Author Topic: QSX03 A new RIAA amp with passive RIAA correction  (Read 22109 times)

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Offline peranders

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QSX03 A new RIAA amp with passive RIAA correction
« on: April 15, 2008, 08:11:12 PM »
Specifications of my new RIAA amp project can be found here

Please add ideas and wishes here if you want.
« Last Edit: April 07, 2013, 12:15:32 PM by peranders »
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Offline rclourenco

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #1 on: July 15, 2008, 11:03:00 PM »
 :-D
Fantastic I will wait very nervously for this, by the list of features you publicited it looks very, very promissing.

Another Idea, have you tought about going Battery powererd?

And adjustable gain?

Balanced its a must, the rest very good, please don't forget about the power supply its a must to have the best.

regards,

Offline peranders

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #2 on: July 18, 2008, 10:00:04 AM »
About gain, see item 2 in my wish list!

Battery, no not by me but can't see any problems if you want to use batteries.
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Offline roberto.missoli

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #3 on: December 13, 2008, 05:59:55 PM »
And what about to have Pseudo-Differential input (as an optional configuration)?

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Offline peranders

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #4 on: December 13, 2008, 08:55:55 PM »
Nothing stops you to use the "b" configuration but I will not incorporate a true balanced input just because this is extremely rare.
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Offline enzedone

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #5 on: January 20, 2009, 06:57:28 AM »
I don't know much about this sort of stuff, except I would like it to be switchable between MC & MM without having to open the case and change resistors  and the likes to match up cartridges.
Just my simple thoughts.
Edit: Sorry....just read the title page for this project.........Doh!


Brett.
« Last Edit: January 20, 2009, 07:35:12 AM by enzedone »

Offline sek

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #6 on: April 18, 2009, 04:28:49 PM »
Hi there,

what impedance level can be tolerated in the passive network?

I'm asking because larger resistances allow for smaller capacitances - and this would in turn allow for either high quality and/or small size capacitors.

As an example, I'm thinking of NP0 ceramic capacitors in the network. They are easily available as SMT or thru-hole parts up to around 3.9nF, but not larger.

On the other hand, the network takes physical space to lay out on a PCB, which gives inductance to the board traces. The higher the impedance, the more sensitive the network gets - leading to EMI and increased noise level.

Using capacitors in the single nanofarads brings the series resistor up into the hundreds of kiloohms. Would this be a problem inbetween two opamp stages?

Small, inexpensive, high precision components can never hurt. And the prospective of a tiny PCB routing area with short traces is intriguing. :wink:

Cheers,
Sek.

Offline peranders

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #7 on: April 18, 2009, 05:55:01 PM »
I can't tell you right now but higher impedance will be more sensitive against stray capacitances => not so go RIAA curve unless you can measure it and adjust it accordingly. It's also important to not generate more noise than necessary.
« Last Edit: April 18, 2009, 05:59:31 PM by peranders »
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Offline byggareandy

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #8 on: September 23, 2009, 07:30:00 PM »
Hi, I'm about to build me a RIAA amplifier. Is this one to be finished in a near future? /Andreas
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Offline peranders

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #9 on: September 23, 2009, 09:27:41 PM »
I'm afraid we are talking about the distant future right now.
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Offline enzedone

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #10 on: September 23, 2009, 11:56:11 PM »
Good things come to those who wait..... :-D

I lost money on Rhys,s 'Phono 3' boards GB. Money I'd rather have spent on my little boy.
So no more rubbish projects for me. I'll just wait for this project to be completed. And at least I know that it will be well produced and well organised and honest.
Peranders, your boards are always very nice.... :-). Thanks for producing them for idiots like myself with no ability.


Offline peranders

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #11 on: September 24, 2009, 06:35:30 AM »
Thanks, but the hope for Rhys isn't completely gone. If stuff turns up here tomorrow, there will be some hope after all.
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Offline byggareandy

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #12 on: September 24, 2009, 10:39:36 AM »
What will the main improvements be from your QSX Mark III? Is there something outstanding with your new RIAA that would make it worth waiting for. /Andreas
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Offline peranders

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #13 on: September 24, 2009, 09:24:28 PM »
Using passive correction is just an another flavor. That's all.
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Offline goldkenn

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Re: QSX03 A new RIAA amp with passive RIAA correction
« Reply #14 on: November 08, 2009, 10:11:20 AM »
Any news update?