2. amps-preamps
  3. 1374855232

What's causing hiss??

I've got background hiss on a new-to-me tube/ss integrated with a tube pre amp stage. It is constant no matter what volume with no input from source.

Can this be a power problem? Other amps on that circuit with same setup have no hiss.

Tubes getting old?

Defective unit?
tswei99
tswei99 OP
17 posts
 
Amps/integrateds on audition:

Bel Canto e300id
Marantz pm8004
Outlaw 2150
Vincent 236MK
Trends ta-10

Source: apple lossless=>sonos=>ps audio DAC

Speakers: klipsch lascala early 80s vintage, recently recapped

I:ve been trying all manner of combos using pre section with the variuous amps. So far i like the tonality of the Vincent (tube) but noise is very high.

Marantz is very quiet but a bit laid back. Bel Canto is quiet but metallic/cool sounding. Bel Canto pre is very quiet with any amp, Vincent pre is the opposite.
magnumpi205
504 posts
 
Used to run Khorns for 35 years. A new amp/preamp will not solve the problem. The Rothwell shunt is the easiest solution.
Had the Lascalas before the Khorns, dynamics are always incredible.
Would spend my money on Rothwells and new crossovers sold on Ebay.
zd542
5,339 posts
 
Does your PS Audio DAC have any type of gain settings? It could be internal or external. If it does, lower the gain and that will probably fix the problem.
tls49's avatar
tls49
1,351 posts
 


I tried an experiment this morning. I sent the tube pre section out to my el cheapo but zero noise t-amp and the hiss went down considerably. T-amp is 15 watts, integrated is 150 watts, speakers are a super efficient 104 db Klipsch LaScala.
Was the hiss still too high to be acceptable?


Have you tried a different set of speakers with a lower sensitivity? If the hiss is still unacceptable with different speakers, then it would seem that there is a problem with the VincentÂ’s preamp. If the preamp does have a problem, then doing anything else makes no sense until it is repaired.

Mezmo makes a valid response about tubes, however the Vincent uses 3 tubes, one that is common to both channels.
zd542
5,339 posts
 
"Have you tried a different set of speakers with a lower sensitivity? If the hiss is still unacceptable with different speakers, then it would seem that there is a problem with the VincentÂ’s preamp. If the preamp does have a problem, then doing anything else makes no sense until it is repaired."

I agree. If you have the means to try a less efficient pair of speakers, that would go a long way as to finding out the nature of the problem.
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