Phono 3S conversion - World-Designs-Forum

phats · #1 29th May 2016, 10:41 PM

Hi all,

My name is Stef and I live in the Netherlands. And slowly getting my way around building tube amplifiers and all other audio related gear... I would describe myself as a constructor and not a designer, for instance I know a bit about cathode followers, SE amps, cables and (full-range)loudspeakers. But every time building something I am really depending on advice and design from others....
As such is the case now, I have rebuilt a Yaqin phonostage per instructions from a nice fellow named Les Carpenter. In effect I have built a WAD phono 3S and I was really enjoying it... Without knowing the legacy...
I built it in a wooden winecase and of course it wasn't silent, not even mentioning the 'rat's-nest of building it P2P.
But my skills in routing cables and attention to return-lines has to be bettered as well.
I am planning a rebuild in a metal case, with a separate PSU. But I would really like to swap the ecc83 CF for a ecc88 CF. In my readings and conversations I started to believe the '83 was not really suited for the CF job as an '88 is...

Please, does anyone have thoughts about this, or has someone done this already? Or, is someone willing to design/incorporate an '88 into the phono 3S design?

With kind regards, Stef.

Richard · #2 30th May 2016, 08:58 AM

Hi phats and welcome,

It sounds like you need to get your version of Phono 3S working properly first. Then let us know why you'd like to use an ecc88

phats · #3 30th May 2016, 10:56 AM

Hi Richard,

Thanks for responding (and moving my first post to the correct department), of course you are right and getting it working properly is the first step. Nevertheless I like to mention that it worked properly from what i could tell at that moment. Very good sonics. And, as a musical friend stated; 'it was projecting music like he hadn't heard before". In combination with a low output Denon cart and SUT's it played wonderful.
Noise wise it was flawed and that is where my coming efforts have to be. Mind it was not that bad, it was just there and I know that can be a lot better.

So, I will start building the existing stage in a separate metal box in which I plan to incorporate the first two stages, only the CF will be on top of the enclosure. It will take me some time but I hope to show progress with pictures and occasional drawings of my planning.

I still hope there will be someone willing to collaborate on my hopes for a '88 CF. From what I gather the characteristics of that valve are more inclined to drive a successive stage, ie. lower output impedance and higher current delivery.

Kind regards, Stef.

bob orbell · #4 30th May 2016, 12:53 PM

Hi Stef and welcome, I am not quite sure why you want to use a 88 instead of the 83, if you are following the phono III CD, then it has all been deigned and tested, of course an 88 will work, but I doubt you will tell much if any difference, more to the point, you may be breaching our Administrators copyright. BOB

phats · #5 30th May 2016, 01:22 PM

Hi Bob,

Thanks as well for responding! No, I wouldn't want to infringe in copyrights.... however building this phonostage for a single household, namely our living-room, secures that part, hopefully.
But, as in being DIY'ers, I didn't give it any thought, my mistake I am sure. If this gives any problems for anyone, I will refrain from further action.
But first I just will upgrade my existing 3S clone and try to get in more quiet than it was.

Kind regards, Stef.

bob orbell · #6 30th May 2016, 01:53 PM

Stef, I did not mean to offend you, but it was mentioned just a few weeks ago about members offering WD and WAD schematics to other members, Matthew now has a CD for sale with all the information of past projects, I think that this is the way he want's to share this information, may be a moderator will advise. BOB

phats · #7 30th May 2016, 04:51 PM

Hi Bob, I do not feel offended in any way, I was just ignorant. I didn't realize these phonostages were still in production. (if I understand correctly!)
Perhaps I am a bit naive, but is it allowed to build a 3S diy clone?
I hope to get some information by a moderator...

Kind regards, Stef.

John Caswell · #8 2nd June 2016, 05:27 PM

Hi all,
Although all the circuits are in magazines and on a readily available CD it does not mean they can be used willy nilly, especially for financial gain!
There is no block on building a Phono 3s hard wired or even a new PCB layout, or even faffing about using a 6DJ8/6922/ECC88 as the cathode follower output, though why you would wish to do this I do not know. Changing to a 6DJ8 will not lower the noise floor as it is operating as a C/F. Far better to look at the front end ECC83s and the associated resistors and replace them with lo noise selected valves and possibly bulk foil resistors. Noise on my Phono3 s is not audible at normal listening levels as the measured residual hum and noise wide band is down around the -60dB about 1mV level
Frankly with selected components and care it knocks spots off many commercial designs at much higher prices.

John

colin.hepburn · #9 2nd June 2016, 06:00 PM

Yes I built my phono 2 in the way john has described on the pcb using 5751/ECC83s holco metel film and takman carbon resistors and polypropylene coupling caps and some tweaks to the psu and it sounds great. I also have a phono3S pcb in my to build yet box

Stef My suggestion is why not contact Mathew and see if he will sell you the pcbs and some parts

Some usefully links http://www.world-designs.co.uk/forum...ead.php?t=5819

phats · #10 4th June 2016, 12:39 AM

Thank you all for those kind advises, although I really do not know what 'faffing' means, but it does sound serious!
First , I realize the noise problems do not stem from tube choises, it comes down to using a wooden box as an experimenters platform and some mistakes in grounding/return. There are some builds using wood enclosures, but I guess those are mostly line pre's. My next step will be using a die cast enclosure for the phonostage and a separate PSU. And in this case just with the components at hand and learning (hopefully) how to get it working as silent as possible.
I am quite fanatic in P2P building, I don't really like PCB's, but that is just my point of view.
And when the phonostage was up & running, combined with a SUT and a Denon 301 it sounded quite wonderful with bog standard components.
The origins of this build was a chinese Yaqin MS 12b and it sounded like ****, so with advise from Les Carpenter and the chinese components and PSU it became a WAD clone and was way way better!

Kind regards, Stef.