I like it too but not all carts are happy playing into a short. Most of the Ortofons sound good, the Denon 103 - less so. Interestingly, the more ambitious diy projects seem absent from this thread.
It's still a fair question, my turntables' cartridge is directly wired to the output, it does not pass go, it does not go to jail and it is not connected to anything else.
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I like a picture of the schematics. I see all ingredients high qaulity parts in the cooking-pot.
I like this smart simple one.
An externally hosted image should be here but it was not working when we last tested it.
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Hi,
I and probabely most listeners and owners of the PlatINA have very different sonic impressions about the INA103/INA163 as analog-SA reported in #31.
All the guys who built it reported extremely well defined and lively bass as one of their first impressions and nobody complained about the highs but one guy, who had switched a too high capacitance load to his MM-Pickup. When he corrected it, he reported well above average highs quality too. I rather assume some weaknesses within that circuit analog_SA listened to rather than incapabilities of the INA103. Already slight deviations from the playback equalization curve and tonality and as such sonic impression changes alot.
Anyway, the remarkable think to mention about the INAs is the possability to run the pickup into a symmetrical Input. MC pickups -as symmetrical sources- profit from the noise-immunity of a balanced setup.
At the time there´s hardly any more modern equivalent instrumentation amplifier than the SMD-Version of the INA103, BB/TI´s INA163. ADIs AD8229 is too new as release and certainly does not look any better on paper.
jauu
Calvin
I and probabely most listeners and owners of the PlatINA have very different sonic impressions about the INA103/INA163 as analog-SA reported in #31.
All the guys who built it reported extremely well defined and lively bass as one of their first impressions and nobody complained about the highs but one guy, who had switched a too high capacitance load to his MM-Pickup. When he corrected it, he reported well above average highs quality too. I rather assume some weaknesses within that circuit analog_SA listened to rather than incapabilities of the INA103. Already slight deviations from the playback equalization curve and tonality and as such sonic impression changes alot.
Anyway, the remarkable think to mention about the INAs is the possability to run the pickup into a symmetrical Input. MC pickups -as symmetrical sources- profit from the noise-immunity of a balanced setup.
At the time there´s hardly any more modern equivalent instrumentation amplifier than the SMD-Version of the INA103, BB/TI´s INA163. ADIs AD8229 is too new as release and certainly does not look any better on paper.
jauu
Calvin
Hi,
As you can see, you get as many different recommendations as there are people making them.
Over time I probably have build about any possible configurations. Many Phono's can sound good. You need to decide on some ground rules to pick something worth making.
I found I like best circuits with low or no negative loop feedback, where looped feedback is used keeping the feedback factor reasonably constant with frequency is preferable to one that varies widely. Inherent linearity nearly always beats using more feedback.
I like passive LCR based EQ best.
Tubes generally do better than transistors and Fets, subjectively speaking, but some unconventional solid state circuits are also very good.
There are major exemptions to all these and in the end careful design and implementations seem to count for as much as the fundamental topology.
A bad sounding circuit will still sound bad when using Black Gate capacitors, Vishay Resistors and REL Tinfoil & Teflon Caps.
A good sounding circuit will still sound credible using generic parts (like the Tim De Paravichini EAR 834P), but it will really shine with the right kind of high quality parts.
The best circuit with the best parts is still a bad Phonostage if it hums, buzzes or plays more Radio Yerewan than music.
When comparing the merits of circuitry based on specifications, please remember:
LP has no better than -65dB SNR at 5cm/s signal
LP has over 1% THD at 5cm/s (and usually well over 3% at 25cm/s)
The human hearing has > 30% 2nd HD at around 92dB SPL
Speakers easily approach 0.3% HD at 1W input in the midband (don't ask how much at full power and in the low bass, you do not want to know).
Ciao T
As you can see, you get as many different recommendations as there are people making them.
Over time I probably have build about any possible configurations. Many Phono's can sound good. You need to decide on some ground rules to pick something worth making.
I found I like best circuits with low or no negative loop feedback, where looped feedback is used keeping the feedback factor reasonably constant with frequency is preferable to one that varies widely. Inherent linearity nearly always beats using more feedback.
I like passive LCR based EQ best.
Tubes generally do better than transistors and Fets, subjectively speaking, but some unconventional solid state circuits are also very good.
There are major exemptions to all these and in the end careful design and implementations seem to count for as much as the fundamental topology.
A bad sounding circuit will still sound bad when using Black Gate capacitors, Vishay Resistors and REL Tinfoil & Teflon Caps.
A good sounding circuit will still sound credible using generic parts (like the Tim De Paravichini EAR 834P), but it will really shine with the right kind of high quality parts.
The best circuit with the best parts is still a bad Phonostage if it hums, buzzes or plays more Radio Yerewan than music.
When comparing the merits of circuitry based on specifications, please remember:
LP has no better than -65dB SNR at 5cm/s signal
LP has over 1% THD at 5cm/s (and usually well over 3% at 25cm/s)
The human hearing has > 30% 2nd HD at around 92dB SPL
Speakers easily approach 0.3% HD at 1W input in the midband (don't ask how much at full power and in the low bass, you do not want to know).
Ciao T
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Hi,
Then you did not use the specified J-Fets and you did not match them as specified. The 'pacific was measured by Erno Borbeley using 2SK170 and found gain at 52dB (a little high for MM and a little low for MC, but usable with both) and found Ein 0.14uV for 30KHz bandwidth.
I have build several 'pacific derivates, they work very well.
Yes, however the resistor noise must be considered with the other impedances in the circuit (Thevenin equivalent) where the capacitors lower the effective noise impedance significantly.
For example MadsK schematics shows around 22K plus coupling cap (say 0.1uF) in parallel to the 2.2M gate leak resistor, so at 30Hz the effective noise impedance is only around 75KOhm and at 1KHz it is under 24KOhm (even lower actually due to the lower impedance of the RIAA network, can't be bothered to calculate it).
Ciao T
Then you did not use the specified J-Fets and you did not match them as specified. The 'pacific was measured by Erno Borbeley using 2SK170 and found gain at 52dB (a little high for MM and a little low for MC, but usable with both) and found Ein 0.14uV for 30KHz bandwidth.
I have build several 'pacific derivates, they work very well.
Yes, however the resistor noise must be considered with the other impedances in the circuit (Thevenin equivalent) where the capacitors lower the effective noise impedance significantly.
For example MadsK schematics shows around 22K plus coupling cap (say 0.1uF) in parallel to the 2.2M gate leak resistor, so at 30Hz the effective noise impedance is only around 75KOhm and at 1KHz it is under 24KOhm (even lower actually due to the lower impedance of the RIAA network, can't be bothered to calculate it).
Ciao T
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Witch design do you use Thorsten.
After the problems with my jfet design I cam to the conclusion I have to search for matched transistors. I simulation simetrix it showed nice.
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Hi,
No witches or voodoo involved. My old Vinyl setup is in storage, phono for that is LCR Equalised using E810F/7788 and D3a/7721 tubes, vaguely derived from WWII era german microphone preamplifiers.
Erno Borbeley used to sell them, but he closed up shop.
You could buy the 2SK389GR or the current 2nd source equivalent LSK389A to get good matching between the channels. I did that in some of the 'pacific builds.
Or just buy loads of 2SK170GR match and use them. Do not buy of e-bay unless you know how to spot fakes, there are quite a few out there.
Ciao T
No witches or voodoo involved. My old Vinyl setup is in storage, phono for that is LCR Equalised using E810F/7788 and D3a/7721 tubes, vaguely derived from WWII era german microphone preamplifiers.
Erno Borbeley used to sell them, but he closed up shop.
You could buy the 2SK389GR or the current 2nd source equivalent LSK389A to get good matching between the channels. I did that in some of the 'pacific builds.
Or just buy loads of 2SK170GR match and use them. Do not buy of e-bay unless you know how to spot fakes, there are quite a few out there.
Ciao T
Hi,
I think it was Scott Wurcer or Bob Cordell who mentioned the BF862 (made by NXP) as kind of replacement for the obsolete and expensive Toshiba parts. With similar or even better noise figures and nearly double the gm and still lower capacitance and higher bandwidth the BF862 seems to be a real improvement. I use them in Line Input stages and cascoded JFET output stages and the results were very pleasing.
jauu
Calvin
I think it was Scott Wurcer or Bob Cordell who mentioned the BF862 (made by NXP) as kind of replacement for the obsolete and expensive Toshiba parts. With similar or even better noise figures and nearly double the gm and still lower capacitance and higher bandwidth the BF862 seems to be a real improvement. I use them in Line Input stages and cascoded JFET output stages and the results were very pleasing.
jauu
Calvin
Maybe i didn't explain well what i did. In a 3-stage split riaa using high impedance correction network and separate super regulators for each stage i replaced the input opamp (OPA637/827) with an INA103 set for equal gain. The only compromise was the lowish PS voltage of +-16v set for opamp compatibility. So practically all important conditions were set the same.
I do not claim that the 103 is rubbish or unlistenable; it just doesn't compare all that well to modern opamps in a direct shootout. And i really like what it offers in terms of easily and widely variable gain and extremely low noise and for many this is probably enough.
One thing i didn't try was bypassing the internal opamps and just using the input stage.
Hi Helmuth
Nice to see you are interested in phono stages.
Your pacific style Riaa has a very low PSRR and is greatly affected by the psu performance.
It is very easy to tune the Riaa overall response just by choosing the correct regulator.
IMO it is very difficult to beat Salas simplistic but it must be powered by the shunts and layout and component choice is critical.
Hi Ricardo,
The beauty of salas design is minimal components in the driver-stage, The quality of a 2sk170 is probably the best choice and I have to second your statement that then the chosen filter components will be the mayor influence on the output of this phone stage.
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Yes, the schematic is so simple it does respond beautifully to any modification you perform in the Riaa filter as well as in the shunt output impedance.
It took me a while to get there but now I have a really world class sounding riaa.
It took me a while to get there but now I have a really world class sounding riaa.
Thanks Ricardo I did read it wrong I thought you had made a riaa circuit also in the shunt regulator.😀
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