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JohnG 30th January 2017 08:19 PM

Klp1
 
Hello
I am a new member to WDF and am feeling good about being able to access a community that enjoys the WAD projects.
I have been associated with WAD since the mid 90's, until about 2004, then after a series of house moves and other things, the HiFi remained in storage
until december 2016.
I have never built a project, these were done by the same valve engineer.
We are at present re-establishing our system, to how we remember it.
As well as going forward with a completion of partially finished projects.
We have also expressed the wish to upgrade some of the components to extract a little more in replay performance.
At present we have a KLP1, K5881 - MK1, Andy Groves design, solid state phono stage. ESL 57. A Goldring Lenco 75 overhaul and new plinth project began in January 2017.
As a initial upgrade I would like to find out if the KLP1 will benefit from improved components, and as it will also be a supporting pre amp for another power amp project that is 50% complete, I was informed it will need more gain.
I would appreciate any ideas on how to improve the KLP1 as well as add gain.

John

bob orbell 30th January 2017 08:43 PM

Re: Klp1
 
Hi John, the KLP1 is a strange product, I think that I am correct that it has two valves, using only half of each valve, it is a cathode follower, John Caswell has the CD drawings, the heaters are AC :confused:, and it has a full wave voltage doubler, 100 volts from the transformer doubled to 200, I put one together last year from bits and I disposed of it for it was no good, you will not be able to increase the gain as it is only unity gain, a buffer. BOB

davebms 30th January 2017 10:11 PM

Re: Klp1
 
hello all,,, (quote) disposed of it for it was no good,

that's a bit harsh !! I had an article on kpl1, it might have been in the old
WD forum,, the thoughts were that it was ok,, ,but the power
supply was not up to the job ,, does john need more gain ?

dave

JohnG 31st January 2017 06:13 AM

Re: Klp1
 
Thank you
I suspected there was a limit to the upgrade path, as the klp1 has not received much coverage on this subject.
I am happy to be open minded, and look at a new DIY line stage pre amp, utilising the Klp1 casing as a housing.
Which DIY model would be a affordable and improved build.
It will eventually, have a valve phono stage go through it, and be working with 845 push pull mono blocks optimised at 25 watts.

John

pre65 31st January 2017 09:00 AM

Re: Klp1
 
845 push pull monoblocks ?

That's ambitious.:D

Is it worth the complexity (and cost) for 25 watts ?

I'd like to hear a bit more about the parts you will use, particularly with regard to output transformers.

Richard 31st January 2017 10:02 AM

Re: Klp1
 
Hi John and welcome.
Perhaps you can tell us the sensitivity of your power amps.
Many power amps these days are line sensitive (typically 300-500mV) and sources usually have enough voltage to drive them (typically 500-2000mV).
That leaves some power amps needing 1-2V in something of a minority.
Many preamps have become buffers/vol control/selectors rather than amps per se. Others like WAD Pre2/3 have good gain as designed but if (for the previous reasons) folk don't need the gain they convert them to unity buffers.

JohnG 31st January 2017 06:00 PM

Re: Klp1
 
Thank you all for your replies,
If I supply a little history about my HiFi project, it may help answer why some of my answers will be vague.
Firstly, I am not a electronics engineer, especially from the valve discipline.
All my projects were completed by a very experienced valve/electronics engineer
who I have a high regard for, the past years have only confirmed to me of his honesty.
Many years ago when at his work shop, I was familiar with the sound of a single valve 845 mono test amp he had built, it was basically a amp devised to allow the 845 valve to be thoroughly tested.
The presentation of this simple design had my attention and I started looking into 845 valve amps, these were demanding serious asking prices, so I was a bit of a tyre kicker in the 845's respect.
Them I went to the Ramada Show, with my wife and valve engineer friend.My wife and I had the opportunity to listen to our favourite group through 845 driven ESL 57, our favourite speaker in the EAR room.
Our valve engineer friend got into a discussion with TDP, and was not politely removed from the room. A little embarrassing but very memorable.
The 845 ambition fuse was lit, until eventually a good in depth discussion took place about the ideal parameters of usage for my requirements .
So I funded a schematic and a R&D on the project.
When the measurements started making sense the output amps required were not available of the shelf, so hand wound ones were made, If I recall correctly it was all about the primary windings.
When the output amps were produced, when these were in being produced, the power supply came to the fore,.
The finished power supply is a separate unit weighing many Kgs with three separate power to amp cable connections between power supply and monoblock.
I took the amp case to a powder coaters, and a 50% project was completed, it was tested for many hours and more.
This sat in the engineers premises for multiple years, "way to many" the project was brought home in December 2016 with the second monoblock case needing to be welded, polished and powder coated, I have just authorised the second power supply to commence, I have estimate of completion costs so will hopefully have it in its entirety for around June.
To get a feel for the delivery, I have a split phono plug and shared speaker cables driving Tannoy cheapo speakers from a, never should own, CD player, as a family we have never heard CD on our system, we are gobsmacked by what we are hearing.
For me CD is on the menu, I did a short hook up to the ESL just to get a feel, WOW! I had a wide deep soundstage, I could feel a guitar sitting on Cat Stevens Lap. The risk of a 2ohm or less loading meant the quads were short lived as a speaker so the Tannoys are the booming ,boxy, John Lee Hooker loving speakers at present.
The family are very pleased to have seen a return to having a HiFi system as a priority, they are saddened I recently sold my Granite plinthed 401, and in fairness so am I. Onwards and upwards the GL75 will be more than enough for our needs, weighing in at a few stones, (21Kg), unlike the 401's nine stone, (64Kg).
So with these ongoing events a Pre amp to make the most of it is now on the to do list.
I am hoping to receive a guidance on the Pre Amp direction, as I am a long time absent from such discussions.

I

westiebj 7th February 2017 12:23 PM

Re: Klp1
 
2 Attachment(s)
Hi

I have recently built the Phono3 and PSU3 kits using an existing WAD KLPP1 case

Matthew at WD was very supportive and happy to provide kits minus the cases and assorted pieces of HW no longer required

I believe a similar result could be achieved using the KLP case ( I think its the same as KLPP1 ) and the WD Pre3 / PSU, although you would have to check the sizes of the Pre3 PCB

I am very happy with the result ... the Phono3 is still burning in but the sound is excellent, far better than my original KLPP1

I have attached some photos showing the layout plus a new perspex faceplate which I chose to match other kit I owned

Rgds

westiebj 7th February 2017 12:23 PM

Re: Klp1
 
2 Attachment(s)
Two more pics ..

bikerhifinut 7th February 2017 12:42 PM

Re: Klp1
 
That's nice!

now I know what i'd do if I was the OP.

I'd get a Phono3 kit sans case and the parts to make a preamp of choice, it looks possible to squeeze a pre3 in there or easily put a simpler circuit in alongside it.
Then I'd add an offboard PSU which gives the advantage of flexibility of PSU choice and complexity. And reduce or eliminate any danger of PSU noise and hum getting into the sensitive disc stage. The Phono 3S has the capability to be totally silent in terms of hum, it's only valve Hiss that I usually hear with mine.
Ah yes isn't that what i am considering to do with the prototype preamp case I obtained off Nigel a couple of years back............ thats based on the WD headphone amp case so there's an idea for those thinking of an "all in one".

At the risk of being pilloried by the die hards and forced to do penance, I have to make a big confession here. I often use a solid state preamp. it's a Rega Cursa3 which is a very transparent piece of kit, very like a passive with "drive" for long cable runs that I use. This as well as a Broskie Aikido cathode follower as I do not need gain for my power amps. Depends on my mood. But the rambling point i wish to make is don't discount silicon as those pesky op amps and transistor things can be made to work very well with valve power amps.
Again I am using at times a very good solid state disc stage that for me just works. I like to keep an open mind and don't disregard any technology out of hand and i think its good to compare old and new technology.
to Bob O, I will have to get a pair of those resistor values you mentioned as my phono3 although very sweet does seem to miss a bit of "mojo" and perhaps thats the synergy thats missing?

A.


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