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Vox Cambridge (recent) - low, thin output

3/9/2005 7:06 PM
Lonzo Vox Cambridge (recent) - low, thin output
I tried one of these out the other day (used) and it was extremely thin and had very low output. I have played through these before and found them to be a decent sounding little amp - not like the used specimen I came across. Any ideas of a cause for the low output?  
3/10/2005 2:45 AM

I'll bet my lunch money it is a bad trem opto. I think the part is an LT9912 or some such.  
Short the legs together on it, and if the sound comes out gangbusters, then I am right.
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3/10/2005 3:53 PM
Thanks for your assistance.
3/25/2005 2:06 PM
Rick Erickson

If it's a Cambridge 30 Reverb I would also look at the supply voltages on the Output device, a TDA2050. The TDA20XX series IC's will go into a protect mode when over-voltaged and either shut down or distort badly and get very thin sounding.  
There is information on the web about replacing the output device with an LM3875TF. I have done this conversion and it works very well. You won't get more output power though, even if you use the higher power device they mention. Seems to be a bit of confusion regarding device specs and actual output.  
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