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C&C BH Portable Headphone Amp (80 Hours from a Single Charge!) [Buyer Review] - Page 185

post #2761 of 3310

Hey. It's me again. Does anybody have a pair of Sennheiser IE8 to try with the BH? I have some interesting findings concerning the Out1 vs Out2 which I would like someone else to chime in on. So please try both outputs and report what you hear! You're in for a surprise (well, that depends on what you're expecting)...

post #2762 of 3310
Quote:
Originally Posted by docentore View Post

I still haven't found the rest of capacitors available to buy in normal prices, so I decided to use what I have, at least to change one pair - 0.22uF. I've used Vishay/BC 0.15uF + Wima 0.068uF in parallel, giving me 230nF - close enough. They did fit but it is really tight fit.

 

Overall performance has improved after those few swaps so far but to make sure I'm going to compare fully modded amp with unmodded if I can find around here.

 

I have measured voltage with fully charged battery and compared it with voltage while connected to USB port. The difference was around 5mV. Also have compared sound with fully charged battery and USB connected to amp on its own - I can't hear the difference. I would say the better bass response is to do with battery discharging (mind that Li-Ion battery swings from fully charged to discharged from 4.2V to little bit less than 3.7V) which is 0.5V and this might cause difference in sound.

 

As for higher voltage mods etc, The 5V voltage step-up pcb would not fit inside, there is no space. I would suggest if one is brave enough to:

1. Take out battery completely.

2. Solder usb input directly to battery terminals bypassing charging circuit.

3. Connect portable power bank to miniUSB port.

This would give real and constant 5V, but I'm not bothered with doing so, I'll stick with component swap and tweaking as I think there is more potential there.

 

More to come when I will get rest of the parts!

 

Hey Docentore. 

Nice mods!

Did you only recap or modded something else.

I just received mine, gonna recap it as well =D

post #2763 of 3310

Thanks.

Just recapped for the moment, but only the 0.015uF, 0.15uF and 0.22uF Film caps. I swapped electrolitycs to: 2x Nippon chemicon KZJ and Panasonic FR as well

I also wanted to swap tantalum caps, as I didn't like the way they look (dark, like burned) for oxicaps but the ones I bought didn't fit. So I took some 100uF caps from scrapped Macbook Pro logic boards (at least I know they are genuine and looking ok) and solldered them in place of yellow tants.

 

What I'm planning to do is:

1. Swap the pot for alps 097, I have some other pots, but I can't find nice knobs to fit.

2. Because I'm having trouble with finding good quality film caps with values of 0.12uf and 0.18uf I'm thinking of swapping them for 0.1uf (instead of 0.12uf) + 0.15uf (instead of 0.18uf) and 0.47uf (instead of 0.22uf) and see if it will affect the sound in plus.

 

But overall I'm happy with the mods so far.


Edited by docentore - 8/22/13 at 9:35am
post #2764 of 3310

Great.

Im Gonna mod mine as well. Really liked this tinny amp.

The only think I need right now is get the board out the case. Lol! biggrin.gif

Any tips on how to do that?

post #2765 of 3310

I did it this way:

1. Unscrew all 4 screws,

2. Take off volume pot knob and bothe panels

3. Pulled the board by pulling gently(!) the volume knob and pushing the board from the other side using some hard plastic tool.

 

Just take your time, you might have to move the pcb few times while still in the case to loose it abit.

post #2766 of 3310

does that battery seem completely proprietary or do you see a way to replace it?

  Mine seems toasted it won't go beyond maybe a few hours before it dies out. Figured since you were in there tinkering maybe you thought about that also. At this point I really don't mind ruining it if there's a possibility.  Or just go for an XO2...


Edited by nick n - 8/22/13 at 6:17pm
post #2767 of 3310

There seems to be a bit of mystery over what USB power do to BH, and whether a 5V step up will really help to unleash the power within the amp. So I did a bit more research into it by carrying out some measurement on the circuit. Here are the finding: BH has a +/- 4V power supply line, generated from the Li-ion battery. It doesn't seem to vary a lot whether it is on battery or USB power.

 

So if voltage doesn't vary by much on power supply, what does? Well, the current does. With the same output volume (*= voltage), the current output (to my usual 47ohm dummy load) jumps from around 169mA to 250mA with the USB power connected, making it close to a whopping 50% increase in total power. That's what contributes to the SQ improvement I detected previously.

 

So what does that tell us? Well, the 5V step-up might not be necessary - but it is not useless either. Many step-up circuit also boosts current as well, and that's the key to why using an external power bank with BH can also boost its performance (*given that power bank are also using 4.2V Li-ion inside, but with a 5V boosting circuit). So the key is really to increase the current supply to the amp, voltage is less important.


Edited by ClieOS - 8/22/13 at 9:09pm
post #2768 of 3310
Quote:
Originally Posted by ClieOS View Post

There seems to be a bit of mystery over what USB power do to BH, and whether a 5V step up will really help to unleash the power within the amp. So I did a bit more research into it by carrying out some measurement on the circuit. Here are the finding: BH has a +/- 4V power supply line, generated from the Li-ion battery. It doesn't seem to vary a lot whether it is on battery or USB power.

 

So if voltage doesn't vary by much on power supply, what does? Well, the current does. With the same output volume (*= voltage), the current output (to my usual 47ohm dummy load) jumps from around 169mA to 250mA with the USB power connected, making it close to a whopping 50% increase in total power. That's what contributes to the SQ improvement I detected previously.

 

So what does that tell us? Well, the 5V step-up might not be necessary - but it is not useless either. Many step-up circuit also boosts current as well, and that's the key to why using an external power bank with BH can also boost its performance (*given that power bank are also using 4.2V Li-ion inside, but with a 5V boosting circuit). So the key is really to increase the current supply to the amp, voltage is less important.

Thanks ClieOS for clarifying, that was my suspection, but I could not confirm without proper tools (don't have the dummy load circuit and my Fluke mm is on its last legs). Now back to the drawing board to find a easiest and safest way to increase current

 

Quote:
Originally Posted by nick n View Post

does that battery seem completely proprietary or do you see a way to replace it?

  Mine seems toasted it won't go beyond maybe a few hours before it dies out. Figured since you were in there tinkering maybe you thought about that also. At this point I really don't mind ruining it if there's a possibility.  Or just go for an XO2...

I'm going to spent some time experimenting with film caps over weekend so I'll check the battery out. I could not see the middle pin connected anywhere, but I did not test it properly. I have few li-ion mobile phone batteries so I'll check if any of them can be charged, but I would say you are ok with any battery that will fit inside. Just make sure that you connect polarity the right way.

EDIT: looks like the battery is compatible with Nokia 5M battery


Edited by docentore - 8/23/13 at 4:54am
post #2769 of 3310
I am going to order in a couple of days but was wondering if there's any uk or eu owners that are looking sell send me a PM.
post #2770 of 3310
BH hype train moves very well, yupi hey :-D
post #2771 of 3310

Got my C&C BH in March. Use it pretty consistently. Just had to charge it for the first time last night. When I realized it was dead I was dumbfounded. Guess somewhere in my head I decided it was never going to need charging.biggrin.gif

post #2772 of 3310

Since cables come up a lot in this thread I want to ask you guys a question. Based on my reading of this thread over the past 2 days I'm assuming silver plated copper and the silve-copper wires aren't the same. Correct?  If thats true then could you please tell me what sound sig each of them have?  I know pure silver is for treble and detail, and pure copper Is for warmth and bass, but the other 2 I'm not sure about.

post #2773 of 3310
Quote:
Originally Posted by Vidmaven View Post

Got my C&C BH in March. Use it pretty consistently. Just had to charge it for the first time last night. When I realized it was dead I was dumbfounded. Guess somewhere in my head I decided it was never going to need charging.biggrin.gif

 

Lol! Yes, the first time the BH dies is a bit of a shock, isn't it!

 

Btw, how does the C3/BH combo compare to the X3 as far as you are concerned?

post #2774 of 3310

popcorn.gif

post #2775 of 3310

Does any one else experience crackling/static problems when the unit is plugged in to charge? Not load enough to be overly noticable suring operation, but when there is no input signal I get quite a lot.

 

EDIT: It only gets really bad if i have my DAC attached but with no signal generated, so it could be some coupling issue. But it only happens badly when plugged in. There is a little without, but a hell of a lot more when plugged in. I expect some static on the input with no signal coming through, but it's wierd that charging the device makes it so much worse.


Edited by yblad - 8/25/13 at 5:53am
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