6080 OTL Headphone amp

For anything about cans, and the amplifiers that drive them
User avatar
Nick
Site Admin
Posts: 15707
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#1 6080 OTL Headphone amp

Post by Nick »

I have been reminding myself about the OTL phone amp I have been playing with. I am unsure (not being a long time headphone amp user) if it produces enough power to be useful. Hopefully those out there who use phones will let me know if this power outputs are any use or not.

Impedance - RMS voltage - Power out 1kHz two chan

300 ohm - 13.1v - 0.57W
150 ohm - 8.9v - 0.53W
64 ohm - 5.5v - 0.48W
32 ohm - 2.9v - 0.26W
16 ohm - 1.4v - 0.124W

Output impedance is 13 ohm
Last edited by Nick on Sat Jan 01, 2011 3:29 pm, edited 1 time in total.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
Toppsy
Shed dweller
Posts: 2400
Joined: Mon Jul 23, 2007 12:10 pm
Location: red rose country

#2

Post by Toppsy »

Nick, not sure, but I use the WAD HD83 to drive my Sennheiser HD650 headphones, which are 300-ohm.

Here are the specs for these: http://www.sennheiser.co.uk/uk/home_en. ... nes_009969

May help.

You are welcome to borrow the HD650's for experimental purposes.

Colin
User avatar
Nick
Site Admin
Posts: 15707
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#3

Post by Nick »

Yes, it would be helpfull to borrow them some time Colin. Thanks.

I will measure the amp at 150 and 300 ohm for reference.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
Mike H
Amstrad Tower of Power
Posts: 20157
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#4

Post by Mike H »

Guess it depends what headphones, but for "ordinary" ones I've noticed tends to be about 45mV.

'Least that's what's written in the service manual for my cassette recorder IIRC, as an example.



 
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
User avatar
Nick
Site Admin
Posts: 15707
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#5

Post by Nick »

I have updated the original post to add 150 and 300 ohm
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
cressy
Shed dweller
Posts: 2906
Joined: Fri Aug 03, 2007 7:07 pm
Location: the great white space
Contact:

#6

Post by cressy »

hi nick, i can send you up my big old sony headphones if you want them, ive no use for them (been replaced) and id assume they were pretty average in terms of specs if you want them

cheers ant
User avatar
Toppsy
Shed dweller
Posts: 2400
Joined: Mon Jul 23, 2007 12:10 pm
Location: red rose country

#7

Post by Toppsy »

Yes, it would be helpfull to borrow them some time Colin. Thanks.
Nick,

I could bring them over one day/evening next week, if that's OK?

I can collect and pay for the Start-up boards at the same time, hey :wink:
User avatar
colin.hepburn
Shed dweller
Posts: 2294
Joined: Sat Jun 02, 2007 1:24 am
Location: Scotland Aberdeenshire

#8

Post by colin.hepburn »

There's the Spec for my Headphone Amp if it helps I Use my Sennheiser HD650 /300 ohms with it
Attachments
12B4A.jpg
Colin
The Blues man ImageImage
User avatar
Nick
Site Admin
Posts: 15707
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#9

Post by Nick »

Thanks for the offer Ant, I may take you up on that later, I have the ones that were the free giveaway from HFW some time ago (second pair, Dave donated his to me).

Colin H, thats very useful. Looks like the voltage into 32 ohm is ok then, good, I will carry on trying to get the diag into a state and then write some text for it.

Colin T, That would be great, given you have found a excuse to come over :-). Any evening will be good for me.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
colin.hepburn
Shed dweller
Posts: 2294
Joined: Sat Jun 02, 2007 1:24 am
Location: Scotland Aberdeenshire

#10

Post by colin.hepburn »

Hi Nick
Here's a Link to the 6AS7 Headphone amp I was intending to build some time ago but it is still on the back burner of projects to build it give some measurements that my be of help its about half way down the the page http://gilmore2.chem.northwestern.edu/p ... e1_prj.htm
Colin
The Blues man ImageImage
User avatar
Nick
Site Admin
Posts: 15707
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#11

Post by Nick »

Yes, that also helps Colin, its good to have comparisons. I feel better about the power output of what I have now, seems to be enough. Sounds nice anyway. Cristal clear in that OTL way. I will look forward to seeing how it works with Colin T's better cans.

The circuit I have is more complex that the one you linked, but I wanted to play with a push pull sort of OTL stage as a alternative to the cathode follower type you linked to. Its two ECC83's and two 6080's +- 200v and +- 120v power supplies.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
Blagdon75
New User
Posts: 2
Joined: Sat Jan 15, 2011 5:59 am

#12 Re: 6080 OTL Headphone amp

Post by Blagdon75 »

Nick wrote:I have been reminding myself about the OTL phone amp I have been playing with. I am unsure (not being a long time headphone amp user) if it produces enough power to be useful. Hopefully those out there who use phones will let me know if this power outputs are any use or not.
...
My advice to you is you can try using it though you are not so sure about it. We don't like to lose a headphone or amp. Best thing to do is to read the manual of the amp before using it.
Last edited by Blagdon75 on Wed Jan 19, 2011 7:13 am, edited 1 time in total.
User avatar
Nick
Site Admin
Posts: 15707
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#13

Post by Nick »

Err, Maybe reading the thread would help. I was talking about the design of a amp.

Anyhow, Colin has kindly lent me his high impedance headphones, so I have tried both ends of the range. Still writing up the text for it at the moment, next is to add some schematics.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
Nick
Site Admin
Posts: 15707
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#14

Post by Nick »

The doc with the design is up now

http://www.hificollective.co.uk/pdf/otl_head.pdf

Thanks to those who helped with the proof reading.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
Mike H
Amstrad Tower of Power
Posts: 20157
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#15

Post by Mike H »

Whoo, cool. Image

 
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
Post Reply