Solo UL noise cut ten-fold!

j633295 wrote: Graham, I primarily use my original Solo UL with Grado SR325is & PS500. Since all Grado cans are 32 Ohms, would you recommend all Grado users to upgrade their original Solo UL to the revised UL?

Only if I were in this for the money alone.

I wouldn't want anyone to think I'm doing this sort of thing to string people along to make additional income for my business every now and then.

The "design brief" if I can call it that, was from a major distributor who felt the Solo Ultra-Linear was too noisy at -78dB for highly sensitive headphones. After numerous tests I did, I came to the same conclusion, that, in using really sensitive headphones, especially the in-ear types, that background "hiss" could be a nuisance.

In tackling the noise I wanted to at least preserve most of the virtues of the UL concept. I obviously wanted it to still do a good job with the vast majority of headphones. The problem was that initially the reduced noise "prototype" didn't quite hack it with an old pair of Grado SR60's, which I know lots of people own. OK, they're a budget Grado headphone but I'm sure they must share some of the qualities of the higher Grado's. Therefore I admit I put a bit more effort into getting better results from them than from the existing UL.

What we need is to send the diamond edition UL out to our loaner program moderators for loan to curious members. I'll now put four units into production for that purpose.

The diamond edition upgrade cards are now replacing the original UL so anybody ordering a factory upgrade or DIY upgrade gets this.

I sure look forward to hearing this new diamond edition unit. Thanks.

j633295 wrote: Diamond Edition factory upgrade ordered. Eager to hear the difference.

Ooh, please say you'll post your views

Reporting to Base..... Diamond Solo UL has been left on for over 4 weeks now and I guess the initial stage of burn-in is more or less complete? There are some notable improvements over Solo UL MK1: 1) Much less hiss (I can hardly hear any hiss during low passages in tracks) 2) It certainly has improved on soundstage when paired with the Grado PS500/SR325is (32 ohms). I feel like I can now identify where instruments are located or positioned - and that's fun! In the past, I felt everything was thrown at me in 2D compared to now which has added depth and better separation of instruments. On the other hand midrange (vocals) now feel more distanced. Nevertherless, I do feel that the Diamond UL Solo now drives Grados much better than before. It is a worthwhile upgrade! Thank you Graham!