Try the NE5534 (Philips version preferably) rather than the 5532. It should cost much more and the results are excellent. 😉
gengcard said:
It sounds like
.gengcard said:
It sounds good, but not as good as a OPA627 of even a OPA2134.
As I replaced my schematic file, even in the posting before you see now the actual schematic, wich sounds VERY fine:
Differences now:
- no more coupling cap, DC-coupled (the grid is on zero potential)
- More gain, a little bit to much (will reduce Rf from 10K to 6.8K.
- Overall feedback
- now 3Watt output on 8 ohm, before SOFT clipping starts
I think, it is now one of my best sounding amps and I will convert the second one soon.
But, maybe, I will finish first this real tube amp (was in the pipeline some time now), a PL519 single end in enhanced triode mode:
Franz
An externally hosted image should be here but it was not working when we last tested it.
Differences now:
- no more coupling cap, DC-coupled (the grid is on zero potential)
- More gain, a little bit to much (will reduce Rf from 10K to 6.8K.
- Overall feedback
- now 3Watt output on 8 ohm, before SOFT clipping starts
I think, it is now one of my best sounding amps and I will convert the second one soon.
But, maybe, I will finish first this real tube amp (was in the pipeline some time now), a PL519 single end in enhanced triode mode:
An externally hosted image should be here but it was not working when we last tested it.
Franz
Carlos
I agree: the OPA627 or 637 fits in very good audio systems.
But (please, people, dont kill me! I know, I am in the Chip Amp forum...):
This LM3xxx chips, I don't really like them! As I mentioned before, the asymetrical outputstage of this chips is the bottleneck for real high end.
So, what is the "gain" to put the best opamp as a buffer in front of a not perfect powerstage?
I did not try other poweropamps up to now.
I would recommend to all owners of fullrange speakers, like Fostex FE206E in backloaded horn, coral beta, lowther and so on, to forget about this poweropamps and to build a hybrid like shown.
You will be surprised!
Franz
I agree: the OPA627 or 637 fits in very good audio systems.
But (please, people, dont kill me! I know, I am in the Chip Amp forum...):
This LM3xxx chips, I don't really like them! As I mentioned before, the asymetrical outputstage of this chips is the bottleneck for real high end.
So, what is the "gain" to put the best opamp as a buffer in front of a not perfect powerstage?
I did not try other poweropamps up to now.
I would recommend to all owners of fullrange speakers, like Fostex FE206E in backloaded horn, coral beta, lowther and so on, to forget about this poweropamps and to build a hybrid like shown.
You will be surprised!
Franz
Nice schematic, saw it before somewhere but with a different opamp ( NE5534 ).
Some remarks: you could use a 100k or 220k resistor from the non-inverting input to ground ( imagine what will happen if the wiper has a bad day ). The use of an RC filter at the input is preferred as OPA627 has quite a high bandwidth and it likes a series resistor too at its input. Make that filters -3 dB point around 100 kHz.
Probably the use of an input cap ( when it is unknown whether the source is DC free or not ) would be a wise choice but when it can be avoided you should avoid it of course. Did you listen to it like it is now without the 47k overall feedback resistor ?
BTW I don't understand your remark on the asymmetrical output stage of the LM3xxx series when I think of Single Ended tube amps ( or even more: balanced tube amps ) !?!?!
Some remarks: you could use a 100k or 220k resistor from the non-inverting input to ground ( imagine what will happen if the wiper has a bad day ). The use of an RC filter at the input is preferred as OPA627 has quite a high bandwidth and it likes a series resistor too at its input. Make that filters -3 dB point around 100 kHz.
Probably the use of an input cap ( when it is unknown whether the source is DC free or not ) would be a wise choice but when it can be avoided you should avoid it of course. Did you listen to it like it is now without the 47k overall feedback resistor ?
BTW I don't understand your remark on the asymmetrical output stage of the LM3xxx series when I think of Single Ended tube amps ( or even more: balanced tube amps ) !?!?!
Franz G said:
If you need to use a gain of 5 or more, you can use the 637.😉
Oh yes...
Franz G said:
Nah.😀
You're a 😎 guy, you're just searching for the best for your system, like all of us.🙂
We won't kill you claiming LM3xxx not being high-endFranz G said:
But I think you may agree on that those chips makes it very easy for many people to build a rather good amp.peranders said:We won't kill you claiming LM3xxx not being high-end
Just looking at the Gaincard's price, I would call it "high-end"!😱
Of course quality doesn't have a direct relation to price, but...
Ok, it's a che(i)ap amp with a high price.😀
I got some SSM2019 balanced driver, audio chips in last week from Digikey -- debating whether to use this or the AD797 for repairing my HP465 low noise preamp.
The SSM2019 is claimed to have 1nV Rt Hz noise, THD 0.001% and it costs way less than the OPA627. This would be a very good low noise input for the GC., or any preamplifier for that matter.
Jack
The SSM2019 is claimed to have 1nV Rt Hz noise, THD 0.001% and it costs way less than the OPA627. This would be a very good low noise input for the GC., or any preamplifier for that matter.
Jack
jackinnj said:
You really have to listen.
The AD797, athough good, doesn't sound to me nearly as good as the OPA627.
It would be nice to pick a chip just by the specs, so much easier.
Just curious, is it better to use the opa627 as a buffer or with gain, if so, how much gain. This is for the input of a GC, of cause.
ChuckT said:
There are plenty of possibilities...
I use it as a buffer, but you could even use the OPA637 with a gain of 5, and decrease the gain at the power op-amp chip.
carlosfm said:
Oh really? Is open loop or high gain behaviour of 3886 that perfect? 😉 (especially distortion, but someone likes it distorted).
the LM chip is not one of those amps that work with no feedback , it is designed to work with feedbacktbla said:
PMA said:
You can't go lower than 10x gain...
Do you think it would be a good idea to use an OPA637 with 5x gain and an LM3886 with, say, 15x gain?
I didn't test it, but it may work fine (better?).
As I said, plenty of possibilities...😀
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