Respectfully, Why would C1 and R1-6 impact sound quality (other than the possibility to induce noise into the circuit) as these all go to ground? 🙂
That's why I suggested that you study the "voltage divider" concept.
In fact, they will all have a substantial effect on the sound of the cartridge, because the signal voltage
at the preamp input depends strongly on how those parts interact with the cartridge's internal impedance,
through voltage divider action. Why else would there be a range of choices for the cartridge load resistance?
Many preamps also have a range of choices for the load capacitance as well. But good capacitors are more expensive.
Both affect the response.
Look at any EE101 text.
In fact, they will all have a substantial effect on the sound of the cartridge, because the signal voltage
at the preamp input depends strongly on how those parts interact with the cartridge's internal impedance,
through voltage divider action. Why else would there be a range of choices for the cartridge load resistance?
Many preamps also have a range of choices for the load capacitance as well. But good capacitors are more expensive.
Both affect the response.
Look at any EE101 text.
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Ok. I'm not debating that when you alter the cartridge loading that it wouldn't impact the sound of the phono stage but none of these (R1-R6) are 'in series' with the circuit. It wouldn't matter if R1-R6 were metal film resistors or tooth picks as long as the values are complementary to the needs of the cartridge right? Again, no matter which position R1-R6 is selected if one used a carbon comp resister vs a Z-foil there wouldn't be any appreciable change in sound quality as long as the value matched the needs of the cartridge. In contrast, R10 is the first resistor in series and IMHO a carbon comp vs a Vishay Z-Foil in this position would greatly impact the overall sound of the circuit would it not? Am I missing something?
This is a discrete op-amp with RIAA feedback. Everything has a role to play, and there are reasons for each value. Perhaps you need to read about op-amp internal operation. Your discrete op-amp is symmetric, but that is not necessary and a mixed blessing. If you just want to make a phono pre-amp, pick a decent op-amp and add the feedback network, input resistors, and maybe the output build-out resistor. If you use a bipolar supply, the output cap is probably not necessary. The "signal path" in any amplifier is a series of current loops where the decoupling capacitors are just as important as the transistors. Each transistor is part of two current loops.
Hi Steveu, Thanks for the reply. I probably should read up on the internal operation of op-amps however the Aragon 47k is fully discrete there are no op-amps in the unit. I understand that "generally" everything in the circirt "makes a difference" my orginal question I posed to the community (I'll re-phrase) is "which (in series) resistors/capacitors (outside of the RIAA) are most likely to impact sound quailty in this circuit?" Let me give an example, The first input resistor R10 is RN55 1% dale metal film. If we replaced this resistor with lets say an old Allen Bradley style carbon comp resistor It might not be the best choice as carbon comp resistors can be a bit noisy right? And, since R10 is very early in a low level circuit one would then assume all that noise would be increased by the later gain stages (bad right?). However, if we replaced R10 with TX2575 series Vishay Z-foil (a resistor known to be exceptionally low noise and very transparent) we might gain in the overall sound quality and reduce the overall noise in the circuit. I'm really puzzed why no one seems to be getting this. 🙄
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I very much doubt the noise generated from a 25.5ohm (apparently they bought tons of these 🙂 ) resistor can be measured, but of course changing the resistor types will have an effect upon the the sound. The most obvious resistors to upgrade imho are R10, R27 (value not critical), the cart loading resistors, precision again not critical, the gain setting resistors (only need to be matched between channels) and of course the riaa resistors which need to be accurate.
Would a simple discrete opamp design justify TX2575 resistors i am not sure, perhaps not.
There is lots in what Steveu was telling you that deserves re-reading.
The thing is: this IS an Op-Amp, plus gain/EQ setting and power networks. Opamps existed before chips, before MOSFETs, before transistors.
Yes.. I get it. Perhaps I should have call it closed loop voltage inverting summing differential integrator differentiator converter detector. Usually when I see the word 'op-amp' it refers to an integrated circuit, enclosed in plastic, with little pins sticking out. They do seem very popular in this forum. 😵
Here's a thought: Buy the parts for maximum upgrades for both channels, but install just one set. Connect each pre-amp output, both the modified and the unmodified, to the same left or right channel of the next piece of gear, but a different line in. Then invite over 3 of your audio hobbyist friends and see how many can discern the difference without seeing which way you crank the selector knob.
Probably just me, but I'd find something I cared less about just to practice soldering on.
Best Regards
Probably just me, but I'd find something I cared less about just to practice soldering on.
Best Regards
Good thoughts Rick. Thank you for the feedback. Well, my soldering skill are fairly competent. I haven't lifted any pads in long time (knock on wood). I say, "practice my soldering skills" as an excuse to spend $$$ on boutique diy parts and hack stuff up.
The members here have given some excellent technical information regarding that Aragon preamp to diginoob.
And upon doing some further research, the preamp as shown is of high quality with impressive specs already carefully designed by the engineers of this preamp.
With that said, I see no honest sonic benefit to changing anything about its original design, let alone any problematic electrolytic capacitors due to aging/tolerances.
And upon doing some further research, the preamp as shown is of high quality with impressive specs already carefully designed by the engineers of this preamp.
With that said, I see no honest sonic benefit to changing anything about its original design, let alone any problematic electrolytic capacitors due to aging/tolerances.
Curious. Why do you say that? To clarify, I've been referring to selected component 'quality' not component 'values' or 'circuit topology.' You're looking at the schematic and gleaning that there's nothing that "no sonic benefit to changing anything". I mean really? The most obvious to me is unit has ginormous 10uf Polyester output capacitor you don't think upgrading this would led to any sonic benefit?
Discussions on previous threads elsewhere regarding "perceived audio results" have been beaten to death already.
And even my own occasional experimenting at the shop has confirmed a lot of snake oil exists out there in the virtual world.
One guy touts some "Audio Gold" component made his life different, and a whole brigade will follow like sheep.
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(answering post #34) Well, wiseoldtech did say, ". . upon doing some further research . .".😉
I'm not sure you need our opinions if the objective is simply buy "boutique diy parts and hack stuff up".
Regards
I'm not sure you need our opinions if the objective is simply buy "boutique diy parts and hack stuff up".
Regards
Right.. Ok. But this IS a diy "Audio" forum right? I mean food for thought here. Isn't audio mostly about perception? How we hear things? Right? I mean should I just hook up my speakers to my refrigerator and listen to that? It measures great. At 34deg all day long, never changes. Is the improvement in speaker manufacturing, and structural and component quality over the last 50 years all just "snake oil?" Really?
So... for those who care. I've selected and received my components/parts for the Aragon 47k upgrade. Shout out to great people at Part ConneXion.
In summery I decided to make this upgrade non-exhaustive. In stead of repaing ALL of the resistors with Z-foils I'm just doing one pair. Here is list of changes in case you acquire one these incredible phono stages and wish to the same. I really consider this vintage of Aragon the "Shindo of SolidState".
Other then caps replacement to the outboard IPS power supply the following updates will be applied to the below pic of the stock/OEM board
1.) The two big 10uf yellow polyester output/DC blocking cap/s.... things.
-upgrade to MPP AuriCap XO, (10uf same value). I chose the AuriCap because it was the best quality cap that would fit in the same OEM footprint/area without looking ridiculous.
2.) Two big power supply caps (not shown) will be replaced with CDM381LX of same value.
3.) 6 small electrolytic caps will be upgraded to Audio Notes with increase of 1200uf per cap. Because I can.
4.) C2a and C2b ( the two yellow upright NP electrolytic will be replaced with MUSE NPs of the same value (green cap)
5.) The input resistors R10a/R10b will be upgraded to Vishay Z-foils of same value.
6.) The final resistors before the output caps R27a/R27b will be upgrade to audio note tantalum resistors. My choice here to is to add just a touch of warmth to the sound and avoid overly sterile sound.
Basically, when everyone is touting opamp phono stages built in Altoid boxs one still has the ability to pick up a beautiful vintage piece of gear and for a few $ upgrade and make something competitive against the finest gear out there today.
It may be a few weeks before I can report back the results and upload it to the lowpower audio youtube channel. More to come!
In summery I decided to make this upgrade non-exhaustive. In stead of repaing ALL of the resistors with Z-foils I'm just doing one pair. Here is list of changes in case you acquire one these incredible phono stages and wish to the same. I really consider this vintage of Aragon the "Shindo of SolidState".
Other then caps replacement to the outboard IPS power supply the following updates will be applied to the below pic of the stock/OEM board
1.) The two big 10uf yellow polyester output/DC blocking cap/s.... things.
-upgrade to MPP AuriCap XO, (10uf same value). I chose the AuriCap because it was the best quality cap that would fit in the same OEM footprint/area without looking ridiculous.
2.) Two big power supply caps (not shown) will be replaced with CDM381LX of same value.
3.) 6 small electrolytic caps will be upgraded to Audio Notes with increase of 1200uf per cap. Because I can.
4.) C2a and C2b ( the two yellow upright NP electrolytic will be replaced with MUSE NPs of the same value (green cap)
5.) The input resistors R10a/R10b will be upgraded to Vishay Z-foils of same value.
6.) The final resistors before the output caps R27a/R27b will be upgrade to audio note tantalum resistors. My choice here to is to add just a touch of warmth to the sound and avoid overly sterile sound.
Basically, when everyone is touting opamp phono stages built in Altoid boxs one still has the ability to pick up a beautiful vintage piece of gear and for a few $ upgrade and make something competitive against the finest gear out there today.
It may be a few weeks before I can report back the results and upload it to the lowpower audio youtube channel. More to come!
(responding, slowly - at old brain speed, to #37) I don't remember speakers having been mentioned. Not sure what 'structural' you're talking about. Component quality has improved over the last 50 years. But the improvement is only a miniscule fraction of what The Avid Reader of Audio Publications would be led to believe.
More improvement has resulted from such techniques as adding a smaller-value film capacitor in parallel with electrolytic capacitors (especially those used for interstage coupling), and Cascode-connected VAS topologies. And of course there are parts that didn't exist or were expen$ive 50 years ago, like MOSFET's and advanced op-amps. But again, those factors don't address issues in your original query, either. And there have been reliability improvements, too; but once again, largely indifferent to sound quality.
Cheers
More improvement has resulted from such techniques as adding a smaller-value film capacitor in parallel with electrolytic capacitors (especially those used for interstage coupling), and Cascode-connected VAS topologies. And of course there are parts that didn't exist or were expen$ive 50 years ago, like MOSFET's and advanced op-amps. But again, those factors don't address issues in your original query, either. And there have been reliability improvements, too; but once again, largely indifferent to sound quality.
Cheers
Well fair enough. I used speakers as a simple analogy. Perhaps a bad one. I dont think the improvements are minuscule. If anything improvements in manufacturing and component quality have scaled a level of quaity to greater number of consumers. Sure, there are exceptions. Vacuum tubes and Vitaman Q PIO capacitors (which sound better) have taken a back seat to manufacturing costs/scalability right but generally the average enthusiast didn't have access the quality and availability of diy part they do today. And other then a select few manufactures, most will not utilize them as they focus on market costs and profit. Which is fine but unfortunately for the enthusiast. That was my point. Its all like cooking, IMHO. The ingredients make the whole. The ones who bother to listen can today can gain a lot of satisfaction by accessing a level of quailty that wasn't "mostly" available when a lot of this vintange gear was made. Again, IMHO. thanks for the post.