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Klon buffer IC change.ANy change in parts?

Started by garfo, April 05, 2014, 12:48:17 PM

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garfo

I'm building a Klon buffer to use as a buffer following an active onboard preamp.I need a buffer that will Recover from using a passive blend and volume pots post preamp.I'm currently using a discrete bjf buffer but I believe I can benefit from better output using an opamp buffer.
So, the Klon buffer seems a good simple alternative.
Anyways, I wanted to replace the TL071 with a better audio opamp such as OPA134.
If I do so, would I need to change anything or add anything to the opamp to perform better?
Also is there anything out there that will perform better than the TL071 and still draw less than the 5mA which is the reference for the opa134!?
I have checked several options but apparently I would need to make some fixes to the design to make the buffer act better within the IC specs.

garfo

Quote from: garfo on April 05, 2014, 12:48:17 PM
I'm building a Klon buffer to use as a buffer following an active onboard preamp.I need a buffer that will Recover from using a passive blend and volume pots post preamp.I'm currently using a discrete bjf buffer but I believe I can benefit from better output using an opamp buffer.
So, the Klon buffer seems a good simple alternative.
Anyways, I wanted to replace the TL071 with a better audio opamp such as OPA134.
If I do so, would I need to change anything or add anything to the opamp to perform better?
Also is there anything out there that will perform better than the TL071 and still draw less than the 5mA which is the reference for the opa134!?
I have checked several options but apparently I would need to make some fixes to the design to make the buffer act better within the IC specs.Would the klon buffer justify the extra power draw?

Clayford

Perhaps you have golden ears or I have tin ones...

But I have a tl072 klon buffer on my board and after the first day forgot it was there.
head solder jockey, part time cook: cranky&jaded

garfo

#3
I see your point.I'm not complaining about the tl07 type.Is just that I know there are supposed better audio dedicated modern IC's.I've never really ab'd them and probably wouldn't find an audible difference.And Also, I'm actually in doubt if I would really benefit from an IC buffer.For me the bjt discrete buffer has one advantage, it consumes way less power, and If the difference isn't too big, then perhaps I could do well with the discrete buffer.
Anyway, I'm just askin, there are a lot of people on this forum whowho know way more than meself.

RobA

Kind of as a general rule, if the op-amp you want to replace has a FET input, you can replace it with other FET input op-amps. There are certain situations where that's not true, like if you need rail-to-rail, but as far as the general audio path of the circuit is concerned, it's not a horrible rule.

The TLE2071 should work and its supply current is about 1.6mA. If you can go with a dual op-amp, there are more choices. Also, if you can use an SMD part, either by an adapter or using a different PCB, there are also more options.

If you can use a dual, the TS922 is great. It has a ton of drive, is rail-to-rail (lots of headroom) and it's cheap. it is getting to be harder to find in non-SMD form though.
Affiliations: Music Unfolding (musicunfolding.com), software based effects and Rock•it Frog (rock.it-frog.com), DIY effects (coming soon).

garfo

I'll be using the single version.I remember we talked before.At the moment I have a bjt discrete buffer, would I really benefit from an IC buffer?the intention is to have no colorization of the Sound, consume little power and drive the signal well.

RobA

Quote from: garfo on April 05, 2014, 05:02:28 PM
I'll be using the single version.I remember we talked before.At the moment I have a bjt discrete buffer, would I really benefit from an IC buffer?the intention is to have no colorization of the Sound, consume little power and drive the signal well.

So, the buffer is onboard the instrument? To me, op-amp versus BJT for an output buffer is more a matter of taste. I can hear differences and it is different using different op-amps and different transistors, but what I've ended up going to on all my instruments that have active on board electronics is a JFET buffer into a BJT for output drive. If I don't need gain, then I just do an emitter follower for the BJT. If you need more drive, then you could use something like a Darlington or maybe just go with a 2N2222 or something like that, but I've found that using a simple BC550C or BC549C works fine for me. 

Affiliations: Music Unfolding (musicunfolding.com), software based effects and Rock•it Frog (rock.it-frog.com), DIY effects (coming soon).

RobA

As an example, this is what I've got on my Godin A6 (link at bottom). There are two pickups, a Benedetto magnetic and a DIY piezo on the soundboard. The output is split stereo, so there is no mixing, but I wanted the output level to be the same anyway. So, the piezo has a bunch of gain and the magnetic is just buffered. There are some trimmers on the JFET's that probably wouldn't be needed, but I wasn't sure of the transistor I was going to use so I wanted a bit of flexibility. The LED and the power switch are on there because the stereo pot is used for stereo so I can't use it for switching. The LED's are on the slide pots, so they are actually kinda slick.

It's pretty simple and uses very little current and I really like the results.
http://rock.it-frog.com/Downloads/Graphics/godin_pre.pdf
Affiliations: Music Unfolding (musicunfolding.com), software based effects and Rock•it Frog (rock.it-frog.com), DIY effects (coming soon).

garfo

Actually I might leave the discrete buffer there since the other onboard electronics are power suckers, even using low power IC's.