Love those simulations! My 270R will not lead to much deviation from the RIAA-curve, but I'll change them for the intended 220 anyway (and keep the 100 uF). Bit more LF roll-off around 20-30Hz, but also more attenuation in the 5Hz-region which will help combat woofer pumping. I guess that's more useful than 0.3 dB or so @ 20Hz.
Dear Wellerman,
if we want to concentrate on the second stage and on the most optimal dual OP amp, we have to choose a type that also forgives us Q9 in its internally specified mode of operation. If you only want to reduce the gain factor of this stage, you will unfortunately also have to adjust R15 and R4+R17 - with constant C4. So disclose the calculation.
What amplification should this stage provide for you and what value would you like to use as C4?
But now we are really leaving the ORIGINAL - and you can already dress warmly when trying to put together the appropriate resistor values.
Kind regards,
HBt.
if we want to concentrate on the second stage and on the most optimal dual OP amp, we have to choose a type that also forgives us Q9 in its internally specified mode of operation. If you only want to reduce the gain factor of this stage, you will unfortunately also have to adjust R15 and R4+R17 - with constant C4. So disclose the calculation.
What amplification should this stage provide for you and what value would you like to use as C4?
But now we are really leaving the ORIGINAL - and you can already dress warmly when trying to put together the appropriate resistor values.
Kind regards,
HBt.
Number two
If you want to understand the pearls, then someone should take the trouble to explain the first stage in detail, with all the bells and whistles. In the Pearl 2 thread, some users obviously also had a cascode that didn't work properly.
Perhaps Jim would like to take up this challenge.
If you want to understand the pearls, then someone should take the trouble to explain the first stage in detail, with all the bells and whistles. In the Pearl 2 thread, some users obviously also had a cascode that didn't work properly.
Perhaps Jim would like to take up this challenge.
Good catch, thank you. It's a small enough difference with minor adjustments to R18 not to be visible in sim without applying the inverse RIAA curve.
Driving SPICE late at night is a risky enterprise...
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While on the subject of RIAA accuracy - anybody got an LTspice deck for a known good inverse RIAA signal source they're willing to share?
I can build one myself from scratch following the Lipshitz or Hagerman papers, but surely this has already been done a thousand times over.
Searching the forum, I'm not coming up with much. Plenty of long threads on the topic that go deep into the weeds...
I can build one myself from scratch following the Lipshitz or Hagerman papers, but surely this has already been done a thousand times over.
Searching the forum, I'm not coming up with much. Plenty of long threads on the topic that go deep into the weeds...
Might be a good excuse/opportunity to learn about the "LAPLACE" feature of LTSPICE...
No wishes to depart from the original too much. I just wanted to tweak the low-cut filter a bit and in doing so also influenced RIAA compliance a little bit. So I put in the original 221R for R18. As for the opamps: I want to roll some to see if I can hear a difference in sound or amount of hiss. But I want these to be drop in replacements (so mostly stay with the ones that were tested to work in the circuit). No recalculation of entire stages as that is beyond my capabilities.
The R18, C8 thing up in the left hand corner of the op-amp feedback loop is not part of the "required" equalization, it is the IEC amendment, kind of an after thought that is not included in the RIAA equalization.
Can someone confirm that only kits will be for sale shortly, and bare boards will not be available?
Could anyone tell me if the Sparkos Labs SS2590 could be used in the Pearl3 or I really need to go with dual opamp?
I am also curious to hear if someone has tried the Burson V5i here?
I am also curious to hear if someone has tried the Burson V5i here?
If you buy single op amps as smd's you can get adapters that can convert 2 x single to a dual that fits in dip8 socket.
Regarding Burson I think TonyEE has tried most. From memory the V5i was most successful. Burson don't recommend V6 used in riaa MC applications but V5i should be ok.
Regarding Burson I think TonyEE has tried most. From memory the V5i was most successful. Burson don't recommend V6 used in riaa MC applications but V5i should be ok.
Thanks for your quick reply. I assume 2 x SS2590 per channel could also not be the best match in case Burson V6 is not recommended in MC applications.
Do you recall which opamp was TonyEE's favourite?
Do you recall which opamp was TonyEE's favourite?
The perfect dual OP for the Pearl III
Which operational amplifier (dual) would Wayne choose for his EQ if he only had one EQ available, namely the current Pearl III ?
That is the crucial question.
Which operational amplifier (dual) would Wayne choose for his EQ if he only had one EQ available, namely the current Pearl III ?
That is the crucial question.
In case anyone was wondering: the opamp experiment outlined in post #1,396 has been fully enabled. Parts acquired, SOIC-to-DIP adapters installed where needed, parcel shipped to and received by, listening panel coordinator.
I think the idea of the blind test is great, there's something slightly heretical about it.
But personally, I'd be really interested in Wayne's favorite. What type is in the kit, maybe that answers the question.
Just as an aside (without thinking) what would speak against the venerable 741 ?
🙄
But personally, I'd be really interested in Wayne's favorite. What type is in the kit, maybe that answers the question.
Just as an aside (without thinking) what would speak against the venerable 741 ?
🙄