannot drive any decent length of cable, maybe 10" worth.
Reduce the vol pot to 50K and it will be able to drive twice as much cable capacitance.
Reduce it to a 10k pot and you can drive ten times as much cable capacitance.
To avoid these cable and cable capacitance issues, you can add a stage that can drive the cables. An amplifier that does this without any extra gain is a Buffer.
It conditions the vol pot output so that it can drive all sensible cable lengths.
Hi there, folk,
a friend of mine would be kind enough to give me one of his BAL-BAL modules. For now, I'm planning to use SE inputs, later I want to use a balanced DAC instead. This generous friend mentioned above told me, that when using SE inputs he measured a DC offset at the outputs of up to 100mV(!). Is this a normal behavior of this circuit? I mean, such high DC offsets could harm most of the earphones available...
Best,
Dominik
a friend of mine would be kind enough to give me one of his BAL-BAL modules. For now, I'm planning to use SE inputs, later I want to use a balanced DAC instead. This generous friend mentioned above told me, that when using SE inputs he measured a DC offset at the outputs of up to 100mV(!). Is this a normal behavior of this circuit? I mean, such high DC offsets could harm most of the earphones available...
Best,
Dominik
The BAL-BAL may be set up for a DC coupled input.
If you have a balanced impedance input then both the Cold (-IN) and Hot (+IN) see exactly the same source impedances.
When you convert to unbalanced, the impedances seen at the two inputs end up being different. This difference in source impedance gives an input offset voltage and that gets translated into an output offset.
You have two choices:
a.) connect the Cold (-IN) input via a matching resistance to the Audio Ground (Signal Return)
b.) convert the two inputs to AC coupled so that the source DC resistances are never seen by the Hot and Cold inputs.
If you have a balanced impedance input then both the Cold (-IN) and Hot (+IN) see exactly the same source impedances.
When you convert to unbalanced, the impedances seen at the two inputs end up being different. This difference in source impedance gives an input offset voltage and that gets translated into an output offset.
You have two choices:
a.) connect the Cold (-IN) input via a matching resistance to the Audio Ground (Signal Return)
b.) convert the two inputs to AC coupled so that the source DC resistances are never seen by the Hot and Cold inputs.
Hi Guys,
Andrew is spot on (as usual) is his reply. If you are planning to run the BAL-BAL with SE input, then it would be prudent to implement option A or B as AndrewT listed.
Also, as a heads up, I have a few days off this week, so I will be sending out payment requests and shipping orders for anything currently left on the spreadsheet over the next few days.
Once those orders are filled, I will likely transition the remaining stock to Tim (Bimmer100) who will take on order fulfillment directly from his store. I don't have all the details in place just yet, but we will get it sorted out over the next few days.
This should provide a more consistent supply of boards, and faster shipping / response times than I can currently provide.
Happy holidays to everyone!
Regards,
Owen
Andrew is spot on (as usual) is his reply. If you are planning to run the BAL-BAL with SE input, then it would be prudent to implement option A or B as AndrewT listed.
Also, as a heads up, I have a few days off this week, so I will be sending out payment requests and shipping orders for anything currently left on the spreadsheet over the next few days.
Once those orders are filled, I will likely transition the remaining stock to Tim (Bimmer100) who will take on order fulfillment directly from his store. I don't have all the details in place just yet, but we will get it sorted out over the next few days.
This should provide a more consistent supply of boards, and faster shipping / response times than I can currently provide.
Happy holidays to everyone!
Regards,
Owen