KEL84 advice -please...

[Bonky]

Newbie here, and completely new to Valve amps (although I do have a Schiit Saga pre-amp). I have been contemplating an inexpensive valve power amp - just to put toes into the waters. At present I have a Saga + DADA-modded Quad 306 + Living Voice speakers (efficiency: 94dB. 6 Ohms).

As I don't seem to be able to source a 2nd-hand KEL84 (I just lost one on the AoS site (£350)), my mind turns to a KEL84 kit (yes I can use a soldering iron).

My questions are:

1. If I buy the 'improved' version of the kit (a power-amp...NOT the integrated version), what simple extra mods may be worthwhile?

2. Would the (considerable) extra outlay on the KT88 be a better bet in the long run?

I will be near Totnes soon so may go over to WD to collect.

Thanks.

[bob orbell]

Hi Bonky and welcome, all this depends on your ability to build the amp's, the KEL is PCB based, and therefor so much easier, the WA88 is all point to point wiring, and more difficult, plus, the WA88 is more powerful, you should not need much power if you are going to use your mentioned speakers, if you do chose to build either, build in standard form first, and spend some time getting to know your new creation, there is a lot of help on here if you have any questions during your build. With all Hi-Fi a better cleaner power supply is most beneficial, and this would be my first advice on upgrading. BOB

[Bonky]

Hi, thanks for the welcome and advice.

My mains supply is 'cleaned' by a PureSound AV except for the amp which is plugged directly into an unswitched wall socket (this seems to be the advice in so many forums). Is this what you meant by a better PS?

I was just thinking that whilst I was busy soldering the giblets into the case I may as well incorporate any simple mods...but your advice is to stick to the original design ....Thanks; makes life easier!

Best wishes,

Richard / Bonky

[bob orbell]

Hi Richard, no, I do not mean mains conditioners, when I say a cleaner power supply, I am referring to the high voltage DC that is, inside and powering the amp. and consequently driving the speakers, albeit, now oscillated by the amp, a better power supply. BOB

[Bonky]

...I thought not Bob; thanks.

What PS would offer an upgrade?

(Nothing to do with £100+ 'audiophile' fuses I hope! (http://theaudiostandard.net/thread/2...diophile-fuses))


Richard.

[bob orbell]

It is just better components after the transformer, diodes (Shottky) or other fast recovery types and low ESR (equivalent series resistance ) capacitors, for the likes of Evox Rifa. Try and find out more about the subject, it is all part of the upgrades available for WD products. BOB

[Bonky]

Originally Posted by bob orbell

It is just better components after the transformer, diodes (Shottky) or other fast recovery types and low ESR (equivalent series resistance ) capacitors, for the likes of Evox Rifa. Try and find out more about the subject, it is all part of the upgrades available for WD products. BOB

OK; thanks again Bob.

The more expensive version of the amp does have Schottky diodes etc.

Richard.

[Bonky]

Well, thanks everyone. The KEL84XL kit has now been ordered...

I have a few questions:

1. I have at home 2 sig gens and a ‘scope. (I’m not adept at using them though!).

Are there any tests I can do on the finished amp using this equipment?

2. Do you favour those anti-microphonic rings on the non-power valves?

3. How critical is the placement of the amp? (I’m thinking of putting it on a shelf in place of the Quad -but this will mean less than 6 inches of headroom.) I’m wondering about cooling…

4. I'm just pondering making some IPL-Acoustic Transmission Line speakers -but they are only approx. 88dB efficient. Would the KEL84 struggle a bit? (Living room 12 x 17 x12 (feet))

Many thanks.

R

[bob orbell]

Just wait till you get the kit, unpack, make sure it's all OK, then build it as instructed and test as instructed, question 2, if you want to, try them, I doubt you will hear any difference, question 3, should be fine, but what is above will get quite warm, question 4, the amp will drive 88db no problem. BOB

[Phil Y]

I would second what BOB says,

The only test equipment you need is a decent quality multimeter. There are relatively high voltages in the amp so for your own safety you don't really want to be using some £10 from ebay job.
Sig gen and scope are more for fault finding or development work. The KEL84 is a well sorted design, if the DC voltages are right it will almost certainly work correctly.

Those damping rings may be a benefit on a phono stage but on a power amp I would doubt it.

Cooling should be fine on a shelf as long as it is open, ie no back and sides.

The amp will work fine with the IPL speakers, the only limitation would be if you like your music very loud then it might run out of puff.

Regards, Phil.