It didn't explode....... YET (aka niges amp)

[nige2000]

Generally like to leave it playing at moderate levels for half hour before been critical, it's smoothes out a little then

It runs cold ...... unless your walls are shaking
In which case it's body temperature if even

There is a signal buffer built in
so I'm not sure what benefit an additional preamp will have

No rush with it back
Especially if no-one else is looking to try it

[Ivor]

Sound.

Not sure about a pre either but curious.

[Georgi]

Is there chance to qualify for a trial? I'm not on group buy or on the market for a amp, but curious. ;)

I'm happy to accommodate a small group for get together and stuff. ;)

[nige2000]

Is there chance to qualify for a trial? I'm not on group buy or on the market for a amp, but curious. ;)

sure.... no problem
might not be as warm sounding as your used to

[Ivor]

I just turned the amp on and when I switched the rocker switch at the mains input there was a definite hum/buzz (I noticed this last night as well when it was on briefly). This was followed by a "spitty" noise that I really didn't like at all!
I assume it should be dead quiet on startup? It's off for now. Obviously.

[tony]

We were having that discussion by email off thread. Tx 50hz hum when you switch on. Just from the transformer. When you do a google search that is a common occurrence. The spitting noise I hope is not an issue. Try it in standby and you will get that TX hum. Then switch back on and see if that is the only noise you have. Playing music is fine just when it is on with no music playing if the room is quiet you can hear that mild tx hum.

[Sligolad]

Looking at the toroidal transformers today and seeing that we do not have any real temperature developing in use (about 30C) it might be possible to design and build a 3D printed split clam shell case for both to help damp the hum.

I will have a look at designing and printing some prototypes next week.
Looks to be room to add thick walled shells with openings for the cables on the bottom and some top ports for air which can be sealed if we do not get any temperature build up inside the shell.

[Ivor]

The hum certainly isn't intrusive, I just flagged it in case it wasn't "normal". That 'spitting' sound went as soon as Nigel was ten minutes away. No explanation, but it's playing beautifully now.

[Fran]

Ivor - any chance the amp was on first and you then turned on the CDP or phono stage etc?

All transformers have some hum (its vibration from the 50hz) and those transformers are pretty big, but not to be confused with hum through speakers. Those of you with valve amps in particular will be familiar with some tiny mechanical noise from the transformers.

[Ivor]

Ivor - any chance the amp was on first and you then turned on the CDP or phono stage etc?

No, as I was rearranging the whole rack I had turned all sources on to be sure it was all 100% before powering the amp up. Phono stage and dac would be always on anyway. The noise was across all sources.