line amp

[CBS240]

Hi

I solved a problem for my dad today. His TV line out signal is too small for the stereo amp. It will come through, but you have to turn it up almost all the way. I shopped at a couple of stores for a small line amp with Av of 2-8. Couldn’t find what I was looking for, must be that it was too simple. So on that note, it was just easier to build one… simply a duel op-amp IC, with an Av of 6.2 per side. The PS is a small 9VAC transfo scraped from an old cheap clock radio, with a fairly simple regulator. No Zeners!! There is no hum even with ½ V ripple. (220uF instead of 1mF) The only real drawback is that certain j-fets must be measured for the correct Vgs. The Vgs of the 5461(http://www.fairchildsemi.com/ds/MM/MMBF5461.pdf) is larger than the j201(http://www.fairchildsemi.com/ds/MM/MMBFJ201.pdf), they are not complements. Anyway, since I slapped the circuit together this afternoon and it works pretty good, thought someone might be interested. Resistor values are 1st digit, 2nd digit, multiplier.......

100=10 Ohms
101=100 Ohms
102=1K

ect.

Merry Christmas

[CBS240]

Opps Sorry, small error as pertaining to voltage references.

[pfloydphan]

yeah, i use my vcr for a tuner and when i output the audio to my A/V receiver sometimes it seems unusually low. i have to sometimes turn it up to -35db for comfortable listening....well maybe i'm just starting to lose my hearing already :P

[lineup]

Originally posted by CBS240

I solved a problem for my dad today.
------
Anyway, since I slapped the circuit together this afternoon and it works pretty good, thought someone might be interested.

Merry Christmas

Thanks CBS240.
Might be useful some time.
So I download your circuit and save it.

To THINK of my father and fix some thing for HIM
can be the perfect christmas gift
I think he likes it.


Christmas
lineup

[AndrewT]

Hi,
you used letter multiplier for caps and currents.
Why be inconsistent and change the resistor multiplier? Most unconventional.

I can't be bothered converting, so no comment.

[CBS240]

Originally posted by AndrewT
Hi,
Most unconventional.

I can't be bothered converting, so no comment.

Pardon the confusion, this simple sketch also doesn't show that signal GND and PS GND are separate in actual construction. Of course an audio guru such as you would know that.