Kuartlotron Error Correcting Super Buffer

[Nikhil]

I've observed something which Raghunadh confirmed on another K Buffer he is building at the moment.
When turning up the volume on the K Buffer past the 9 o clock level, there seems to be no change in volume beyond 11 o clock position .
Even up to the 1 o clock position and more.

The K buffer seemed to also lose a little composure as well with the sound getting a little ragged around the edges.
I backed it down to normal levels and it seemed to be okay. Has anyone else observed this?
Is this due to the unity gain design that it sort of runs out of steam after a certain point?

 

[manniraj]

I've observed something which Raghunadh confirmed on another K Buffer he is building at the moment.
When turning up the volume on the K Buffer past the 9 o clock level, there seems to be no change in volume beyond 11 o clock position .
Even up to the 1 o clock position and more.

The K buffer seemed to also lose a little composure as well with the sound getting a little ragged around the edges.
I backed it down to normal levels and it seemed to be okay. Has anyone else observed this?
Is this due to the unity gain design that it sort of runs out of steam after a certain point?

I did not feel this in my setup but could be because I use a SSP (Super simple preamp) along with the K Buffer. Somebody with a old B1 setup (replaced with K Buffer) using with SSP can check and confirm back.

 

[jls001]

This could be due to the value of potentiometer used. I believe yours' is 50K log. I use 20K log. When I tried 50K log (CITEC as well as ALPS), I did feel like there is lesser effect in volume when turning knob between approx 9 and 11 O'Clock (6 O'Clock being zero for me).

As far as I understand, the best match would be 10K log pot.

 

[Nikhil]

Thanks Josh. Can you recommend a supplier for the Alps pot?

 

[koushik]

Thanks Josh. Can you recommend a supplier for the Alps pot?

You can check here Welcome to RS Online

 

[jls001]

You could try this one too:

ALPHA RV16 Type Dual Potentiometer A20KX2

Or this, though value is not ideal (unfortunately he doesn't stock 10 or 20K log):

21 Step High Precision Step Potentiometer A50KX2

The same site sells ALPS too, though I can't vouch for genuineness (apparently there are lots of fake ALPS in the market, though I'm in no way implying that what this seller sells is fake - just a general heads up):

Latest Products - OCT 2015

 

[Nikhil]

Thanks again guys. Will look into something locally available if possible.
If not then will go the online route from those websites.

 

[jls001]

Do try and get the best quality pot you can since the pot lies in the signal path (in fact it is the first component the signal from the source encounters when it enters the Kuart buffer).

You can also try DACT-type stepped attenuators from eBay.com. They're made from carbon film surface mount precision resistors (very closely matches channels), are highly rated (many consider them better than ALPS RK27 series), and costs about $12 apiece (plus shipping and applicable duties). I use one of 20K log value but I would recommend 10K log. The product is like this (example):

21 Step High Precision Step Potentiometer A50KX2

EBay link:
Dact Type 21 Stepped Attenuator Volume 10K for Preamp | eBay

 

[manniraj]

Do try and get the best quality pot you can since the pot lies in the signal path (in fact it is the first component the signal from the source encounters when it enters the Kuart buffer).

You can also try DACT-type stepped attenuators from eBay.com. They're made from carbon film surface mount precision resistors (very closely matches channels), are highly rated (many consider them better than ALPS RK27 series), and costs about $12 apiece (plus shipping and applicable duties). I use one of 20K log value but I would recommend 10K log. The product is like this (example):

21 Step High Precision Step Potentiometer A50KX2

EBay link:
Dact Type 21 Stepped Attenuator Volume 10K for Preamp | eBay

They both look different and if the audiocrafts one as well works on the similar lines then cost wise it comes out fine as the ebay one is around $18 including shipping.

 

[sarathssca]

Can we use this buffer with +/-6 or +/-7v power supply?

 

[Nikhil]

Do try and get the best quality pot you can since the pot lies in the signal path (in fact it is the first component the signal from the source encounters when it enters the Kuart buffer).

...

Thanks again Joshua for the link.
I looked up the delivery time and it was 2-3 weeks.

Have ordered an Alpha 10K pot from Bibin/Bijin's DIYAudioCart instead
Alpha - Dual Gang Audio Taper 10K

 

[jls001]

Can we use this buffer with +/-6 or +/-7v power supply?

Keantoken recommends +/-10V.

 

[magma]

josh

your review is still pending on this buffer VS your DCB1 ( after the grounding and upgrades and ckt corrections )

next time we meet get the Kuart to my place
i would like to hear it too
before i take a call

 

[jls001]

josh

your review is still pending on this buffer VS your DCB1 ( after the grounding and upgrades and ckt corrections )

next time we meet get the Kuart to my place
i would like to hear it too
before i take a call

Please feel free to get it from Vivek. It's with him

At this point too many changes in my system so I want to stabilize the sound, and then think of any comparo. In fact I haven't even touched the IC and speaker cable you lent me to listen.

 

[jls001]

Have ordered an Alpha 10K pot from Bibin/Bijin's DIYAudioCart instead
Alpha - Dual Gang Audio Taper 10K

Looks good :thumbsup:

I would also like to try this soon. Thanks for the pointer.

 

[vivek_r]

My friend and I went to JLS' to hear his set up.

Initially, there was a tendency to chestiness - my friend who is particular about NOT damping took out all the damping which was there and the sound opened up really nicely.

We then tried out JLS's old preamp and Kuartlotron - the latter had a more open sound which we preferred but both were good and it is a matter of taste.

What is amazing is how musical and good JLS' system sounded without all the mega buck brand names - we listened to lots of music - jazz, classical and even female audiophile vocals (JLS - ugh, not for me even after a few beers ). Even the interconnects and cables were serious budget ones!

Many thanks JLS and lessons learned by me:

a) Kuartlotron works really well and currently using it very well with my Harbeth and Operetta - JLS - thanks for the loan.
b) Jungson makes music!
c) Overdamping speakers can lead to boxiness that sounds like bass! Try without and see resolution
d) There are many products that can bring musical satisfaction without the big bucks - though resale could be an issue.
e) Joey's pizza in Andheri is amazing!

Many thanks to JLS for his warmth and hospitality.

 

[keith_correa]

We then tried out JLS's old preamp.

Which was?

 

[dheerajin]

Which was?

I can guess DCB1

 

[jls001]

I can guess DCB1

Yes, that's right

 

[sarathssca]

My friend and I went to JLS' to hear his set up.

Initially, there was a tendency to chestiness - my friend who is particular about NOT damping took out all the damping which was there and the sound opened up really nicely.

We then tried out JLS's old preamp and Kuartlotron - the latter had a more open sound which we preferred but both were good and it is a matter of taste.

What is amazing is how musical and good JLS' system sounded without all the mega buck brand names - we listened to lots of music - jazz, classical and even female audiophile vocals (JLS - ugh, not for me even after a few beers ). Even the interconnects and cables were serious budget ones!

Many thanks JLS and lessons learned by me:

a) Kuartlotron works really well and currently using it very well with my Harbeth and Operetta - JLS - thanks for the loan.
b) Jungson makes music!
c) Overdamping speakers can lead to boxiness that sounds like bass! Try without and see resolution
d) There are many products that can bring musical satisfaction without the big bucks - though resale could be an issue.
e) Joey's pizza in Andheri is amazing!

Many thanks to JLS for his warmth and hospitality.

One doubt here.. what does it mean by taking out all the damping?