[sdiy] headphone driver for synths

[Mike Bryant]

Checked and it was the section on reducing CM distortion by bootstrapping the rails I was thinking of.   Just as 'out of the box' but a different application.

-----Original Message-----
From: Brian Willoughby [mailto:brianw at audiobanshee.com] 
Sent: 28 August 2021 21:50
To: Mike Bryant
Cc: Roman Sowa; synth-diy at synth-diy.org
Subject: Re: [sdiy] headphone driver for synths

Not in Small Signal Audio Design - I checked the headphone chapter.

Maybe in one of his other books?

Brian


On Aug 25, 2021, at 02:59, Mike Bryant wrote:
> I thought Douglas Self covered this in one of his books
> 
> -----Original Message-----
> Sent: 25 August 2021 08:43
> 
> Has anyone ever tried to explore this not-so-new idea of using opamp's supply currents to drive boosting transistors?
> Schematics attached.
> 
> Roman
> 
> W dniu 2021-08-25 o 01:49, ulfur hansson pisze:
>> you all are amazing, thanks so much for the info!!
>> 
>> sent from outer space
>> 
>> On 24 Aug 2021, at 23:19, Vinicius Brazil wrote:
>>> 
>>> +1 with bd139/140
>>> 
>>> On Tue, Aug 24, 2021 at 7:29 PM Brian Willoughby wrote:
>>> 
>>>    Looking inside gear that I've owned over the years, I have seen
>>>    plenty of purpose-designed headphone amplifier chips. I've never
>>>    designed with them or looked at the pricing, so they might not be
>>>    the best choice for all situations, but they certainly have plenty
>>>    of power and the data sheet example circuits will certainly be
>>>    aimed at driving headphone loads.
>>> 
>>>    Brian
>>> 
>>> 
>>>    On Aug 24, 2021, at 09:49, ulfur hansson wrote:
>>>> hello all!
>>>> 
>>>> i've been getting mixed results for a few yeara using standard
>>>    opamp circuits to drive headphones for my projects. oscillations
>>>    randomly seem to occur, noise issues that disappear if i use nice
>>>    outboard preamp etc...
>>>> 
>>>> is there a more juicy/capable solution anyone can think of? THAT
>>>    corp line drivers? discrete transistor drivers?
>>>> 
>>>> any thoughts would be greatly appreciated :) -ulfur