Inexpensive KEL84 Upgrade

[misterc6]

I'm not sure if this has been mentioned before, but I've noticed a significant improvement by replacing the ECF80s with E80CFs. I've tried Mullard and Telefunken to good effect. I'm particularly pleased with the ones in the link below at £40 the pair including postage:

https://www.ebay.co.uk/itm/275768776481?hash=item4035199721:gY4AAOSwdWRkJsV 8&amdata=enc%3AAQAHAAAAsEQm9IBQSi6DG%2FsLCyMOLFnI2 %2FXMGeNqGcqsYdG2DPM39vBVg244rfcnVRJq5AyKQcdKQhNRV RNF0nohkoCGc0wkrGi8T2LNiuQ9ASwpZTsJE3nhNAMEOVVNM60 T1koezIAaOTutHmG0VZ%2FDy5bmenVR0HSBF3ERKd5rWyYseZm PleWaYL2PmojSaZJ%2FutWFvckFVhnu%2B8kMQOBqdotJB9gbS 94TOS5iddZOXH3p725%2F%7Ctkp%3ABk9SR66nz77pYQ

[Mark]

What brand were the ECF80s you replaced ?

[misterc6]

Originally Posted by Mark

What brand were the ECF80s you replaced ?

Hi Mark,

The Ei ones from WD. Mullard with both circular and square getters, Cossor.

Malcolm

[bob orbell]

I shall not respond to any more of your posts, I find you completely ignorant.

[John Caswell]

Knock it on the head Bob or I will permanently. That comment wasntotally unnecessary and extremely rude. I suggest an apology is required

John

[John Caswell]

Hi Malcolm,
Yes this effect is quite common. Mullard's industrial valves were specially selected, vibration and knock/drop tested and then checked again before dispatch.They also benefitted from a one year warranty, unlike the standard ECF80 which was only covered for 90 days. As you may surmise they of course cost more.
If you look in the FAQ you will find I did some exhaustive tests on ECF80/E80CF as there were a lot of complaints that the voltages were all over the place. My conclusion was that it made absolutely no difference to the gain/distortion figures.
Personally I am not is a position to comment on sound differences as I now wear hearing aids, so have to rely on others ie the lady wife.

John

[Mark]

Originally Posted by misterc6

Hi Mark,

The Ei ones from WD. Mullard with both circular and square getters, Cossor.

Malcolm

Malcolm,

Thanks. The reason I asked the question is that it's good to know what brand of ECF80 you thought the E80CFs were better than.

I had no problem with the sound quality of the EI ECF80s supplied with the KEL84, but I was concerned about the voltages being out of the spec in the instructions which I thought meant there was something wrong. I also thought they were too microphonic. The voltage issue was kindly sorted by (Dr) John - there was no problem - the amp checked out fine. Someone on this forum then kindly gave me two Mullard ECF80s. I can't remember if it was to solve the voltage or the microphony issue, but it certainly solved the microphony issue and improved the sound quality. You may therefore also like to try some other brands of ECF80s in addition to E80CF.

Mark

[Mark]

Originally Posted by misterc6

Hi Mark,

The Ei ones from WD. Mullard with both circular and square getters, Cossor.

Malcolm

Malcolm,

Thanks. The reason I asked the question is that it's good to know what brand of ECF80 you thought the E80CFs were better than.

I had no problem with the sound quality of the EI ECF80s supplied with the KEL84, but I was concerned about the voltages being out of the spec in the instructions which I thought meant there was something wrong. I also thought they were too microphonic. The voltage issue was kindly sorted by (Dr) John - there was no problem - the amp checked out fine. Someone on this forum then kindly gave me two Mullard ECF80s. I can't remember if it was to solve the voltage or the microphony issue, but it certainly solved the microphone issue and improved the sound quality. You may therefore also like to try some other brands of ECF80s in addition to E80CF.

Mark

[misterc6]

Originally Posted by Mark

Malcolm,

Thanks. The reason I asked the question is that it's good to know what brand of ECF80 you thought the E80CFs were better than.

I had no problem with the sound quality of the EI ECF80s supplied with the KEL84, but I was concerned about the voltages being out of the spec in the instructions which I thought meant there was something wrong. I also thought they were too microphonic. The voltage issue was kindly sorted by (Dr) John - there was no problem - the amp checked out fine. Someone on this forum then kindly gave me two Mullard ECF80s. I can't remember if it was to solve the voltage or the microphony issue, but it certainly solved the microphone issue and improved the sound quality. You may therefore also like to try some other brands of ECF80s in addition to E80CF.

Mark

Thanks, Mark

The build instructions do mention the ECF80 voltage variations and they are not a problem as you say. It seems to be a thing with triode-pentode valves. My experience is that there's less microphony with the E80CF and more space around the instruments and voices if that makes sense.

I've been building electronic equipment for over sixty years now but there's still a lot to learn. I built a K5881 PSE when it came out and still find myself wishing I'd not sold it on. In the last 12 months I've built two KEL84s, a Phono3 with PSU3 and reworked another Phono3/PSU3 pair. Many thanks to all those who helped me with these and a special thanks to Greg and Matthew.

[Mark]

Originally Posted by misterc6

Thanks, Mark

In the last 12 months I've built two KEL84s, a Phono3 with PSU3 and reworked another Phono3/PSU3 pair. .

That's impressive ! Were both KEL84s for you ?