Tracing The PeeCeeBee
- Thread starter shaan
- Start date
Shaan, this Pre Amp circuit uses a pretty noisy opAmp, the NE5532. Is there any other circuit which uses lower noise op amps?
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I was thinking about OPA2604AU.
Distortion 0.0003%
Noise 10nV
Slew rate 25V/uS
NE5532
Distortion not stated
Noise 5nV
Slew rate 9v/uS
Joshua, youre right, the NE5532 is low noise. OPA has better distortion, though.
Distortion 0.0003%
Noise 10nV
Slew rate 25V/uS
NE5532
Distortion not stated
Noise 5nV
Slew rate 9v/uS
Joshua, youre right, the NE5532 is low noise. OPA has better distortion, though.
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Well, OPA2134 has 0.00008%, 20V/uS, 8nV/sqrtHz. But this difference of zeros will hardly ever come into play in audio application. Also, both 5532 and 2134 drives 32R headphones equally well. Considering their price difference though, makes me think. 
p.s. I have measured 5532's THD to be less than 0.001% at 1KHz 2VRMS into 10K load.
p.s. I have measured 5532's THD to be less than 0.001% at 1KHz 2VRMS into 10K load.
HormusPeston
Active Member
I concur with Shaan. The "noisiness" of your average 5532 is low enough. They are used (in the hundreds) in professional mixers.
Cheers,
~HP
Cheers,
~HP
It sounds a little better with open and clear vocals. Bass is little tight and heat sinks get hot with 1 hr of play not so much as my other class A amps like the SX or the Aleph.
Well, OPA2134 has 0.00008%, 20V/uS, 8nV/sqrtHz. But this difference of zeros will hardly ever come into play in audio application. Also, both 5532 and 2134 drives 32R headphones equally well. Considering their price difference though, makes me think.
p.s. I have measured 5532's THD to be less than 0.001% at 1KHz 2VRMS into 10K load.
Guys,
there's lot more than what datasheets say. have a look:
NwAvGuy: Op Amp Measurements
http://www.ac-vogel.de/Download/Download/Audio%20Opamps,%20fact,%20no%20myths%20and%20THD%20measurement%20results.pdf
Regards,
Aniket
Since cost per piece is reasonable, it will be better to switch to a lower noise LM4562 for audio applications. The author also says that if the price falls, this IC will replace NE5532.
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...There seems to be a "universal" agreement of better sonics with the Exicon FETs around the net. Time to check it out (however, I am expecting zero difference
I have compared four channels for about half a day. Two with K/J pair and two with 10N/10P pair, other components and PSU being the same. I could only notice a slight improvement in the lowest octaves. Above about 50-60Hz everything sounds the same between them, indistinguishable. A relief I must say. There are no audible clipping artifacts with the new pair as well as the old. I am however, not 100% sure that the difference in the low octaves are due fully to the MOSFETs as the ECXs are running with Panasonic FM and the K/J with Panasonic M+FC.
I must admit that I have been listening to V4 with the old pair for more than 3 months on an everyday basis now and for a "genuine" subjective idea of the sonic differences with the new pair I need to give them a long listen (shouldn't be a problem, festive season is close and my house is far from the noises).
I noticed during biasing that the ECX pair doesn't need that many turns of VR3 to reach 100mA. A real good thing. Thermal stability is just fine. Measurements will follow soon.
...to be continued later.
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A fresh CRC PSU to power the PeeCeeBees (or any other amplifier) and also protect the speakers at the same time, is here!!!
Hi Shaan da, finally had time yesterday to wire up the amps and play them... My God .. was blown away by the performance.. a very fine amplifier I must say and thank you very much for all your help..
May I please have more details about the Power supply ??
Best wiskes,
Lifewater
Hi Kaushikda.
I's happy to know the V4s are playing well and you like the sonics! Can't imagine a more pleasant day! Thanks for sharing your thoughts!
Here are details of the new PSU:
It will have two independent fully discrete speaker protection circuits powered directly from the rails with symmetrical loading on both rails. No need for a 12V PSU. Less wirework!
CRC filtering of rails. Meaning extremely low ripple, perfect for Class-A amplifiers, meanwhile automatic bypassing of rail resistors (the R in CRC) during high transient current demand.
Pads for both TO220 and TO247 diodes that can be mounted underboard and fixed on chassis floor requiring no individual heatsinking of the diodes.
Accommodation for relays in different form factors with 10/20/30A contacts if desired and MOSFET driving of relays if desired.
There will be two variations, one for center tapped and another for split secondary transformers (if I can't make one design allow for both).
@Shaan
Usually what is available in the market are either mono or stereo version of the speaker protection modules. And 99% of these modules run with 12V 'AC' and not DC so it has in-built PSU a tiny bridge rectifier module I think which I actually blew if you remember when I accidently powered with 24v. But your PSU gives the added advantage of not running additional AC wiring from the transformer to the speaker protection module(s) and just take it from the PSU itself :clapping:
Order now for just ₹19,990.00
