DIY phonostage.

[337alant]

Thanks Si will do

Alan

[6L6]

Simon -

Thanks for the pics! It looks great, and I am looking forward to seeing it all cased.

I have an unhealthy obsession with high-end DIY phonostages... I have built 4, and would like to do at least two more...

The problem is that my Pass Pearl (original) is pretty much perfect. The Pearl 2 is also amazing. So, as with most people and DIY projects, I need to do another phonostage about as much as I need a syphilis infection.

That said, it's likely not going to stop me.

I will get to it in time, as I literally have 2 amp projects unbuilt (with one started and needeing to be finished in no longer than a fortnight) and another power amp that has a hummm, and needs debugging.

All that, and NASCAR season is starting mid-february... (I'm a Learjet Captain for a company that owns a race team) so I am in a genuine rush to get these going.

[The Black Adder]

Hi Simon. How much would this stage cost to make as I'm looking in to a DIY stage myself.

[sq225917]

Joe, first off it's not available the group buy is over and done. You might see one come up on the DIYaudio.com classifieds if you are lucky. pcb and group buy parts kit should be about 150 quid, maybe a bit more. The trouble with that is the group buy transistors are dog shit and you'll need to buy another 500 to get the correct matched values. So all in with cases, and PSU you're looking at closer to 300 + whatever boxes you put it in.

The group buy/build thread is here. http://www.diyaudio.com/forums/analo...-builders.html

[sq225917]

Well after much being sat around on my arse doing nothing i finally got round to boxing this up today. I did one channel this afternoon and I'll do the other one tomorrow. I'm not normally this neat but the idea is that this is my last phonostage, (well last design, I have another set of pcb's waiting to be filled with primo parts).

Anyway here's the two shots, inside and outside.




Just the final earth path to sort out...

[337alant]

Beautiful job that Simon , looks like it will have to be a 3 box job.
Its a pity that heat sink is so high or it may have been possible to stack them in one case which is what I wanted to do.
Alan

[sq225917]

With one channel in each box they run pretty cool and there's no temp cycling or pumping of the input stage transistors from the heat from the other channel. Each channel may run a different temps due to the shunt reg.

[sq225917]

Well that was so good I'm going to do it all again, this time with transistors all matched to better than 1% and using 0.1% resistors and similar matching for all the small signal caps. I also have a selection of much better simulating transistors to use for all the main parts of the servo and some genuine 2sk170's.

I also fancy dropping the 2x5 transistors on the input stage on each channel under the PCB and heatsinking them all together with copper bus bar.

[YNWaN]

Well, it looks like I will have the opportunity to audition this very phonostage in my own system tonight (when Si brings it round).

Must say, I've got slightly mixed feelings. On the one hand I'm eager to extend my experience; on the other hand, if I really like it I will want one...

It will be up against my own humble stage - a DIY creation based on Naim 323 cards. Up to now it has seen off all that it has been compared to.

[YNWaN]

I've just finished listening to sq's 'home built' phonostage and I have to say, it is a remarkable bit of kit. In many ways it sounds just as my own phono stage.

Initially we listened to the first XX album. On my phonostage it was a quite remarkable experience - starting with enormous reverb on voices and huge echo on instruments followed by super punchy DC type bass - I don't think either of us felt it lacked for anything! A quick swap to sq's stage and the sound was, if possible, even more subtly nuanced, with perhaps a hint of emphasis to leading edges. For me, bass was even drier with better delineation - actual extension and weight was just as good. Swapping back again, my stage had a velvety quality that was missing from sq's - however, whilst it was all there (information wise), I did miss the leading edge detail that sq's stage delivered.

It's not an easy comparison, in isolation you listen to my own stage and nothing seems missing,timing is strongly projected, dynamic range is huge, frequency extremes are solid and extended, yet the sound isn't forced or trying too hard.

I think....sq's stage brought a level of subtle sophistication that was previously, in comparison, missing -better leading edge, slightly better tonal colour and a more consistent quality right in to the deep bass.

Any way, I've got sq's stage for a few days - so we shall see...