KT88 conversion to integrated

[Bonky]

Yes, thanks everyone; understood.

Best wishes,

Richard.

[Bonky]

My KEL84 has now been converted and is working perfectly ...no need for a pre-amp.

I did not do the 'earth-lifting' mod in the end. I decided to wait and see if the hum decreased with the removal of said pre-amp. I believe it has.

R

[Greg.]

Richard, It would be cheap and easy to introduce an earth lift network anyway. Why not give it a try and see if things sound better?

[Bonky]

Yes, I could, but I've suddenly recalled that I disconnected the earth wire from the mains lead many months ago, relying on the grounding from the various leads going to/from the pre-amp. Now that the pre-amp's gone I think I'd better reconnect and see if I get an earth loop.

I'll take advice of course....

Richard

[bikerhifinut]

I haven,t got a copy of the KEL84 build instructions any more since I moved mine on.
But I'd be very surprised if the KEL84 as standard didn't have the 10 ohm earth lift resistor/0.1uF capacitor fitted. That's why I was confused about all this about earth lifting on the WD amp. Any earth loop issues to my thinking will have been around the preamp.
As I remember it, the KEL84 was as quiet as a mouse on any source I tried with it.
Richard, get that mains earth connected ASAP! there's a reason for it!

Andy.

[Greg.]

Well, Andy, I ‘ve checked the instructions, circa Peter Comeau era, and certainly he did not incorporate an earth lift network in the KeL84. Matthew may have subsequently changed this, but I have no idea.

[Bonky]

"Richard, get that mains earth connected ASAP! there's a reason for it!"

Don't worry ...it's first on my list this morning.

Edit: The amp WAS earthed after all...it was my pre-amp that wasn't. My poor memory!


Matthew wouldn't have sent me the two earth-lifting components if it had already been incorporated(?)

...I'll ask Matthew...but I think he's away for a couple of days.

Thanks again,

Richard.

[Matthew Snell]

Just to confirm, KT88 is supplied with the earth lift, but KEL84 is not. No reason - other than inertia.

I haven't had any reports of hum in KEL84 in the last nine years. If anyone wants to chip in with "theory" on this it would be lovely to hear.

While I've occasionally suggested the earth lift for stubborn hum (so far always in other contexts/set-ups), I would never suggest disconnecting mains earth other than for diagnostic purposes and under controlled conditions.

... I hope that's clear!

Matthew

[bob orbell]

I think that Bonky (Richard) my have been mislead by the earth lift and completely removed the earth cable from the chassis , I hope I am wrong, the KEL 83 has 0 volts and chassis earth common, the earth lift resistor and capacitor (in parallel) separates 0 volts and earth. Bob

[Bonky]

Originally Posted by bob orbell

I think that Bonky (Richard) my have been mislead by the earth lift and completely removed the earth cable from the chassis , I hope I am wrong, the KEL 83 has 0 volts and chassis earth common, the earth lift resistor and capacitor (in parallel) separates 0 volts and earth. Bob

Hi Bob, I easily get confused these days - but not on this issue, (except as I added to an earlier post of mine...I was wrong ... as the earth cable to the Kel was intact after all. I had taken it off the Shiit Saga preamp).

I am fully aware of the need to 'earth' such equipment - especially with such high voltages.

Expectation bias perhaps, but I think the amp without the preamp sounds better than it did before...And it looks better!

Thanks everyone,

Richard