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Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => The Newcomer's Forum => Topic started by: stk on August 20, 2007, 06:59:38 PM

Title: Swapping TDA2050 for LM3875 in Vox Cambridge 30
Post by: stk on August 20, 2007, 06:59:38 PM
Hi all. I have a Vox Cambridge 30 Twin Reverb. This amp has a TDA2050. I've read about people replacing the TDA2050 in this amp with an LM3875/LM3876/etc. Example:

http://voxman3.tripod.com/BobAmpPage.htm

I'm thinking about doing this. Anyone done this or know the motivation behind it?

I checked the TDA2050, and it's getting 28V right now. I think that may be too much for it, and hence why the LM3* chips would do better in this circuit. It seems odd to me that Vox would build them this way, but maybe I am missing something?
Title: Re: Swapping TDA2050 for LM3875 in Vox Cambridge 30
Post by: teemuk on August 21, 2007, 04:47:25 AM
Supply voltages are definitely past the max ratings of the concerned TDA chip. Reputedly that amp will also suffer from problems with the optocoupler.
Title: Re: Swapping TDA2050 for LM3875 in Vox Cambridge 30
Post by: stk on August 28, 2007, 03:28:50 AM
Quote from: teemuk on August 21, 2007, 04:47:25 AM
Supply voltages are definitely past the max ratings of the concerned TDA chip. Reputedly that amp will also suffer from problems with the optocoupler.
Thanks for the reply. The optocoupler has already been swapped in this amp. I rechecked the voltage to be sure and it is still at 28VDC. I'll go ahead and put an LM3875 in it and see what happens.
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