Hey Guys
The hum is this time TOTALLY gone!
We reviewed the Yaqin this morning with a friend, split the input RCA ground and he also has had a mini "69" circuit (diodes, cap and R) to clean the ground signal going from the pcb to the chassis
Now with new Russian oil paper caps and chassis raised on spikes (due to the caps size) this little Yaqin sounds incredible!
Next step: Sylvania NOS tubes on the way
The hum is this time TOTALLY gone!
We reviewed the Yaqin this morning with a friend, split the input RCA ground and he also has had a mini "69" circuit (diodes, cap and R) to clean the ground signal going from the pcb to the chassis
Now with new Russian oil paper caps and chassis raised on spikes (due to the caps size) this little Yaqin sounds incredible!
Next step: Sylvania NOS tubes on the way
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HI SDIESEL77
Glad you have managed to sort the problem and it sounds as if you have managed to improve on it as well.
Could you post details (circiut diagram) of the 'mini 69 circuit' so that I can try it on mine.
What caps did you actually change? (Russian paper in oil) and I might give that a go as well.
Many thanks
Glad you have managed to sort the problem and it sounds as if you have managed to improve on it as well.
Could you post details (circiut diagram) of the 'mini 69 circuit' so that I can try it on mine.
What caps did you actually change? (Russian paper in oil) and I might give that a go as well.
Many thanks
Hey Will,
The caps changed were the C4 C7 C11 C12 (1uf 275v) in the schematic by Russian Oil paper ones (1uf 600v but if you find lower voltage it's fine too and will take less space).
For the grounding circuit (Big Thanks to my friend Fran for his genius idea): You'll need 2 x 1n4007 diodes, a 10-30R >5W resistor and a 0.001-0.02uF 400V cap. Quality or type of any of these is not important.
Diodes: QL79L, QL78K QL77J or QL79L will do fine
Resistor: L6R8, L8R2, L10R, L15R or L22R
Cap: any cheap ceramic cap low value 0.001-0.02uF ~400V or so
The caps changed were the C4 C7 C11 C12 (1uf 275v) in the schematic by Russian Oil paper ones (1uf 600v but if you find lower voltage it's fine too and will take less space).
For the grounding circuit (Big Thanks to my friend Fran for his genius idea
): You'll need 2 x 1n4007 diodes, a 10-30R >5W resistor and a 0.001-0.02uF 400V cap. Quality or type of any of these is not important.Diodes: QL79L, QL78K QL77J or QL79L will do fine
Resistor: L6R8, L8R2, L10R, L15R or L22R
Cap: any cheap ceramic cap low value 0.001-0.02uF ~400V or so
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Hi SDIESEL
Just to check. With the '69' circuit you disconnect the earths on the board. Solder the '69' to the board and then solder the earths to the other end of the '69'. Is that correct?
I have tried it this way - did'nt cure the hum completely but quietened it down quite a bit. The problem I guess for me is the SUT still looking to cure this.
Many thanks for sharing.
Regards
Just to check. With the '69' circuit you disconnect the earths on the board. Solder the '69' to the board and then solder the earths to the other end of the '69'. Is that correct?
I have tried it this way - did'nt cure the hum completely but quietened it down quite a bit. The problem I guess for me is the SUT still looking to cure this.
Many thanks for sharing.
Regards
Hey,
Actually, you don't disconnect both earth (chassis and TT input), you only disconnect the cable going from the PCB to the chassis.
Then as you said, you solder the "69" to the board and the other end to the cable that is screwed to the chassis.
This really cured completely the hum for me, then if it's still there for you, I'll indeed look at your SUT.
What do you use the SUT for ?
Actually, you don't disconnect both earth (chassis and TT input), you only disconnect the cable going from the PCB to the chassis.
Then as you said, you solder the "69" to the board and the other end to the cable that is screwed to the chassis.
This really cured completely the hum for me, then if it's still there for you, I'll indeed look at your SUT.
What do you use the SUT for ?
Hi SDIESEL
I use the SUT for a MC cartridge feeding into the Yaqin. I reconnected the circuit as you suggeted with only the chasis earth connected to the '69', still got a bit of a hum but not that much.
In all the messing about the blue LEDs have stopped working. Not a problem, I'll sort it ought if I ever get round to replacing the caps. However it may be just fancy but I think it sounds better without them working. As you know there is a socket on the other side of the board which should make connecting them and diconnecting them really easy. I remember reading somewhere that LEDs introduce noise. So for now I just use it without.
The SUT thing and ground loops seems to be a bit of a mystery, trial and error it would appear. But at present it is running really well. Thanks for your help.
Regards
I use the SUT for a MC cartridge feeding into the Yaqin. I reconnected the circuit as you suggeted with only the chasis earth connected to the '69', still got a bit of a hum but not that much.
In all the messing about the blue LEDs have stopped working. Not a problem, I'll sort it ought if I ever get round to replacing the caps. However it may be just fancy but I think it sounds better without them working. As you know there is a socket on the other side of the board which should make connecting them and diconnecting them really easy. I remember reading somewhere that LEDs introduce noise. So for now I just use it without.
The SUT thing and ground loops seems to be a bit of a mystery, trial and error it would appear. But at present it is running really well. Thanks for your help.
Regards
Hey Will,
You can look on eBay for any NOS oil paper ones 1uf and minimum 275v
I found the following ones, however they're 250v (instead of 275v), it'll be good to check what's the actual voltage going through the original ones in place in the Yaqin.
ex:
K75-10 V Paper In Oil PIO Capacitor 1uF 250V 10%, Lot of 20 | eBay
You can look on eBay for any NOS oil paper ones 1uf and minimum 275v
I found the following ones, however they're 250v (instead of 275v), it'll be good to check what's the actual voltage going through the original ones in place in the Yaqin.
ex:
K75-10 V Paper In Oil PIO Capacitor 1uF 250V 10%, Lot of 20 | eBay
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is not necessary all this...the datasheet of the pre is my distribution, because i lost a lot of time on this pre.
you need replace every component with better quality, replace 12ax7 with 6n2p (change voltage) remove ground on chassis, or remove ground from input, you can buy a power cord without ground (same marantz hifi)
Available
bye!
you need replace every component with better quality, replace 12ax7 with 6n2p (change voltage) remove ground on chassis, or remove ground from input, you can buy a power cord without ground (same marantz hifi)
Available
bye!
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I wouldn't advise to do that AT ALL, that's the best way to get electrocuted with DC current !
Super DIY guide
Hi SDIESEL77
I found your guide on the riaa on youtube, just wanted you to know that it´s awesome and easy to follow.
I have modded my own Yaqin MS-22b
with the following;
C4,C7,C11,C12
4 Jantzen audio Superior Z-cap 1.0 uF 800VDC
Quite huge, so have also modified the bottom and extended the bottom with aluminium rods fitted on 9mm plexiglass, looks super cool with the blue glow coming out from underneath
The two capacitors in the front C1, C8
new capacitors - ELNA 220uF 25V SILMIC II RFS Silk Audio Capacitor
And the result
It´s just awesome!!!!
However I still have the original china 12ax7 vacuum tubes attached.
Any recommendations to better ones.
I´m mostly listening to heavy & death metal, so some which can handle the fast changing dynamics.
Also fixed the humming, it´s still there when you crank up the volume to 2/3 when music it´s not on. Is yours completely gone at max volume from main-amp?
Hi SDIESEL77
I found your guide on the riaa on youtube, just wanted you to know that it´s awesome and easy to follow.
I have modded my own Yaqin MS-22b
with the following;
C4,C7,C11,C12
4 Jantzen audio Superior Z-cap 1.0 uF 800VDC
Quite huge, so have also modified the bottom and extended the bottom with aluminium rods fitted on 9mm plexiglass, looks super cool with the blue glow coming out from underneath
The two capacitors in the front C1, C8
new capacitors - ELNA 220uF 25V SILMIC II RFS Silk Audio Capacitor
And the result
It´s just awesome!!!!
However I still have the original china 12ax7 vacuum tubes attached.
Any recommendations to better ones.
I´m mostly listening to heavy & death metal, so some which can handle the fast changing dynamics.
Also fixed the humming, it´s still there when you crank up the volume to 2/3 when music it´s not on. Is yours completely gone at max volume from main-amp?
Humming issue still
I still have quite an issue with humming, have tried different things to get rid of it. Tube rolling doesn´t have any effect on the humming.
Can I update the ground filter somehow to make it more efficient.
I have the 2 diodes as you described. Then I have a 10 ohm resistance and a 0.047 uF 250V cap.
Could it be the capacitor mods installed causing it or should I do something with the ground filter, higher resistance or / and higher value cap
I still have quite an issue with humming, have tried different things to get rid of it. Tube rolling doesn´t have any effect on the humming.
Can I update the ground filter somehow to make it more efficient.
I have the 2 diodes as you described. Then I have a 10 ohm resistance and a 0.047 uF 250V cap.
Could it be the capacitor mods installed causing it or should I do something with the ground filter, higher resistance or / and higher value cap
Hey,
Last week I was also annoyed by a hum and actually a friend of mine found the problem, it wasn't coming from the pre-amp but from another source !
I would advise you to disconnect all other sources (cd player, tuner, ...) and only leave the pre-amp. Run a test and see if the hum is still there.
In my case, it was the Tuner that was creating this RF hum in the pre-amp.
Hmmm I have been exploring since you wrote and the main noise comes actually from the interconnect cable from the turntable to the preamp. Is it possible to insert some kind if noise filter from the turntable to the preamp. How about ferrit core on the interconnects would that help.
Would it also Make a change upgrading the resistance to 20 ohm and a higher uF on the capacitor in the preamps ground filter?
Would it also Make a change upgrading the resistance to 20 ohm and a higher uF on the capacitor in the preamps ground filter?
Hey
Have you checked what I said before: unplugging all other sources ?
Check if the ground cable from your turntable to your pre amp is well connected/soldered.
The hum can also come from the cartridge or the turntable output cable but that's more unlikely.
You could also double check that the 69 ground circuit is correctly connected to the chassis via a screw touching the non anodised chassis part.
Sent from my GT-N7100 using Tapatalk 2
Have you checked what I said before: unplugging all other sources ?
Check if the ground cable from your turntable to your pre amp is well connected/soldered.
The hum can also come from the cartridge or the turntable output cable but that's more unlikely.
You could also double check that the 69 ground circuit is correctly connected to the chassis via a screw touching the non anodised chassis part.
Sent from my GT-N7100 using Tapatalk 2