| lykkedk |
Hi again, I wrote this new thread, cause I think someone might have misunderstod my quistion.
I'am just building this Balanced Line Stage, which I plan to use, for preamplifieng, lines from my CD, Computer, DVD etc...
None of theese, seem to be balanced equipment.
My CD is a SONY X55ES, which I will connect through GoldPHONO'S (RCA), the output will be golded too. The rest of the input RCA's will be cheaper one's.
The output should go to my Leach-amp which I think have an inputimpedance around 20kohm. The Leach amp is with one powersupply, and two mono-block's, with one RCA for LEFT input, and one RCA for RIGHT input.
I made a little change to the PCB for the line stage, so I could use 1,5k/11w ohm resistor instead of the two 750ohm/3w one's
Actually I have used a lot of time making the PCB (Handmade), and I allready soldert most of the component's to it, hoping to use it unbalanced without making any changes on the PCB, and component's used.
I was planing to use a stereopot for P3/P4, for volume control.
This is, what I really wanna know, so please HELP...
Howto use it unbalanced, maybe with some grounding at -IN, and -out, really i do not know howto do this...
What about R15, I use 124ohm. is this right, when not using P1, and P2.
Well I had not yet bought any pot's, so I am open to any suggestion's. |
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| Henrik |
lykkedk| quote: | | Howto use it unbalanced, maybe with some grounding at -IN, and -out, really i do not know howto do this... |
You simply short -In to ground with wire.
I wouldn´t short the unused output to ground, no need for that.
| quote: | | What about R15, I use 124ohm. is this right, when not using P1, and P2. |
R15= 124 Ohm is ok!
Lower the gain as much as possible by increasing P5, this way You get the lowest distortion. |
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| lykkedk |
[Then I only have to short -IN, and use GND / +OUT, to the female RCA (Phono) ?
What about C1 R9 R11, I dont have to use at all ?? , or could I just leaveout C1, cause I allready soldert the R9 and R11, into the PCB. The reason I ask about leaveout C1 is, that they're pretty big. (Would leave me more space for only one of them) javascript:smilie(':bigeyes:')
I wasent thinking, of using P5, I just want to make a short here, that's why I quistion about
R15, because I have seen some schematics, where 430ohms where used in unbalanced operation. |
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| Henrik |
| quote: | | [Then I only have to short -IN, and use GND / +OUT, to the female RCA (Phono) ? |
Yes.| quote: | | What about C1 R9 R11, I dont have to use at all ?? , or could I just leaveout C1, cause I allready soldert the R9 and R11, into the PCB. The reason I ask about leaveout C1 is, that they're pretty big. |
Those You don´t need, unless You some day wants balanced operation.| quote: | | I wasent thinking, of using P5, I just want to make a short here, that's why I quistion about |
Try some diffrent values, I think You will need about 350 Ohm for R15, but that depends. |
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| 2Bak |
| quote: | | was planing to use a stereopot for P3/P4, for volume control. |
If running unbalanced only you will not need a pot at P3 but at P4 only (e.i. a stereo-pot for both channels). However if you plan to use - out later (balanced out), then think twice before you buy the pot for P3, cause a stereopot cannot be used as pot for both P3 and P4. Only a 4-channel pot or attenuator can be used for that (balanced). |
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| lykkedk |
| Yes sure, P4 only |
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