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bitzie - questions

Printed From: Graham Slee Hifi System Components
Category: Headphone Audio
Forum Name: Portable Headphone User
Forum Description: Technical Q&A, hints and tips
URL: https://www.hifisystemcomponents.com/forum/forum_posts.asp?TID=5257
Printed Date: 29 Mar 2024 at 4:41am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com


Topic: bitzie - questions
Posted By: magical_mouse
Subject: bitzie - questions
Date Posted: 06 Aug 2021 at 8:11am
hi i have a bitzie on trial (through the try before buying scheme) and am generally impressed but have some questions if anyone can answer them i would appreciate it.

1. the power output is not huge, i can see the problem of trying to work with a range of headphones which is why i guess some manufacturers have gain settings - i had a problem with my oppo pm3 - the volume has to be at almost maximum to get enough volume which does not leave much headroom

2 is there any way to alter the gain - i used to have (years ago) a unit that allowed jumpers to be moved to provide different gain settings

3 the alternative is to increase pre-amp output by several db within my musicbee but i am unhappy to do this as it may introduce distortion and is not bit perfect.

4 vey impresses with usb latius power cable - it can be usd with mains/usb powerpack battery/second usb output on laptop all of which seem superior to normal usb cable

d


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magical_mouse



Replies:
Posted By: Graham Slee
Date Posted: 06 Aug 2021 at 9:14am
The problem in getting high volume with some headphones is due to the power supply limitation - it runs on the USB bus 5 volts.

It could be argued that the power wire could be designed to allow a higher supply voltage, but the connection used is the same as the USB bus and could inadvertently result in permanent damage.

We also have to ensure we don't exceed the USB standard power unit when bus-powered. Other products have caused computers to hang or blue screen by exceeding it.

Increasing gain would therefore lead to rail clipping - bad for headphone voice coils and diaphragms.

The Bitzie's other uses are providing a preamp line-level output via the adapter, which can connect to another (perhaps more powerful) headphone amp, as a USB preamp to drive a stereo power amp, or to output S/PDIF to a "non-USB DAC" input. Therefore, the Bitzie is more than a dedicated headphone amp. The output stage had to be made "clean" for other line-out uses.

With so many drivers falling foul of Windows 10 updates (and who knows what 11 will be like), I think the driverless connectivity of the Bitzie is its main SP.

However, given a more compatible headphone (and there are plenty), the loudness can be pretty sufficient. As with all our volume control equipped products, it is designed to go to the full rotation without the resulting distortion of some high gain products.



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That none should be able to buy or sell without a smartphone and the knowledge in how to use apps


Posted By: Graham Slee
Date Posted: 06 Aug 2021 at 9:39am
The other thing I always forget to mention is the analogue filter (which is combined in the output stage), and its endearing function of making digital fatigue go away!

Sorry if this is getting to sound like promotional material Wink

(and all achieved using full size components - chips excepted - and hand built in such a small case) WinkWink


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That none should be able to buy or sell without a smartphone and the knowledge in how to use apps


Posted By: magical_mouse
Date Posted: 06 Aug 2021 at 11:01am
Thank you for that explanation, i understand the reasoning and the last paragraph is helpful

'As with all our volume control equipped products, it is designed to go to the full rotation without the resulting distortion of some high gain products'

This makes a considerable difference as the amplifier is loud enough although close to maximum which i previously thought would introduce distortion and lack of headroom for loud passages.

I was running this off 5v 2.1A battery pack - should i be using the 5v 1A socket instead?

BTW amazing & quick help - thank you

d


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magical_mouse


Posted By: Graham Slee
Date Posted: 06 Aug 2021 at 7:48pm
Originally posted by magical_mouse magical_mouse wrote:


I was running this off 5v 2.1A battery pack - should i be using the 5v 1A socket instead?


Either will be OK. It will only draw the current it needs, which is about 100mA.

Battery internal impedance is quite complex at audio frequencies (and RF), and the cap load in the Bitzie isn't very big because of the limits on the USB bus. In the old days it was usual to parallel a 1,000uF electrolytic with a battery. A mains derived regulated power supply with a good smoother cap might sound better.


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That none should be able to buy or sell without a smartphone and the knowledge in how to use apps


Posted By: magical_mouse
Date Posted: 07 Aug 2021 at 9:57am
Thank you, if i plug it into the mains using a usb charger - is this the same as a mains derived power supply?

david


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magical_mouse


Posted By: Graham Slee
Date Posted: 07 Aug 2021 at 12:24pm
If it says 5V on it, yes.

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That none should be able to buy or sell without a smartphone and the knowledge in how to use apps



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