No, just on the input and output terminals. Defenitly NOT in place of the caps. It's hard to explain to people who obviously can't read a schematic so I tried to say it in the best understandabel way so Noone could do it wrong or has to understand the schematics. If you solder a resistor with one leg on the center pin of the rca connector and the other leg on the outer mass ring of the rca connector then you are fine. This has to be done to all four of them. On the INPUT TERMINAL you can use 300k to 1mOhm, ON THE OUTPUT TERMINALS you can use about 100kohm. SOLDER THEM ON DIRECTLY ON THE TERMINAL NOT, NEVER EVER ACROSS OR IN PLACE OF THE CAPACITORS !!!!!!!!!!!!
It's just a bleeding resistor from the capacitor to ground so it can charge up and does not have to charge up instantly via your amp input in case you connect it when the unit is allready on, that can cause instant death of your poweramp or cd player. In other words, never ever plug it in while it's on. It happened to me, luckily with a cheap replacable lm3875 chip but still, almost cost me my speakers as well. THIS THING IS DANGEROUS WITHOUT BLEEDING RESISTORS AND DOES NOT MEET SAFETY REGULATIONS, period. Excuse me for shouting
It's just a bleeding resistor from the capacitor to ground so it can charge up and does not have to charge up instantly via your amp input in case you connect it when the unit is allready on, that can cause instant death of your poweramp or cd player. In other words, never ever plug it in while it's on. It happened to me, luckily with a cheap replacable lm3875 chip but still, almost cost me my speakers as well. THIS THING IS DANGEROUS WITHOUT BLEEDING RESISTORS AND DOES NOT MEET SAFETY REGULATIONS, period. Excuse me for shouting
O.K. try again. Here is a schematic of the Yaqin. I cannot make it any simpler than this.
If you can read a schematic you'll see that there is no reference to ground on the input and output capacitors. This reference is made by the cd player on the input side and the amplifier on the output side. What happens if the Tube buffer is on but nothing is connected. A voltage is build up on the cap but it does not get charged becasue it floating. When you connect your power amp it instantly charges up but that also means that for a split second there is about 70 volts across the output terminal. This happens only very short but if you happens to have a DC coupled power amp or a power amp with very low voltage input capacitors even a split second of 70 volts is enough to kill it instantly. Same on the input side. The four resistors simply prevent this from happening and that's why THEY ABSOLUTELY HAVE TO BE THERE TO MEET UP WITH EVERY INTERNATIONAL SAFETY REGULATION. The Chinese don't read safety regulations, when they can safe money on four resistors they will leave out six of them.
If you can read a schematic you'll see that there is no reference to ground on the input and output capacitors. This reference is made by the cd player on the input side and the amplifier on the output side. What happens if the Tube buffer is on but nothing is connected. A voltage is build up on the cap but it does not get charged becasue it floating. When you connect your power amp it instantly charges up but that also means that for a split second there is about 70 volts across the output terminal. This happens only very short but if you happens to have a DC coupled power amp or a power amp with very low voltage input capacitors even a split second of 70 volts is enough to kill it instantly. Same on the input side. The four resistors simply prevent this from happening and that's why THEY ABSOLUTELY HAVE TO BE THERE TO MEET UP WITH EVERY INTERNATIONAL SAFETY REGULATION. The Chinese don't read safety regulations, when they can safe money on four resistors they will leave out six of them.
Attachments
O.K. here is my very last effort make this understandable. It is sooooooooooo simple really. Tiring your shoelaces is rocket sience compared to this. This pictures says it all, no more explination.
You can also solder the resistors directly to the pcb but that involves schematic reading and pcb trace following for the more experienced people so pleace don't if you don't know what you are doing.
You can also solder the resistors directly to the pcb but that involves schematic reading and pcb trace following for the more experienced people so pleace don't if you don't know what you are doing.
Attachments
Sjef, ever thought of leaving this device out of the chain ? It seems just as superfluous as a MF X-10 and it lacks basic components thus being a danger for your set. It is a looker and it has tubes, that must be the reason it is popular.
Bleeder resistors combined with a muting circuit are mandatory in devices like this. I would never take the risk of connecting a valuable device to this thing in its original state.
Bleeder resistors combined with a muting circuit are mandatory in devices like this. I would never take the risk of connecting a valuable device to this thing in its original state.
Last edited:
Tazzo, no thanks, just trying to save your ***.
Hi Jean-Paul, I'm actually not using this device in my chain, I just got one to play around with. I bought in in a time long ago when I was fooling around with Tripath amps in a hope to cure some of the Tripath's cold artificial sound but it didn't cure nothing at all.
I have changed all the caps to Wima FKP-1 I had lying around and 4 out of 4 people could not hear even the slightest difference with this thing in or out of the chain. (only tested with the Tripath amps) With the original cheap x-caps the difference was also very very small. (pleas, don't go chasing Wima FKP-1, they are nothing special and most people might not like them because with these in the unit does nothing, zip, nada, njente at all for your sound)
And, yes I would NEVER EVER use this thing in it's original state, It's a time bomb but it can be cured for $0,50
Good news is that the buffer is apparantly pretty transparant, considering the build quality and looking at the schematics that's highly surprising. It would work o.k. as a buffer for a volume pot so I was planning on modifying it with a volume control, put a usb powered dac in it and use it as a usb preamp in my summer house. For the rest it's of no use at all. In practice, I think it just ends up in the closet for the next couple of years.
Hi Jean-Paul, I'm actually not using this device in my chain, I just got one to play around with. I bought in in a time long ago when I was fooling around with Tripath amps in a hope to cure some of the Tripath's cold artificial sound but it didn't cure nothing at all.
I have changed all the caps to Wima FKP-1 I had lying around and 4 out of 4 people could not hear even the slightest difference with this thing in or out of the chain. (only tested with the Tripath amps) With the original cheap x-caps the difference was also very very small. (pleas, don't go chasing Wima FKP-1, they are nothing special and most people might not like them because with these in the unit does nothing, zip, nada, njente at all for your sound)
And, yes I would NEVER EVER use this thing in it's original state, It's a time bomb but it can be cured for $0,50
Good news is that the buffer is apparantly pretty transparant, considering the build quality and looking at the schematics that's highly surprising. It would work o.k. as a buffer for a volume pot so I was planning on modifying it with a volume control, put a usb powered dac in it and use it as a usb preamp in my summer house. For the rest it's of no use at all. In practice, I think it just ends up in the closet for the next couple of years.
I tried the resisters, the RCA wiring was also in place of the solder points. I attached the resisters, but got no sound through. Had to take them back off again.
Had this unit for nearly 2 yrs with no problems nor read anyone else having any. Could it be just that your power amp chip was about to blow anyway? I use an integrated Yamaha A-S500 btw.
Had this unit for nearly 2 yrs with no problems nor read anyone else having any. Could it be just that your power amp chip was about to blow anyway? I use an integrated Yamaha A-S500 btw.
I guess this is a bad joke ? Wima FKP-1 and FKP-2 are among the best capacitors you can get for money. And by best I mean best, in contrary to overpriced stuff like Audyn and other exotic brands.
Or do you think that these are not worth putting in projects because they are not expensive ? The only downside I see is that they have short leads which makes them suitable for PCBs but for point to point wireing you have to solder some extensions
Oh, I use the FKP-1 a lot because I have a lot of them They are good capacitors but nothing miracle, special, hyper highend or what not, just a decent capacitor that does nothing wrong. That's the reason why many people might not like them in this device because they use this device to add this so called "tube warmth". That something this simple cathode follower doesn't do so they ar actually listening to the cap colouration, wich in some cases might cure some nasty sound. Like I said befoe, this is a nice transparant buffer for a passive preamp, as long as your power amp is easy to drive. That's the only real use for it I can think of.
And yes, it is possible that you use this device for a 100 years and nothing goes wrong. But in the case you happen to have a DC coupled power amp and you plug in the device while it is on, then you are in big trouble. If you are absolutely a 10000 % sure you will never ever do that then there is no problem at all. I repeat, it only is a problem when you plug in in while it is on, or was on a short moment ago and did not have enough time to discharge. In this situtaion I measured around 70V on the output for a very short period of time, but long enough to be harmfull. This is cured with a simple resistor.
What kind of value of resistor did you use ? How did you solder it ?
And yes, it is possible that you use this device for a 100 years and nothing goes wrong. But in the case you happen to have a DC coupled power amp and you plug in the device while it is on, then you are in big trouble. If you are absolutely a 10000 % sure you will never ever do that then there is no problem at all. I repeat, it only is a problem when you plug in in while it is on, or was on a short moment ago and did not have enough time to discharge. In this situtaion I measured around 70V on the output for a very short period of time, but long enough to be harmfull. This is cured with a simple resistor.
What kind of value of resistor did you use ? How did you solder it ?
Hello, I own a Yaqin tube buffer sd-cd3. I am wondering about the bleeder resistors mod. And bypass caps mod.
Some People use 470k on the inputs and 100k on the outputs. I have some spare 500k and 90k. You think I can use those instead..? Respectively..
Also for PSU bypass caps, most people use 1uf...I have some Rifa 0.47uf 250v caps. You think I can use those as bypass caps for the PSU
Any help would be appreciated.
Thanx
Max.
Some People use 470k on the inputs and 100k on the outputs. I have some spare 500k and 90k. You think I can use those instead..? Respectively..
Also for PSU bypass caps, most people use 1uf...I have some Rifa 0.47uf 250v caps. You think I can use those as bypass caps for the PSU
Any help would be appreciated.
Thanx
Max.