GK-1 - Stage 2

Malcolm Fear · « **on:** 25 Jan 2003, 10:48 am »

I have been fortunate enough to be one of the first beta testers for the stage 2 of the GK-1.
The Stage 2 is an input selector and phono stage.
It took me a while to get it going. For the extra few bucks, I bought "swish" capacitors and resistors from Welbourne Labs for the RIAA network.
Got it all going and working.
I remember buying "Running On Empty" by Jackson Browne (on vinyl) back in 77 (perhaps 78). BTW, Jackson is touring in February in Australia.
It has always been a fantastic record. It was the first live record released that I know of, that was not a just live rehash of hits.
There is one track (Track 2 - The Road), where the first part of the song is recorded in a motel room, and the remainder is recorded at a concert (very clever).
The section that is recorded in a motel, has an open window. Once upon a time (on very expensive Audio Research gear), one could hear a cricket, chirping outside the window (to the right).
I have missed that cricket for the last 20 years.
Tonight, using the phono section of stage 2, the cricket has returned.
Let me say that the stage 2 for the GK-1 is fantastic. I normally use a DACT volume (stepped attenuator) and a DACT selector switch. I still like the DACT volume, but the switch supplied with the stage 2, is the equal of the DACT selector.
The phono stage is magnificent. I have been playing Peggy Lee (from the 50's), Little Feat (The live concert (Waiting For Columbus) on Mobile Fidelity), Just One Night - Eric Clapton at Budokan from 1980.
The damn thing is every bit as good as the GK-1 -- stage 1. I am getting the soundstage I get with CD's. I am getting height (a GK-1 strength).
Another aspect is the way in which scratches, clicks and plops are dealt with. They are very subdued in comparison to other phono stages that I have used.

Well done Hugh!

U4EA · « **Reply #1 on:** 25 Jan 2003, 07:52 pm »

Don't they play cricket in Oz? Perhaps that is why you can only hear it on the AKSA?

I actually started looking for the cricket in my apartment the day I bought that album.

Johnny · « **Reply #2 on:** 27 Jan 2003, 04:06 pm »

Quote from: Malcolm Fear

Another aspect is the way in which scratches, clicks and plops are dealt with. They are very subdued in comparison to other phono stages that I have used.
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Good to hear positive feedback on the GK phono stage.
How would a phono stage "deal" with clicks and pops. Is there filtering or intentional design? It seems that an accurate and revelatory phono stage would pass these transients just as well.

As Brar Rabbit said when told that a thermos can keep liquids hot or cold-
"How do it know!?"

Thanks
Jy

SamL · « **Reply #3 on:** 27 Jan 2003, 11:12 pm »

Hi Malcolm,

Don't mind I ask you some off topic questions.
Are you still using the 8 strands cat5 cable? Is it 4 strands for the "+" and 4 strainds for the "-"? How long is your cable and have you try 12 strands.

I have 80ft of teflon insulated cat5 and thinking of making something with them.

TIA,
Sam

Malcolm Fear · « **Reply #4 on:** 28 Jan 2003, 01:17 am »

Hi Sam
I use 8 strands for speaker leads, four coloured for positive, 4 white for negative. My speaker leads are about 6 feet. I use 16 ohm speakers. It all sounds great. I started with 4 strands, went to 8, went to 16 and it sounded awful, so went back to 8. A friend uses an AKSA power amp and Ambience ribbon speakers (I think they can be around 4 to 6 ohm load). He found that 8 strands was best for him. He has about 9 feet leads.

regards

SamL · « **Reply #5 on:** 28 Jan 2003, 01:55 am »

Thanks Malcolm,
That mean I will have more left over.

Sam

Malcolm Fear · « **Reply #6 on:** 28 Jan 2003, 09:59 am »

Hello Johnny.
I was hoping Hugh would run with this question.
>>Clicks and plops!
I don't really know why a phono stage would make the clicks and plops disappear to a greater degree. Maybe there is something in the design that is very stable. Some phono stages can ring at high frequencies, accentuating the clicks and plops. Maybe Hugh's design doesn't ring.

Remember 30 years ago, when we all had to buy direct drive turntables? Light flimsy aluminium platters, with rubber ringed mats? If you measured them after 24 hours, they would have completed 48000 revolutions (can't get any more accurate than that), but the servo assisted feature dictated that they would never run at 33 1/3 for two seconds. They always hunted.
Funny how a Linn Sondek measured worse, sounded better, and also got rid of a lot of clicks and plops. I believe the felt mat and heavy platter absorbed the ringing effects of clicks and plops.

AKSA · « **Reply #7 on:** 28 Jan 2003, 10:59 am »

Malcolm,

I'll leave the clicks and plops alone until I've had a good think about it.

I suspect there are two issues here, however.

The equalization on the GK-1 phono circuit is a mixture of feedback and passive, and the passive section, on the output, has huge rolloff at very high frequencies. This will tend to shunt the sharp transients of clicks and plops to ground.

In turn this requires a very low output impedance from the chip, and this chip can do it with ease.

I have to say I'm very happy with the results; this is a very good circuit, meeting my demands for high performance, moderate cost, and simplicity.

Cheers,

Hugh (presently working feverishly on the pcb design for the GK-1 digital remote!!)

EchiDna · « **Reply #8 on:** 28 Jan 2003, 11:10 am »

Quote from: AKSA

*snip*
Cheers,

Hugh (presently working feverishly on the pcb design for the GK-1 digital remote!!)

your legs must be huge with all the pedalling Hugh