The final part of the trilogy - Phonostages

[northwest]

Following my successful turntable and tone arm threads, I bring you the last part in this trilogy, Phonostages?
I am going to be running an SME arm through a croft micro 25 pre with MM phonostagecand out to a Quad 303 power amp. Do I need (and that's the operative word here, need) a phonostage?
I have seen a few DIY examples that interest me and I quite fancy having a go as it will be a modest outlay.
Thanks.

[YNWaN]

Well, you already have a phonostage, a MM one built into your Croft. I don't really know the Croft, but I wouldn't assume it will necessarily be bettered by an external design. The main advantage to making the phonostage external is that it no longer shares the pre-amps power supply which makes things better for the pre-amp and the phonostage now has its own power supply - but this benefit only works if the designs involved actually benefit from power supply alterations of this sort - this is certainly not guaranteed.

If you want to have fun making a kit, that's a different matter :).

[northwest]

Well, you already have a phonostage, a MM one built into your Croft. I don't really know the Croft, but I wouldn't assume it will necessarily be bettered by an external design. The main advantage to making the phonostage external is that it no longer shares the pre-amps power supply which makes things better for the pre-amp and the phonostage now has its own power supply - but this benefit only works if the designs involved actually benefit from power supply alterations of this sort - this is certainly not guaranteed.

If you want to have fun making a kit, that's a different matter :).

I must say, I am extremely tempted to build a phonostage. I realise the croft mm stage is a first class stage but yes, I am interested in building a phonostage of my own.

[YNWaN]

Do it then :) - I think you will find if fun and very interesting.

[northwest]

Do it then :) - I think you will find if fun and very interesting.

I shall Mark, I was just wondering if anyone has any experience of the self build phono stages? All suggestions welcome.

[WOStantonCS100]

My main phono stage for about 2-3 years now has been a DIY Bottlehead Seduction (without the upgrade... haven't felt it necessary as of yet) running on EH 6922's :(; not always the greatest valves... read on.

I've had a little bit of noise (-45dB to -50dB) on the left channel. On my analog recorders the noise doesn't even show; but, on digital recorders it does. If I cranked the volume I could hear it; not hum, just noise. Since, I now swap in a 681EEE (output in the 2.5mV range??) the noise was more apparent than when using carts with twice the output or better. I thought I had ruled out the valves a long time ago and just hadn't gotten around to figuring out where it was coming from. Well, last Sunday I finally had enough. I bent resistor and cap leads and tilted things this way and that, even tried better internal shielding.

Long story, short... I swapped valves again and watched the meters. :doh: It was the frikkin' valve all along!!! Needless to say, I've ordered (a few) replacement valves. Sheeesh.

The thing to note, I guess, is that I like the sound so much better than what I had been using that I was not willing to pitch the Seduction for the sake of a little noise. Of course, now with another quiet valve on the left channel, I'll have a pretty musical and quiet phono stage. The C4S upgrade is supposed to improve on the stock version in all ways; but, I'm still very content with it as is.

It's just one of many DIY options that will wipe the floor with many lesser entries. I can't speak to the others as I have not built any others. But, geeez, if it's valve based... spend the money on some good valves... otherwise it's an exercise in futility. If they're new production valves, you may have to go through a few to find the good ones.

Hope some of this was helpful. Good Luck!!

[AlfaGTV]

Not for everyone, but some people swear by Lundahl trannies to get your MC voltages up to suitable for MM input?

Perhaps to easy, considering the DIY ambition?

BR /Mike

[northwest]

Not for everyone, but some people swear by Lundahl trannies to get your MC voltages up to suitable for MM input?
Perhaps to easy, considering the DIY ambition?
BR /Mike

With respect Mike, I am only going to use valves, I like valves. Here for instance are a couple I nailed together last month:

http://immersible.co.uk/images/nixie.JPG

[AlfaGTV]

:) No probs!

By the way, is that one of those new "analogue DAC's" i keep hearing about?
:lol: :eek:

BR /Mike

[DSJR]

The great thing is that you have a pretty well reference grade phono stage in the Croft to refer back to with your other projects - it's that good. The RIAA is within half a db or better, the overload more than good enough for the peakiest Decca's and it's quiet enough for most jobs it's asked to do. I keep my old AVI preamp as a reference, so for example, when I was bodging up the Crown IC150 recently, I used both my Croft and AVI as a reference - the AVI is extremely good and utterly faithful to the source fed it, but so is the Croft, with that tiny bit of "something extra" that makes me want to listen through it for hours, given half the chance. I've been able to economically get the IC150 to do the same for me and can only suspect that the bad press it received in the US in the 80's was because of the severely coloured rose tinted valvey processor jobs masquerading as preamps made by so called top end manufacturers back then (yes ARC and CJ, I mean you lot!!!!!:()

By all means make your own phono stage. It'll be huge fun and PLEASE keep us posted on how you get on - loads of piccies please too :)

[northwest]

:) No probs!

By the way, is that one of those new "analogue DAC's" i keep hearing about?
:lol: :eek:

BR /Mike

Very good!:lol:

For those that don't know it's a Nixie clock, because it uses Nixie Tubes:eyebrows:
My son bought it for my birthday and I finally had a chance to put it all together last month. The missus loves it so at least one brownie point, it tells the date and has an alarm function too. Bought all the bits from http://www.pvelectronics.co.uk/index.php but the tubes keep going up in price as they are becoming scarce.

[WOStantonCS100]

... I am only going to use valves, I like valves...

I'm not sure I'd call myself a "purist"; but, one of the things that really drew me to the Bottlehead was the layout. It's all point-to-point hand-wiring with no IC's, no PCB's, (unless the upgrade is installed), no op-amps, nothing but a handful of wire, caps, resistors, diodes, a couple of valves, a fuse and a tranny.

In progress:

http://i815.photobucket.com/albums/zz80/TCKA1ESa/Projects/SED_2.jpg

Finished (top):

http://i815.photobucket.com/albums/zz80/TCKA1ESa/Projects/IMG_5056.jpg

Finished (underneath) from their website:

http://www.bottlehead.com/et/adobespc/Seduction/underside.jpg

I looked at the Audio Note L3 kit, as well; but, the PCB's put me off a bit (though I like the layout). It probably sounds excellent, also. I can't confirm.

[jostber]

The Hagerman Cornet is also an option for a phonostage kit that sounds great:

http://www.hagtech.com/cornet2.html

http://www.hagtech.com/images/largecornet2.jpg

[WOStantonCS100]

The Hagerman Cornet is also an option for a phonostage kit that sounds great...

That's the other one I was trying to think of. I've heard plenty of good things about this one, too. If my eyes don't deceive me, I do like the idea of a mono switch.

Side Note: My replacement valves arrived today. I should have done that a long time ago. I knew better; but, was apparently just being lazy. These puppies are dang near silent, even with the input of my digital recorder cranked to 12dB past unity gain (meters don't budge). Mmmmm.... I didn't realize how much the old tubes were holding it back. I do now. :)