Hello there! I'm a brand new Graham Slee community member with my first Graham Slee Headphone Amp. It arrived last week so not that long time spend with it but I could say from the first moment that this is SOMETHING! Paired with Grado GS2Ke the music comes alive! Beautiful, beautiful music. My references are Crekk OBH21SE (my best so far), Arcam rHead (dissappointed) and Cambridge Audio DacMagic Plus (good DAC, bad AMP). The only disadvantage I could think of so far is quite a bit of background hiss. But Creek does it too and I love the sound so much. Looking forward to new adventures in hi-fi! 

The hiss issue you are getting I think is the norm for most headphones listening I'm sure, That said I also have speakers and I hear hiss from them when not playing music, As I always keep my HiFi on (powered up) You are right about built in headphone amps they are not always the best sound I had a amp with one built in and it was not as good by a long shot as my Solo.

I see from your pictures that you listen mainly from digital is this right?

What sort of set up have you got?

I have CD player and a record deck, I have just started ripping my CDs so that my change.

It seems you have chosen a good headphone brand to pair with your amp a lot on this forum seem to like them.

Jonathan

Hello Jonathan,

thanks for your post! All my listening has moved to work while I currently have 2 little kids running all day at home playing (destroying) everything they come across:) My turntable, amplifier and speakers are carefully packed and waiting for them to grow up a little. Hence "only" a headphone setup: PC - Roon running Tidal - Audioquest Jitterbug - Supra USB cable - DacMagic Plus - Chord RCA to Graham Slee SUL - Grado sr325e / Sennheiser HD600 / Grado GS2000e. 

I also have HD600s but the 2019 models and they are great, a bit lacking in bass for me but the Lautus cables I replace the old ones with made a big difference (from the amp to the Solo) I have just put a order in for two pairs of Cusat50 cables to go from the turntable to the Reflex M to the amp so that's going to make a difference to my vinyl listening. I have all read got Cusat50s from the CD player to amp.

that's gone well over my head (understanding) I have always had the hiss issue and have taken it as part of listening to music (the quit parts), As long as it does not interfere WITH the music I don't mind. As we all know even listening to live music you have had noise in the quite parts it's just something you put up with. It's also something listening to vinyl you have to put up with (back ground noise), But with GS phono amps that is reduced a lot.

I must admit I don't understand half of what you are saying but I am genuinely interested!:) I have the same experience that low impedance Grados do hiss but higher impedance Sennheisers (like HD600) don't. So you are saying that using a voltage divider cable can lower the hiss without compromising the sound? How would I go on about doing that in my case? I tried googling to no avail. Thanks in advance! 

This might be better explained by Graham as I don't understand it 100% myself. But the hiss you can hear is determined by SNR (signal-to-noise ratio) vs load impedance vs electrical sensitivity of the load.

(Impedance matching)

By hiss, I mean background noise produced by the amplifier stage (not background noise in the recording) most audible when no music is playing. Graham has said something very important about amplifier hiss in the past, in that trying to design the electronic circuit to silence it completely will detrimentally "kill" other more important qualities of the music signal so he avoids doing it for this reason. It's a juggling act.

yes that's better, I can see how it can kill the music quality as not all noise is bad (trying lose all noise) as we all know but as I said the hiss is something I'm use of. I have CDs with back ground noise in the quite parts that has to do with the way it's recorded, I don't think you can have totally quite parts if you wont the best sound quality and to hear all the music. For Graham this must be very hard work indeed.

As you say, if there is surface noise with vinyl and background noise in live recordings, trying to totally eliminate amplifier hiss serves no purpose whatsoever and filters don't discriminate between signal and noise so both get attenuated. The designer is spinning multiple plates on sticks simultaneously, trying to preserve the whole picture. It takes a great deal of care and attention to detail.

The Diamond Edition is intended to drive difficult loads like Grados better, with a lower noise floor. You will likely experience a significant reduction in hiss, without any loss of musical qualities. This option will be easier and probably cheaper than trying to calculate component values and buy materials to make a custom cable for the headphone to alter its load/sensitivity characteristics.

I'm confident Graham and other members here would also echo my ULDE recommendation for your intended use.

Selling headphones you no longer use and selling your UL board after getting the ULDE may pay for it completely without further investment.