Dear friends!
Many members are encouraged me to use the phono boards for D3A.
I was make it for my system, it is simple and the sounds is very good, i lke it You can see this Phono in the image and design in this link:Hi-end phono preamplifier
Many members are encouraged me to use the phono boards for D3A.
I was make it for my system, it is simple and the sounds is very good, i lke it You can see this Phono in the image and design in this link:Hi-end phono preamplifier
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Yes, thank you, it was in my bucket list. I've got the tubes and all the good parts collected. Do you also provide the PCB for this project? I was just about to design the PCB.
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I have some my friends interested to build this easy and good phono preamplifier so if we will arrive to 50 persons the price should be only 50$ each including shipping cost.
This project use D3a easy to find on Ebay germany shop at 10-12$ each.
The sound depend by the passive components used.
This project use D3a easy to find on Ebay germany shop at 10-12$ each.
The sound depend by the passive components used.
I am thinking to use a Salas shunt on high voltage power supply as alternative to the Virtual Battery.
This is a must. I wouldn't use anything else in low level circuits and power amp driving sections. In comparison series regulators really suck.
The 50$ should include the pcb of the preampl., the pcb of the power supply and the shipping cost.
Just a small question did you put some grid stoppers on tubes, since I do not see them in schematics, and D3a are known to oscilate easy?
In these last 2 years I have design many circuit with the D3a and I never seen problem of oscillation without grid stop resistor.
Other tubes give me these problems like the 5842 and 6C45.
I consider this tube perfect for these points:
1) only one brand so always the same neutral good sound
2) low distortion for large swing (see measurement on my PF2007 amp.)
3) no oscillation
4) no microphonic
5) high gain about 70
6) low internal resistance in triode connection near 2Kohm
7) low cost about 10-12$
8) easy to find on german Ebay shop
Other tubes give me these problems like the 5842 and 6C45.
I consider this tube perfect for these points:
1) only one brand so always the same neutral good sound
2) low distortion for large swing (see measurement on my PF2007 amp.)
3) no oscillation
4) no microphonic
5) high gain about 70
6) low internal resistance in triode connection near 2Kohm
7) low cost about 10-12$
8) easy to find on german Ebay shop
OK I would prefer it be there but if you have experience otherwise I am ok with it. I know the tube, have some of them on my small stock.
I know you simulated it and measured it but could not never understand how you found 16pF at the input of the second stage is so low. From the datasheet I see we have like 2pF and with miller and gain of 70 it should be more like 140pF. Would you please explain where I am wrong?
Pred
PS
Price at German ebayers is much higer now. They found people in HIFI like them so it is now more like 25-35...
PPS
I still wanna PCBs 🙂
I know you simulated it and measured it but could not never understand how you found 16pF at the input of the second stage is so low. From the datasheet I see we have like 2pF and with miller and gain of 70 it should be more like 140pF. Would you please explain where I am wrong?
Pred
PS
Price at German ebayers is much higer now. They found people in HIFI like them so it is now more like 25-35...
PPS
I still wanna PCBs 🙂
Hi,
I am also interested if it is suitable, how much gain will it have compared to my CA 640p? The 640 specification is Gain @ 1kHz = 55dB,Nominal output 300mV,Sensitivity for 0.5mV nominal output.
The this is enough for my 0.5mV at33prg cart.
Thanks
Ian
I am also interested if it is suitable, how much gain will it have compared to my CA 640p? The 640 specification is Gain @ 1kHz = 55dB,Nominal output 300mV,Sensitivity for 0.5mV nominal output.
The this is enough for my 0.5mV at33prg cart.
Thanks
Ian
Ian,
This phono preampl. is good for any type of MM and for MC high output cartridge.
In a measurement I have on output 1.24Vrms with 3mV input and this mean 52.3dB.
Is you have low output MC cartridge it is necessary an input step/up transformer.
This phono preampl. is good for any type of MM and for MC high output cartridge.
In a measurement I have on output 1.24Vrms with 3mV input and this mean 52.3dB.
Is you have low output MC cartridge it is necessary an input step/up transformer.
