[cyclonite]

Hello everyone, I just completed my Meta MINT. The whole board is populated... including the op amp biasing CRD. Anyway now when I listen to music, I get distortion when the sound gets too loud or when there's high level of bass. I am using the OPA2132 op amp.

Any tips, ideas? I'm running on 9v battery only. should I try something else?

 

[myself, aka me]

Put another 9V in series, perhaps that will cure it. Perhaps some of your solder joints aren't done too well - have a look around and resolder dodgy ones. Is the opamp seated securely in the socket?

 

[JMT]

The OPA2132 should be fine with a single 9v. I would definitely check for cold solder joints, especially the SMD components. I would also check all of your resistor values with your meter. You might be surprised.

 

[cyclonite]

Ohh my OPAMP is SMD, no socket. can only use SMD for MINT right?

Could it be my gain or something? btw my earbuds are 32 ohms.

 

[tangent]

Try the second 9V battery in series. JMT's right that a fresh single 9V shouldn't clip in that setup, but there are any number of situations I can think of where you might nevertheless get clipping. This is not necessarily a solution, but more of a diagnostic.

 

[cyclonite]

Whenever you guys use the amp or mention how many batteries to use, are you talking about alkaline 9v batteries or standard zinc carbon?

Thanks.

 

[peranders]

You can use any type of batteries. What type of headphone did you use? High impedance phones and only 9 volts doesn't create lot's of decibell.

 

[jeffreyj]

Quote:

Originally posted by cyclonite ... btw my earbuds are 32 ohms.

Reduce the value of R8 (the resistor in series with the buffer output) to 10 ohms.

 

[SLS]

What values did you use for R5 & R6? If you follow the schematic and use 1.5K & 470K the gain is 313. I did the same thing and it would distort around 1/2 volume. I replaced R6 with 220K and it works much better.

Steve

 

[SLS]

What values did you use for R5 & R6? If you follow the schematic and use 1.5K & 470K the gain is 313. I did the same thing and it would distort around 1/2 volume. I replaced R6 with 220K and it works much better.

Steve