Is there a screen around the cartridge signal wiring?
That screen should be completely separate from the audio channels. It should be connected to chassis at both ends.
If there are any other metal parts that are not "Earthed", then connect them to the "Earth" tab/bolt next to the Phono input sockets.
That screen should be completely separate from the audio channels. It should be connected to chassis at both ends.
If there are any other metal parts that are not "Earthed", then connect them to the "Earth" tab/bolt next to the Phono input sockets.
A clear indication for mechanical motor/platter/bearing rumble. In such a case, grounding anything doesn't make a difference.
Jan
Mechanical rumble should be influenced by rotation speed, earlier 120...130Hz was mentioned as about the frequency of the noise.
The platter and the arm is on a separate steal beam with spring suspension,I think (was a while since I had it open)the motor i screwed to the wodden chassie free from the steal beam wich is connected with a whire to the bolt at the back of the TT,I shall connect it to the bolt on paradise.
Well that deppends on wich LP i playing,Joe Satriani Flying in a blue dream sounds just fine.
That didn´t make any difference.....
And I have oil in the bearing,could there be to little oil?
And what I can file there is no bearing loosenness.
Put a screwdriver in your ear (the plastic/wooden end) and place the other end (the 'driver' end) on the turntable and listen 🙂 mechanical noise should show itself.
Yes I used to listen to the car engine with a screwdriver..
It´s hard to tell but I think I hear a "little" from the TT motor with the scredriver on the wodden chassie,It´s strange,that I get a sound in the speakers, because the only thing "between" the platter and the motor is the strap.Everything else is floating.
It´s hard to tell but I think I hear a "little" from the TT motor with the scredriver on the wodden chassie,It´s strange,that I get a sound in the speakers, because the only thing "between" the platter and the motor is the strap.Everything else is floating.
At last, I decided to build Paradise phono stage. I made PCB myself, matched transistor and RIAA capacitors. I have enough 2SK 170 , but I wish to know Idss of Q97 and QQ98 and if it they should be matched. Same for Q 99. Is input bias current constant after trimming?Is 430hfe optimum for input stage?
I decided not to use integral shunt regulators, but Jung-Didden SR or Borbely series or shunt reg.
I have powered one channel of Paradise , fair amount of output fluctuation +/-80mV with 10k on the input , covered input stage , input sits at 0mV , pin 6 ~1.3V .
I'm not sure if Calvins are pulling as much current as required , I have 16mA going through R6&R11 , power supplies push 150mA per rail , all voltages within the range , where to look , shall I increase Calvins current ?
Many thanks
I'm not sure if Calvins are pulling as much current as required , I have 16mA going through R6&R11 , power supplies push 150mA per rail , all voltages within the range , where to look , shall I increase Calvins current ?
Many thanks
These buffers are driving me crazy , fired up the other one and all LEDs apart from the bank under heatsink are not lightning , high and random voltage between in and out of the buffer , very high current through the buffer .
I swapped all transistors and now I have ~50mA through 2R2 , LEDs lightning up , not adjustable in-out ~30mV .
Both Paradise boards behave in the same way depending which Calvin connected , drawing either 19mA or 50mA respectively .
Do I need to play with R5 and R6 to set the current ?
Anyone?
I swapped all transistors and now I have ~50mA through 2R2 , LEDs lightning up , not adjustable in-out ~30mV .
Both Paradise boards behave in the same way depending which Calvin connected , drawing either 19mA or 50mA respectively .
Do I need to play with R5 and R6 to set the current ?
Anyone?
I replaced R6 and R11 on high current board and it pulls now ~30mA with 25mA going through 2SA1381 but trimpot adjustment takes me only down to 30mV .
I havent matched PF5102 , would it be that , do I need to match j107 as well?
I havent matched PF5102 , would it be that , do I need to match j107 as well?
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Kamis, Q97 and Q98, it really doesn't matter. Match them if you like, you won't hear or measure a difference.
Q99 c 8 mA, matched against other channel.
Input bias really needs to be trimmed with loading resistor and cartridge attached. It doesn't drift once set.
Q99 c 8 mA, matched against other channel.
Input bias really needs to be trimmed with loading resistor and cartridge attached. It doesn't drift once set.
R 5 and R7 surely?
Slav, the input transistors and their cascodes need matching. It's easier to set the Calvins up separately, with the 100k R15 fitted. Once you have them dialled remove R15 and fit to the Paradise.
IDSS 8-8.5mA for the input transistor. Match them for
You'll not get steady output from the Paradise until you have about 100 hours on the main boards and they are thermally stable, ie cased up. The large lytics take a long time to form and settle with no leakage.
Slav, the input transistors and their cascodes need matching. It's easier to set the Calvins up separately, with the 100k R15 fitted. Once you have them dialled remove R15 and fit to the Paradise.
IDSS 8-8.5mA for the input transistor. Match them for
You'll not get steady output from the Paradise until you have about 100 hours on the main boards and they are thermally stable, ie cased up. The large lytics take a long time to form and settle with no leakage.
I increased R6&R11 as they define how much current is flowing through the whole circuit , R5&R7 define how current splits between jfets and bipolar ,
I shall fiddle bit more later
Any helpful circuit to match input transistors and cascodes , Atlas DCA55 is bit useless in this case?
I shall fiddle bit more later
Any helpful circuit to match input transistors and cascodes , Atlas DCA55 is bit useless in this case?
What should I aim for when adjusting Calvins , total current of 30mA with 4-5mA through cascode?
What baffles me no adjustment below 30mV
What baffles me no adjustment below 30mV
Do you mean disconnect in/out from the board and plug R15/100k?
I've tried to lower R5 and R7 , went down to 2R2 same as R6 R11 on the working/adjustable buffer and overal current is 25.5mA with 4.5mA going to jfets , don't seem to be right .
I have ordered some matched PF5102 , question remains what's best way to match 2SA1381 and J107?
Just a quick question regarding transistor matching for Calvin buffer ,
should they be matched for Idss @Vgs=0V and have similar threshold voltage - Vth ?
should they be matched for Idss @Vgs=0V and have similar threshold voltage - Vth ?