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Post by albroun on Oct 14, 2011 14:31:52 GMT
I am looking for a headphone amp with some means of restricting the maximum volume and / or overload protection.
It would be for use with a hifi system - at present my amplifier is far too powerful for the headphones I have - Sennheiser HD555 and 380Pro, and I have to keep the volume only just above zero! Portability for use with an iPod on the go would be useful too, but mainly it is for use with my main amp.
At present I have an iPod Classic (through a Cambridge Audio dock), and also a Cambridge Audio CD player. They both go through a pretty old 1980's Technics amp - nothing special but the sound quality is much better than listening through the iPod directly.
I have tried the well-known B-Tech headphone amp but this did not have a good overall tonal balance - too much bass in relation to treble. Also the maximum volume was too high, and no means of limiting it other than making sure the volume control was kept down. Dont know if it has any overload protection.
I have also tried a portable headphone amp - the Fii0 E7 (through their L3 dock cable). This does have a volume limiting system and using the L3 dock cable with its standardised output enables good volume limitation (with my headphones anyway), but I could not detect any significant improvement in sound quality over simply using the normal iPod headphone socket. It was certainly inferior to using my full-size amp.
Any help appreciated.
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xerxes
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Post by xerxes on Oct 14, 2011 15:35:19 GMT
There are a couple of things you could do make the headphone output quieter, so that you can use more of the volume controlls range. 1. Attenuate the input to the headphone amp. You could do this with a couple of resistors on the back of the input sockets, or if there's room, build them into the phono/RCA plugs of the cable used with your headphone amp. See here: www.uneeda-audio.com/pads/2. Increase the resistance to the headphones. There are probably a couple of resistors in the output to the headphone jacks left and right channel, you could increase the value of these, or put them in the headphone jack, if it's not a moulded one and if there's room. I did something similar, by making up a short extension/adapter cable for use with a pair of low impedance headphones, so I had a 3.5mm socket and a 6.5mm jack plug with a couple of 160ohm resistors in it that allowed me to use more of the volume control range. I think you could also look at adjusting the amplifiers gain, but you'd have to understand the amp's circuit and know what resisters to change and that's a bit beyond me.
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Post by albroun on Oct 14, 2011 20:36:54 GMT
Hi Xerxes - many thanks for the reply. Unfortunately I am technically electronically clueless, though I am sure your reply will be useful to many other forum users who might have a similar issue.
Basically I need to purchase a new headphone amp or find a device for restricting volume such as the AdaptEar - though this apparently only has 3.5mm jack plug/socket arrangement so I would need double 6.3mm jack converters making a potentially unstable connection arrangement with my amp probably degrading sound quality. Also I would prefer to have a decent headphone amp to start with rather than take what I have already got and stick bits onto it.
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mrarroyo
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Post by mrarroyo on Oct 15, 2011 11:33:39 GMT
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xerxes
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Post by xerxes on Oct 15, 2011 12:03:57 GMT
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Post by pandapops on Oct 15, 2011 18:02:06 GMT
All desktop headphone amps can get way too loud with some headphones, user care is required. Is the problem so extreme with the amp connected to CD player or dock? If not, maybe you are taking a signal from the Technics that has been amplified for a speaker into the headphone amp.
I know if there is a product that 'knows' when the sound is too loud for a particular pair of headphones, there the things that just stick a resistor in the signal path and make it a bit quieter, and protection circuits that cutout DC.
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Post by albroun on Oct 16, 2011 19:31:47 GMT
Yes I am in the UK - in the Highlands which is why it is very tricky for me to try anything out as there are no shops for miles and miles!
Many thanks for the offer to send me a pair for trial. As you are only asking £20 I would probably keep them anyway as I like to keep sets of audio spares of this nature - they always come in handy sometime. Do you have a Paypal account I could use to pay you? Presumably I can send you an email with my address details via the forum system?
One other thing I am considering is getting new (and better) headphones with much higher resistance e.g. 600 Ohms - dont know how much difference this would make, but perhaps combined with RCA Line-In attentuators might do the job.
Just one thing - would attenuators degrade sound quality in any way?
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xerxes
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Post by xerxes on Oct 17, 2011 17:14:59 GMT
There is obvously an extra resistor in the signal path, plus the extra connections, so they would in theory effect the sound, however, from recollection, other than the reduction in volume I didn't really notice any detrimental effects.
Send me a PM with your address and I'll dig them out and pop them in the post.
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