QUOTE]time to go active with some chips inside. [/QUOTE]
dear carlos.......i'm workin' on it, but the active/electronic filter worries me - a lot...!
i am a firm believer that very few people of this world can design a loudspeaker/filter that really works - and i'm NOT one of them...
here and it seams that it's the same all over Europe.
See you guys in two weeks.
I'll
for you.😀
Well guys, time to go to the beach.😀
It's
here and it seams that it's the same all over Europe.See you guys in two weeks.
I'll
for you.😀tbla said:
With the right woofer you don't even need a crossover (or active filter).
You just need it for the tweeter.
NOW I'm gonna
.
I haven't noticed this thread yet 🙂 🙂 and probably I should have ... Have found one of my circuits here ... OPA627 is really the best choice with BUF634T. In case of using OPA637 please take to the account that it is not unity gain stable, the gain must be 5 or more.
Pavel
Pavel
Hi guys.
I came back from holidays, but I have so much work to do (at my job), that for some time it will be difficult to come here as often as I would like.
Here's a simple mod I did to my pre.
C1 cap should be 200pf.
It sounds even better, specially the treble is smoother and even more detailed.
I consider this ESSENCIAL for any fast op-amp working with the BUF634.
And it's on the datasheet.
Now, some of these days I've gotta compare my pre to that Jeff Rowland Coerence again.
I came back from holidays, but I have so much work to do (at my job), that for some time it will be difficult to come here as often as I would like.
Here's a simple mod I did to my pre.
C1 cap should be 200pf.
It sounds even better, specially the treble is smoother and even more detailed.
I consider this ESSENCIAL for any fast op-amp working with the BUF634.
And it's on the datasheet.
Now, some of these days I've gotta compare my pre to that Jeff Rowland Coerence again.
Attachments
This cap isn't crucial but it's good to use it though. I have tested my headphone amp with and without this cap in meduim and high speed mode and also with AD8610. I got no problems with oscillations but to be sure I would still recommend it, especially if you don't have a good pcb.
It just sounds better to my ear.
At least with the OPA627.
PMA, I use a gain of around 2.4x, and the OPA627.
Yes, the 637 is stable only at gains of 5 or more.
At least with the OPA627.
PMA, I use a gain of around 2.4x, and the OPA627.
Yes, the 637 is stable only at gains of 5 or more.
Hi carlosfm,
I have done a lot of measurements regarding C1. In case that I use feedback resistor of 3.3k and the same value of resistor from (-) input to GND, the C1 capacitor's optimal value is 18pF. This is valid for OPA627 and OPA134. In case that you use AD825, no C1 should be connected.
Pavel
I have done a lot of measurements regarding C1. In case that I use feedback resistor of 3.3k and the same value of resistor from (-) input to GND, the C1 capacitor's optimal value is 18pF. This is valid for OPA627 and OPA134. In case that you use AD825, no C1 should be connected.
Pavel
A bit off topic here, but its still in relation with quality preamps and GC.
How would a BOZ work with a GC?
What would need to be the input impedance of the GC to make it match?
How would a BOZ work with a GC?
What would need to be the input impedance of the GC to make it match?
Well,
Actually is kind of a LPF, isn't it?
BTW, Welcome back Carlos, I hope you've had nice holidays.
Actually is kind of a LPF, isn't it?
BTW, Welcome back Carlos, I hope you've had nice holidays.
Raka said:
Not exactly LPF. It is the way of global negative feedback stabilization. It results from second opamp (buffer) present inside feedback loop. The same way of compensation is often used for capacitive loads.
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