Hi all,
I recently built a (very rough) LM3876 gainclone amp using some Jaycar kits. It sounds pretty good on its own but has no volume control, and managing volume from my PC is a bit cumbersome - so I bought a Little Bear P8 tube preamp on eBay.
Now, the strange thing: if I put the P8 before the gainclone, I lose sound quality (output is lower, there's no treble etc). However, if I put the P8 in front of my old Sony STR-K1500 home theatre amp, it's all good (even if it's little more than a glorified volume control) with no audio quality loss.
Any idea what might be happening here? The P8 runs off a little 12V 3A transformer and is not grounded, however I don't suspect that has anything to do with it.
The amp by itself sounds great - very proud considering its my first build and admittedley a pretty rubbish effort.
Cheers
I recently built a (very rough) LM3876 gainclone amp using some Jaycar kits. It sounds pretty good on its own but has no volume control, and managing volume from my PC is a bit cumbersome - so I bought a Little Bear P8 tube preamp on eBay.
Now, the strange thing: if I put the P8 before the gainclone, I lose sound quality (output is lower, there's no treble etc). However, if I put the P8 in front of my old Sony STR-K1500 home theatre amp, it's all good (even if it's little more than a glorified volume control) with no audio quality loss.
Any idea what might be happening here? The P8 runs off a little 12V 3A transformer and is not grounded, however I don't suspect that has anything to do with it.
The amp by itself sounds great - very proud considering its my first build and admittedley a pretty rubbish effort.
Cheers
Hi Arty,
I actually sorted it out - a previous guide I'd been following recommended a high-pass filter on the inputs to deal with line in noise from laptop/PC sources etc. Turns out said high-pass filter works great when running line in direct from the source, but completely stuffs the signal coming from the pre-amp. Removing the filter has made it work fine.
Thanks for following up
I actually sorted it out - a previous guide I'd been following recommended a high-pass filter on the inputs to deal with line in noise from laptop/PC sources etc. Turns out said high-pass filter works great when running line in direct from the source, but completely stuffs the signal coming from the pre-amp. Removing the filter has made it work fine.
Thanks for following up
Sorry for the late reply, but the issue is all sorted - filters on my inputs were causing havoc. All is well
Also, I made a mistake that I'll put down to my exhausted mental state at the time - it's a Little Bear P5. There's a review/test of it here if you're interested: "Little Bear P5" Line Preamp - somewhat demystified | Audiokarma Home Audio Stereo Discussion Forums
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