Phono Cartridge Loading

[Lee S]

Hi Gerry.

I have silicon in the arm. 600,000 Ct/St. It's so thick, the arm takes two seconds to drop from an inch onto the vinyl. This is how the Gray is meant to be. It's great... Who needs armlifts?

Fortunately the damping is adjustable using the threaded pivot well. I have tried full damping to no damping and it has very little effect on the bass. It definitely improves imaging, focus and tracking but does very little to the bass of this cartridge.

I will have a go with the SUs at 1:20. That's the last thing to try really. I have tried everything else, other than waiting for it to run in. I know you should really give carts 20-50 hours to settle down. It does seem to be getting better today. Less lean than yesterday.

Fingers crossed it will get a whole lot better.

It think the bass is there and it is very good quality and detailed, textured and tuneful, but it is very low amplitude. It's almost as though it is being drowned out by the mids and highs. Unbalanced - as though the bass could do with more drive.

Will report back with the results of the SU change.... soon!!

Cheers

[Gerry]

Lee

What you describe is the right sort of bass with damping. The fullness I was talking about may well be due to the VTA.

There are those that don't believe VTA makes a difference to the 103 sound (a whole web page dedicated to it on TNT!). iI beg to differ with them as I feel it makes a huge difference.
If you haven't played with the VTA, this is where I would start. Lower the back of the cartridge and work up. (I'm sure you've done this and don't mean to teach Grandmother how to suck eggs!)
Too high on the back gives a very treble mid range emphasized sound.

Good luck.
Regards
Gerry

[Lee S]

Not at all Gerry. Any help gratefully accepted.

Just gone to 1:20. Burned my finger on the soldering iron. Had enough of soldering for one day now!! Grrrr...

Seems no different at all other than more gain obviously, so less volume dialled in. Not sure I like the idea of that. I may change back again at a later date.. or not.

Funnily enough, VTA is the only thing I have not played with Gerry. Looking at the cart from the side now, it does have its arse in the air a little. I will temporarily remove the levelling nuts from the arm and get the back right down. See what that does. I must admit that I was in the camp of "spherical stylus - VTA does very little if nothing", but as ever, I shall bow to others experience and give it a go.

Thanks all

[Lee S]

Oooohhh!!! That's a bit better.

Bit more bottom end now that the cart is level with the record. Dropped the back of the arm by about 6 or 7 mm by removing the knurled levelling nuts. Sounds nice now. It seems to have reduced what little shoutiness and glare there was too. Smoother presentations. Surface noise has been reduced a tad also. I think I could live with this now. Great stuff.

I have had enough for tonight, so I am going to realign the cart/arm (the flamin' base moved slightly whilst removing the nuts) and sit back and listen for a few weeks now. Get some more hours on it.

Cheers

[Andrew]

Lee

What you describe is the right sort of bass with damping. The fullness I was talking about may well be due to the VTA.

There are those that don't believe VTA makes a difference to the 103 sound a whole web page dedicated to it on TNT!).
Gerry

Well spotted, Gerry, I knew there was something else to this.......

cheers,

-- Andrew

[Dave the bass]

Ta for the invite to merge threads Lee,

Right, just to back-track a bit....

I've got a cheapo all valve 'Lite Audio' Phono amp, it has i/p's for MM and MC, using MC with a 103 is noisy sooooooooo I've had to revert to using the MM i/p, Philip has kindly lent me his Denon AU-300 LC step ups (1:10). The SU is now loaded with 100R across the primary (across the phono leads that connect TT to SU actually as the SU's aren't mine I don't want to open them up being a Gentleman 'n' all that). The 47K 'MM' loading resistor is switched out of the signal path (all the loading resistors are switchable see here if you're interested http://www.tommytube.com/dunkin/LS37.pdf )

I've got (conveniently) the existing 1M (R6/106) in place still, that's acting as the secondary load yes?.

Testing tonight shows a tad more mid-top information to my ears, I like it, it's not glaring or nowt just a bit more 'there'. I'm crap at describing things!

What shall I play with next?

And more importantly what the bleedin' heck am I actually doing ? Seriously, I know Andrew and Nick went into this in but in simple DTB terms what are we actually doing to the cct and the sounds here, can anyone tell me? Ta if ye can!

DTB

[Gerry]

Lee

Glad it's an improvement...sounds as if you're getting there. Don't be afraid to drop the rear a little, so that it is not a parallel. Se if you like it. it can result in boomy bass. There is defiantly a sweet spot with these cartridges. The sound will improve as the cartridge breaks in.

Regards
Gerry

[Lee S]

Thanks Gerry.

I will have a mess around with loading again in a couple of weeks when she's run in a bit more. I am going to have to get off my backside and build a plinth for the GL88. I will recess the arm board so that I have a bit more adjustment on the VTA. It actually looks like it could go down another few mm, but I have no more adjustment. The arm plate is flat on the plinth. Something to sort out after the amp is built anyway.

Cheers

[Gerry]

Dave

The 100R on the primary suits the 103R better than the 103, Andrew is far more knowledgeable than me on this. He has suggested something higher say 500R. I'd give this a try fist and then move down.
If the primary is loaded, ideally the 47K resistor on the phono (secondary) should be removed and replaced with a 1M.
I'm not sure if your switching the 47k out has the same effect, I could be wrong.

As for why it works...I'm not really sure...Andrew's or NickG are your men on this.

Regards
Gerry

[Andrew]

OK, here goes, as I understand it, transformers are not perfect devices, they have losses in them.

The current theory is that the transformer's parasitics contain enough capacitance and other nasties to react with the large resistive load on the secondary to form a low pass filter - approximating a 3rd order filter.

So, even if you can't hear the roll off directly, it causes slew rate limiting and loss of treble resolution/energy. Of course, the nasties get reflected across the windings which further complicates things.

The resistive load on the primary is much much smaller, for the same loading effect, so it has less impact on the filter. Put another way, its still there but its moved out of range and the 3db point is much higher.

The concept is simple but when you think about real work "imperfect" transformers, then you need to get the asprin out. After all do *they* know which is primary and which is secondary?

This whole effect is worse for a high Z out cart like the 103 since it adds to the problem by further lowering the 3db point since it is less able to drive the step ups.

Right I'm off for the asprin.

cheers,

-- Andrew

[Clive]

Which as Andrew knows is why I'm building the Hagermann Piccolo head amp. I don't know if it will be better than my TX-103 SUTs but it's not too expensive to build and I have to know.....

I should have the answer sometime next week, the first parts have arrived.

http://www.hagtech.com/piccolo.html
I'm doing the half kit.

[Dave the bass]

Dave

The 100R on the primary suits the 103R better than the 103, Andrew is far more knowledgeable than me on this. He has suggested something higher say 500R. I'd give this a try fist and then move down.
If the primary is loaded, ideally the 47K resistor on the phono (secondary) should be removed and replaced with a 1M.
I'm not sure if your switching the 47k out has the same effect, I could be wrong.

As for why it works...I'm not really sure...Andrew's or NickG are your men on this.

Regards
Gerry

Thanks for the tip Gerry,
Trying other resistors is super easy for me, OK I'll try a 510R or so and see what differences there are.

Looking at the cct diagram you can see that when I switch out the 47K all thats left is the 1M (between ground and Grid) that the 47K was in parallel with. If I replace the 47K with another 1M I'll be lowering the secondary to 500K won't I (?) which give a reflected load back through the TX of 50R I think.

Andrew,

Many thanks for the explanation, I'll try and get my grey cells around what you're saying.

You're all very nice chaps.

DTB

[Dave the bass]

Clive, is the project you're building described as a 'head amp'? It takes place of the SU TX I'm guessing yes?

DTB

[Lee S]

Well I'll go to the foot of our stairs. I think you've cracked it Gerry, old boy!! Got quite a bit more bass now. Just having a flick through some fave albums and it seems to have improved it no end. It may improve further with time too. Cool!!!

It is sounding good now. I think I like the 1:20 too. It sounds less "forced" than the 1:10 for some reason. Maybe it is a result of the VTA being lowered though. I will revert to 1:10 again later just to make sure. I like it though!! Just listening to "Soulmining" The The, "Seven Singles Deep" Icicle Works, bit of Peggy Lee, Billie Holiday, Suzanne Vega, Jon and Vangelis, etc etc... Time to crack open some more albums... He He.

Not bad at all for £82 !!!



PS: Everyone seems to be going to the foot of their stairs tonight !!

[simon]

Steady Lee, you'll have the 103 police calling on you in the middle of the night