Evolution 302e Review

[JRDesign]

My 302e is also dead silent but it's good to know Krell doesn't consider the slight hum a problem. Regarding the audible pops, mine exhibits that tendency as well as it is turned to standby and cooling down. I attributed the noise to thermal expansion / contraction of the various metals in the interior as it cools (?) but that is just a guess.

[SteveK]

Mine did not have hums, but it also had loud metallic pop when turn on and off. So, I guess it is normal. Good to know.

[Mr Froggy]

Mine does same sounds after to be turned off. As JRDesign, I think it's due to the response of metals after a termal stress.
After 5 or 6 hours, the Amp is very very hot, and my room's temp grow up by 3degres

[Mikeoz]

Enjoying the 302e - great piece of kit. The mains cable has made a difference. Can't say I understand why but I would recommend trying one if you're using the original cable.

[Mikeoz]

I read you shouldn't use XLR with a tube pre-amp. Anyone know why that is because I connected like that and it seems fine.

[Pojuojuo]

If you have hum noise from your toroidal transformer the most effective component is the PS AUDIO DUET HUMBUSTER. If hum comes from your speakers the problem is in your cables or in a system component

Try to check it

[Mikeoz]

It's defo the transformer - no difference changing mains cord or preamp connections. You can really only hear it close up so I'm just going to ignore it. Perhaps a mains conditioner would eliminate it but I'd struggle to justify the cost.

[New guy]

Originally Posted by Mikeoz

I read you shouldn't use XLR with a tube pre-amp. Anyone know why that is because I connected like that and it seems fine.

Some tube preamp have DC offset which can damage the amp. The RCA inputs on the Krell amp may have DC blocking filters such as capacitors. It will sound better without the additional blocking filters.

I use XLR inputs on my Krell 403E with ARC REF5SE.

Rich

[A.Wayne]

Originally Posted by Mikeoz

I got a reply and they said it was normal with the larger power amps to hear 'some residual transformer hum coming from the power supply area when in close proximity to the unit'

It's not a problem as I can't hear it from the listening position. I just wanted some reassurance the amp isnt about to go bang.

I'm very happy with the sound quality. Will be interesting to see if that exotic power cable makes an audible difference. I'm quite cynical but we'll see.

The noise is not normal , but not unusual either , it could be from over heatng the transformer or dc noise on your supply line . None of the Krells i have had had transformer noise . I do have a temp situation currently with an FPB300cx , runs excessively hot after 25 mins at elevated volume....

Originally Posted by Mikeoz

I read you shouldn't use XLR with a tube pre-amp. Anyone know why that is because I connected like that and it seems fine.

Depends , The BAT tube pre is balanced out only , so no choice ...

[Mikeoz]

Originally Posted by A.Wayne

The noise is not normal , but not unusual either , it could be from over heatng the transformer or dc noise on your supply line .

The words he actually used were 'it's not uncommon to sometimes hear' - consistent with your comment above.

The hum I hear standing over the unit is constant regardless of running temperature. I can't remember hearing it when the guy I bought it from played it in his home (and I was standing right next to the unit when he switched it on).

Makes me think it may be a mains issue. Changing the cable didn't help. The hum is present even when it isn't connected to the preamp so that's not a factor. May try a conditioner on demo just to rule that out.

Must admit I would like to fix it but it doesn't sound like the unit is faulty.