Are the Pre-outs on my Pioneer 2011 Poor Quality ?

connected to a Rotel 985 MK II Power amp

get a low level but slightly annoying "whine"/hum noise - too high pitched for 50Hz noise (I think) - not sure how to describe it - but its not a clean sounding hiss.

For one channel say- Remove interconnect from Rotel - noise gone

Rotel on - interconnect still connected - but Pioneer off - noise gone

Rotel on - Pioneer on - annoying whine

Does this just mean the pre-outs are of rubbish quality then ? or anything I can do to improve things ?

Tried plugging each into different mains sockets - and same problem.

thanks for any help,

Mark.

 

well I've removed 60% of the whine - was a Strontronics PSU that powered the IR converter into the TIVO box.

even with this small PSU not plugged into the converter - still gave all the noise out of the speakers - so must have been very poor quality ..

I then tried another PSU - worked fine - with no noise - but somehow and I have no idea how (PSU was right rating, right polarity etc etc) - I caught the metal case of the converter - green flash - converter no more ...

every cloud has a silver lining though - as I found a different code to use on the TIVO and I found I don't need the converter anyway..

now to find the other guilty party - will try not to blow the next one up though !

Mark.

 

good work !

the weak point of most pre's is the volume pot then the psu IMO

if you don't need a remote ..think about getting a passive pre there are some stonkingly good kits on ebay ...

http://cgi.ebay.co.uk/4-Channel-Aud...10596QQcategoryZ14974QQtcZphotoQQcmdZViewItem

and

http://cgi.ebay.co.uk/Audio-Input-R...12477QQcategoryZ14974QQtcZphotoQQcmdZViewItem

I've built both ....from this chap

 

thanks Zanash - unfortunately its an AV amp - so would be missing out a bit with a passive pre-amp

one of lifes compromises I suppose since I listen to 90% films 10% 2 channel stuff

while you are on here Zanash

I keep thinking I should modify my Toshiba DVD player for 2 channel playback - apparently its got great Upsampling DAC (well I think they are anyway - they are Analog Devices AD1955s -uses all 6 in 2 channel mode) but spoilt by the worst ever op-amps - NE5532

insides look well built to me anyway - the 2 channel just doesn't seem to cut it - due to the op-amps perhaps -I'm not sure ?

 

I think I'd better start a new thread on this one ! in DIY

 

yah - and found the remaining 40% of my hiss/hum on my speakers ..

unfortunately not such an easy one this time - is the BFD P1124P

used to equalise my sub - but hum/noise is on my main speakers.

turn off the BFD - and silent as a mouse - not even any hiss

must be a ground loop - but any ideas how to remove please without (1) removing earth which is not very safe or (2) spending a fortune on a transformer ?

thanks, Mark.

 

bit like a monologue ..

but found a fix - seems "commoning" the ground works - if I put the end of a piece of speaker cable onto one of the AV Amp's chassis screws, the other on the chassis of the BFD - noise gone completely - presumably this will do no harm ?

thanks, Mark.

 

Try disconnecting the earth at one end in the interconnects that connect the equaliser to the pre-amp.

 

just tried that - to no avail

tried doing the ground to ground connector properly - wire connected to case of BFD and "ground screw" on AV amp ...

guess what - didn't work this time !

very finnicky - touch the wire on the any of the Pioneer AV amp chassis screws, and the ground hum disappears or gets worse - depending on how hard you push/how good a connection you get to the screw ! and its not the harder the better either - a really gentle - hardly touching is the one that completely removes the hum - but its obviously not possible to fix it like that all the time.

any ideas please ? thanks, Mark.