bgpaladin
New Head-Fier
- Joined
- Oct 6, 2010
- Posts
- 6
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Hi,
I bought a JDSLabs headphone amp awhile ago and thought it was great! I got interested and tried to build a CMOY amp according to Tangent's tutorial. Using an OPA2227PA (from the JDSLabs amp) the sound is OK, although not quite as good. However, when I try an NE5532, TL072 or JRC4560D I have terrible problems.
When I check the power supply with no op-amp plugged in, my 9V battery splits accurately into +4.5v and -4.5v, as expected.
However, whenever I plug in one of the "inferior" op-amps, I get big voltage swings and soft and badly distorted sound.
eg.
No amp 9.4v +4.7v -v.7v
OPA2227 9.39v +3.39b -5.93v sounds OK
NE5532 9.42v +7.44v -1.50v medium volume, distorted
when I put one thumb on the underside covering soldered pins 1-4 and the other
thumb covering pins 5-8 the volume increases and the sound improves a lot.
Checking the voltages again, while touching the connections, the voltages are
closer, but still no where near equal.
I plugged this op-amp into the JDSLabs and got good sound and equal voltages:
9.08v +4.55v -4.53v
JRC4560D 9.40v +0.88v -8.60v sound is absolutely dreadful - very soft and distorted.
TL072N 9.42v +1.20v -7.99v reasonable loud, but very distorted
Touching the underside of the board helped here, too. Connecting a 1M
resistor between pins 8 and 3 (8 and 5 also helped) improved the volume and quality
a lot. The harder I pressed, the better. 0.1uF capacitors did nothing
(I wasn't sure if my fingers were creating capacitance or resistance (or both)).
I checked everything as well as I could. All resistors and connections seem OK - I don't know how to check the capacitors.
In frustration, I built a second Tangent amp and got pretty much the same sound output, although I didn't bother to check for voltage swings, as I was in too much of a bad mood. It seemed clear I was stuck with the same problem.
One thing I did notice - I used cheap op-amp sockets bought from EBay. The NE5532 seems to fit fairly snugly, but the others quite loose. All are tight when plugged into the JDSLabs socket. Could this be the problem? I am getting connections through to the amp, though, as I checked connections to the top of each pin.
I hope someone can help or offer advice. Surely I'm not the first novice to encounter these problems.
Thanks in advance for your help.
Regards,
Mike
I bought a JDSLabs headphone amp awhile ago and thought it was great! I got interested and tried to build a CMOY amp according to Tangent's tutorial. Using an OPA2227PA (from the JDSLabs amp) the sound is OK, although not quite as good. However, when I try an NE5532, TL072 or JRC4560D I have terrible problems.
When I check the power supply with no op-amp plugged in, my 9V battery splits accurately into +4.5v and -4.5v, as expected.
However, whenever I plug in one of the "inferior" op-amps, I get big voltage swings and soft and badly distorted sound.
eg.
No amp 9.4v +4.7v -v.7v
OPA2227 9.39v +3.39b -5.93v sounds OK
NE5532 9.42v +7.44v -1.50v medium volume, distorted
when I put one thumb on the underside covering soldered pins 1-4 and the other
thumb covering pins 5-8 the volume increases and the sound improves a lot.
Checking the voltages again, while touching the connections, the voltages are
closer, but still no where near equal.
I plugged this op-amp into the JDSLabs and got good sound and equal voltages:
9.08v +4.55v -4.53v
JRC4560D 9.40v +0.88v -8.60v sound is absolutely dreadful - very soft and distorted.
TL072N 9.42v +1.20v -7.99v reasonable loud, but very distorted
Touching the underside of the board helped here, too. Connecting a 1M
resistor between pins 8 and 3 (8 and 5 also helped) improved the volume and quality
a lot. The harder I pressed, the better. 0.1uF capacitors did nothing
(I wasn't sure if my fingers were creating capacitance or resistance (or both)).
I checked everything as well as I could. All resistors and connections seem OK - I don't know how to check the capacitors.
In frustration, I built a second Tangent amp and got pretty much the same sound output, although I didn't bother to check for voltage swings, as I was in too much of a bad mood. It seemed clear I was stuck with the same problem.
One thing I did notice - I used cheap op-amp sockets bought from EBay. The NE5532 seems to fit fairly snugly, but the others quite loose. All are tight when plugged into the JDSLabs socket. Could this be the problem? I am getting connections through to the amp, though, as I checked connections to the top of each pin.
I hope someone can help or offer advice. Surely I'm not the first novice to encounter these problems.
Thanks in advance for your help.
Regards,
Mike