ANYONE HELP!!! Helios line input

Hi!

I try to build my "tiny" home studio.I have no money so i didn't buy preamp,good soundcard or something like this.Just i have Behringer UCA-222.Now i need mic preamp and line input.I decided i will build 2Ch Green Pre V1.OK!Preamp is OK! I need a line input now.I want to build just 2Ch line input like 2mic in and 2line in soundcards.I found a circuit!

http://www.groupdiy.com/index.php?topic=31827.0

Well! Can i use this schematic for line input?

If it's true schematic for me,i will use it."I don't need balanced input-output."

Thanks!

Anyone?

yes, you could input a line source, the input impedance is very high. Normally a 1:10 input transformer is used with this circuit (for microphone use).

This circuit, however, is very colored, has some distortion. But can sound very very good.

Hi gemini86,

Thanks for reply.

I will use for record guitar/bass right? (or another line equipment) And if i add 1:10 transformer,i can use mic preamp right? So i will have line and mic input in one box right? Did i understand right? If i understand,i will be really really happy!  :

You are correct.

This is how it would be hooked up to a mic transformer: (see card 1 in schematic)
http://danalexanderaudio.com/OutboardPic/HeliosChannelSchem.jpg
Original circuit:
http://www.vintageking.com/site/files/images/schem_V69-1973-2-Var-1.jpg
(Although I believe it's drawn wrong there.)

Thanks! Thanks! Well! I'm really happy now ;D

Now i want to ask some questions.

1.I can't audio transformer and i have no money to buy from overseas.Can i use power transformer?If i can use,how transformer?

2.I think i can't find MPSA14 transistor.If i can't find this transistor,what can i use?

Thanks again!

1) Well, if you're in a 240/230v country, a 24v transformer will work. (that's about 1:10) Look for a small one.
2) What are you planning to plug this into? If it's a 10K input, you don't even need the output pair, just the original schematic with 3 transistors will work and sound great.

1.Yes i'm in a 220v country.But what can i use? DC or AC ?I think i have to use AC transformer right?
2.I will plug this in to Behringer UCA-222.I don't know what is input empedance.If i build orginal schematic,can i use BC550C and BC560C again?

But i didn't understand orginal schematic.I did orginal schematic like this.Is this true?
http://imageshack.us/f/266/schemv6919732var1.jpg/

1) There's (technically) no such thing as a DC transformer. Just a regular small power transformer will do.
2) The manual for your unit says input impedance is 27K, this will work fine. And yes, you can use BC560/550.
The schematic is right, but the last two transistors are the wrong symbol, they show PNP instead of NPN. They should be drawn like this:

But as drawn, the schematic is right.

Look at the channel schematic I linked, card 1 has different pins, these pins are the same as your schematic. pin 16 goes to the gain setting resistor, this can be a 6 position switch with 6 different resistors like the channel schematic shows.

0V (pin 8) goes to ground.

Well!I understood everything.

Actually i don't want to use switch.I will use setting resistor.But i didn't understand how i add setting resistor.Can you show it?

Thanks!

Hey! I made a circuit with BC560C and BC550C.

Is this true?

http://imageshack.us/f/209/heliosinput.jpg/

I want to use potantiometer.Did i replace it true?And capacitor's polarized is true right?

If you say this schematic is true,i will add mic input.

Thanks!

Hey!!!!!!!!

Can you please just attach the image here instead of hosting it. Image shack makes it tiny and I can't read it. The pot may not work the way you want it to. Also if you ever need unity gain (gain of 0), you need a switch to lift the pot from ground completely. A switch will cost maybe a couple dollars more than a pot.

gemini86 said:

Can you please just attach the image here instead of hosting it. Image shack makes it tiny and I can't read it. The pot may not work the way you want it to. Also if you ever need unity gain (gain of 0), you need a switch to lift the pot from ground completely. A switch will cost maybe a couple dollars more than a pot.

Click to expand...

I know a switch is not expensive but i can't find it in here.So i have to use pot. :-\ How can i add pot?

Where are you located that you cannot find a switch?

gemini86 said:

Where are you located that you cannot find a switch?

Click to expand...

In Turkey..

By the way my schematic is correct right? I just replaced transistors.

Schematic looks good, try a 25k rev log pot (if you can find one) with a 110ohm between that and ground.

gemini86 said:

Schematic looks good, try a 25k rev log pot (if you can find one) with a 110ohm between that and ground.

Click to expand...

Thanks! I will do what you say.And if you say "everything is OK", i will start to build!

very nice sounding pre, u wont regret building it...

leadbreath said:

very nice sounding pre, u wont regret building it...

Click to expand...

+1000...

Building 6 channels for someone at the moment. Will be building a couple for myself as well.