UPDATE!
Well, just after writing the review above, the KT88 power tubes started to show signs of failure on the right channel i.e. crackles and mains hum
I consulted the guys at The Tube Store (a Hamilton, Ontario web-based store for the Canadian readers) for their opinion.
http://www.thetubestore.com/They suggested either JJ, Winged "C" or New Sensor Gold Lion, and after a lot of reading I selected the Gold Lion because of their reputation for long life.
The initial listening impression was that these tubes were very bright to the point of being harsh. But after only around 5 hours of break in these tubes started to display a totally different character - i.e. detail + control + depth + dynamics
These tubes are now performing amazingly well...
1. Extended low end - I would estrimate about 1/2 an octave lower
2. More detailed low end control - synths have amazing texture to them
3. A richer, more detailed mid range - voices have a more natural sound with a nice lower end to them
4. An extended and more detailed top end
5. Amazingly well controlled high's
-->sibilance is very well controlled
-->brass has a piercing quality without being shrill
-->cymbals and triagles have texture and character
6. Much more dynamic presentation
-->the thump of the bass drum has a dramatic snap to it
-->the tap of a snare drum has a nice sharp crack
-->bass guitar has much more punch to it
-->the sudden stop of a DEEP bass note feels like the air is being sucked out of the room[/quote]
7. Much wider sound stage - way beyond the speaker position
8. Incredibly detailed imaging - much more air around individual musicians - you can count them!
9. On tracks where phasing is used, the sound moves around the entire room and completely envelopes you
Replacing the tubes in this amp has taken its performance to a level that far exceeds what the factory default tubes are capable of and IMHO well worth the expense.
Some might argue that the amp should have come with better tubes, but then the manufacturer has to target a particular price point to be competative. Considering the improvements in performance the new tubes made, suggests to me that Raysonic spent the budget on the actual design and providing other quality components (e.g. power and output transformers), providing an easy upgrade path for the consumer if so desired
The Shuguang tubes provided with the amp produced a very nice mellow sound, which I loved and considered ideal for classical & jazz, but with the Gold Lion tubes, the amp not only gives you a truly amazing classical & jazz performance, but it is now capable of providing a very convincing Rock performance also.
NOTE: The improvements are not only due to the power tubes - I really believe I "lucked out" with the tube combination I have in place. Mainly because I had heard (after buying them) that Gold Lion were a little subdued - NOT IN THIS AMP THEY AIN'T!
Tubes now in place:
- JAN Phillips 5751
- Electro Harmonix 6SN7EH
- New Sensor Gold Lion KT88
