Caiman passive output mod revealed

**RoboCopper** · 01-09-2010, 22:08

I just checked by touching the connectors where I have soldered the capacitors for the mod from the post 1 of this thread and when touching with small screwdriver the speakers are producing the crackling sound, meaning that there is some signal coming from that point, also when touching the opamps board, same sound is coming out.
Could something be wrong with input stage of the 7520? Static?
p.s. I also used can spray for blowing air in order to clean all possible shortcuts (e.g. under the DAC 1716 chip).

**RoboCopper** · 02-09-2010, 07:38

Here are some photos.

**StanleyB** · 02-09-2010, 09:14

Can you provide a picture of the back of the fixed RCA socket? It is not clear whether you have soldered them back correctly.

**Puffin** · 02-09-2010, 10:36

Originally Posted by StanleyB

Try it and see

.
I thought I had an updated picture that showed the soldering away from the DAC chip pins. It's best not to solder the wire directly to the DAC pin. If I can't find my other picture, Use a multi meter to trace a better spot from the wire on pin 15 of the PCM1716.

So this takes power straight to the +5v IN. I suppose you could make a separate PS for it?

**RoboCopper** · 02-09-2010, 10:43

Originally Posted by StanleyB

Can you provide a picture of the back of the fixed RCA socket? It is not clear whether you have soldered them back correctly.

Hi, I think they are, but here are more photos.
Regards

**Alex_UK** · 02-09-2010, 15:48

I've finally decided to do my first ever mod! I hadn't realised I could do this without soldering anything, so ordered some Rubycon Bi-polar 47uF caps from Tirna, (4, just in case, I know what I'm like...) and then I can see what the fuss is all about by taking the op-amp board out. The only slight downside is losing the Headphones, but I only use them rarely anyway, and I can always get brave and do the other method if the headphone out on the Creek is awful...

Should be fun, can't wait to see how the mod sounds.

**Clive** · 02-09-2010, 15:51

Originally Posted by RoboCopper

Hi, I think they are, but here are more photos.
Regards

Are you sure the phono socket is making a good connection with the phono plug? One looks rather fried.

MartinT · 02-09-2010, 16:27

Alex - allow a full week for the capacitors to settle down. Rubycons are a good choice. You should hear a sizeable improvement over the op-amps provided your preamp/amp's inputs are high impedance.

**Alex_UK** · 02-09-2010, 17:53

Thanks Martin - I'll do what you do I think, and leave it running 24/7 with Sky - if they should make it here tomorrow that would be great as we are away for a few days. I'm actually also hoping the output will be a bit lower because the Phono board I've fitted is noticeably lower than the Caiman currently, so might even things up a bit and stop me waking the neighbours when I switch from the turntable! No idea what the impedance is on my Creek amp as it doesn't say in the manual, although all line-level inputs are said to be the same 415mv sensitivity.

**RoboCopper** · 02-09-2010, 19:35

Originally Posted by Clive

Are you sure the phono socket is making a good connection with the phono plug? One looks rather fried.

I wish that was the problem, but there is no sound coming out on variable RCA outputs (and fixted) where I did not touch them at all.
In fact there is popping sound coming out of fixed ouputs, but only when volume is at max volume and when switching the inputs.
Thanks for suggestion though.

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