If the sensitivity of your main amp or the drive in the lows, proves below expectations when directly driving from the phono through a pot, make a 12B4A tube preamp with 6k8 10W anode load, 1k2 cathode resistor bypassed with BGN. B+ 320V. Gain measured=X3.56. Sounds much more grand in everything than JFET line anything and the gain is adequate for modern systems. Just 1 stage triode with low output impedance. Can't get any simpler really. Of course high voltages are for the careful experimenter.
Salas, I read a lot for this topic, Now I have Sumiko blue point EVO III cartridge, I want DIY phono stage matching my cartridge impedance for my system. Could you please help and suggest?
BLUE POINT SPECIAL EVO IIITM
High Output Moving Coil
• Frequency Response: 12 Hz. - 50 kHz.
• Output Voltage: 2.5 mV per channel at 1 kHz.; 5 cm./sec. peak recorded velocity. Output from each channel within 2 dB.
• Channel Separation: Minimum 35 dB at 1 kHz.
• Channel Balance: Within 0.5 dB.
• Optimum Load: 47, 000 ohms resistance in parallel with 250 to picofarads total capacitance.
Cheer!
pajonec
BLUE POINT SPECIAL EVO IIITM
High Output Moving Coil
• Frequency Response: 12 Hz. - 50 kHz.
• Output Voltage: 2.5 mV per channel at 1 kHz.; 5 cm./sec. peak recorded velocity. Output from each channel within 2 dB.
• Channel Separation: Minimum 35 dB at 1 kHz.
• Channel Balance: Within 0.5 dB.
• Optimum Load: 47, 000 ohms resistance in parallel with 250 to picofarads total capacitance.
Cheer!
pajonec
nicoch46 said:
Thank you nicoch46
I like the idea of no caps... Did you hear it ?
Ricardo
PS: Look at the complexity : http://www.youtube.com/watch?v=VZM8iNTZruY&feature=related
BIG improvements ahead !!!
1st - Again following Salas indications, I bought some mogami teflon coax and decided to replace the solid core copper wire used to bypass the 101b MC stage, with a small lenght of the coax.
Inittially I heard "thin" sound, but with more detail. after 12 hour burn in, the bass came alive "full on".
Multi thin stranded OFC wire is better to carry signal than thick solid core I guess. (Must have something to do with superficial conductivity, in thick wires there is a small amout of frequencies that use the outer copper layers while low freq travels inside the wire... I believe this causes some "bracking" to the signal depending on the frequency.)
2nd - Also based on previous readings in this forum, I decided to bypass the 4.7u obbligato Riaa output caps with a russian teflon. For now I am using Teflon K72-6 0,047uF (47nF) and the results are awesome. The teflon caps do not add any signature to the sound (unlike the PIO I used before that give a Big Guitar/Jensen effect). The teflon provide an enourmous increase in detail and bass extension without affecting the main cap sound.
I am now waiting for some 100nF FT-3 to experiment so I will be reporting soon.
Ricardo
1st - Again following Salas indications, I bought some mogami teflon coax and decided to replace the solid core copper wire used to bypass the 101b MC stage, with a small lenght of the coax.
Inittially I heard "thin" sound, but with more detail. after 12 hour burn in, the bass came alive "full on".
Multi thin stranded OFC wire is better to carry signal than thick solid core I guess. (Must have something to do with superficial conductivity, in thick wires there is a small amout of frequencies that use the outer copper layers while low freq travels inside the wire... I believe this causes some "bracking" to the signal depending on the frequency.)
2nd - Also based on previous readings in this forum, I decided to bypass the 4.7u obbligato Riaa output caps with a russian teflon. For now I am using Teflon K72-6 0,047uF (47nF) and the results are awesome. The teflon caps do not add any signature to the sound (unlike the PIO I used before that give a Big Guitar/Jensen effect). The teflon provide an enourmous increase in detail and bass extension without affecting the main cap sound.
I am now waiting for some 100nF FT-3 to experiment so I will be reporting soon.
Ricardo
Today I am etching the pcb for the second shunt. (I revised the initial layout in order to get more space for the mosfets.
It will be a clone of the first one, using exactly the same components, so I expect I will get the same performance and voltage output.
As the TX is quite big, I can not fit a second one, so the shunt will be sharing the same winding.
As I do not have enough parts now, for the rectifier and smoother cap, I will be using only one inittially and will build a second one latter.
Resuming: 1 TX, 1 rectifier bridge, 1 smoothing cap, 2 shunt.
Ricardo
PS: in attach you have the revised pcb.
It will be a clone of the first one, using exactly the same components, so I expect I will get the same performance and voltage output.
As the TX is quite big, I can not fit a second one, so the shunt will be sharing the same winding.
As I do not have enough parts now, for the rectifier and smoother cap, I will be using only one inittially and will build a second one latter.
Resuming: 1 TX, 1 rectifier bridge, 1 smoothing cap, 2 shunt.
Ricardo
PS: in attach you have the revised pcb.
)
Can you explain that better? You want to substitute the standard phono buffer 3rd stage, or you want to use a 2 stage phono plus a cap-less B1? Can you point me to the schematic you are building, so I can check it out with a B1 style tail?
EDIT: You mean that surface mount for DIP8 job I guess. I have listened to a 2 stage phono plus my capacitor-less B1 as a buffer/volume. They work fine together. So your plan is analogous and I see no problem about it.
EDIT: You mean that surface mount for DIP8 job I guess. I have listened to a 2 stage phono plus my capacitor-less B1 as a buffer/volume. They work fine together. So your plan is analogous and I see no problem about it.