Kuartlotron Error Correcting Super Buffer

[spirovious]

Yes for sure most of the guys are again interested :lol:

So fast group buy?
I can easily smell that Joshua will start cooking some thing new project soon.:

 

[jls001]

Repositioned volume pot and wired up front panel power switch:

One downside is a gaping 10 mm hole on the left corner of front panel where the pot was. Need to find a way to cover it discreetly. Poor planning on my part :sad:

Nicely lit up:

I'll rewire the on-off switches at the back and front - the front switch needs to be placed before the one at the back, otherwise switching off the front switch doesn't kill the integral blue lamp on the front switch. But interestingly it stops the flow of power to the buffer circuit. The blue lamp is powered by 15V DC from the OPS board.

At very high volume without anything playing I hear noise when placing ear very close to speakers. It needs to be totally silent. Something is raising the noise floor, and that's not acceptable. Either my circuit board is picking up noise, or my grounding scheme is not clean enough. I'm thinking of implementing the 35A Bridge Rectifier ground isolation scheme. I have the parts, and there is enough free real estate in the cab to do it.

Also, Keith suggested a DC rejection scheme to be implemented in the input-output path. Need to find two CM chokes of about 27 mH from a discarded PC SMPS, or try rolling something on my own.

I can easily smell that Joshua will start cooking some thing new project soon.:

A major project is in the offing Fingers crossed:licklips: Hopefully I will be able to start it as soon as I finish helping build a DCB1 for a friend.

 

[omishra]

Nice one Joshua!
This design has high bandwidth and the transistors too go till 30MHz. Hence it can easily oscillate the mains 50Hz or anything from environment. Grounding and shielding is key.
Put some rubber grommet into that 10mm hole. Optionally extra 5mm dim led could be placed into it. [emoji6]

 

[sarith]

Using shielded single or dual core wire might reduce or even eliminate the noise I guess..

At very high volume without anything playing I hear noise when placing ear very close to speakers. It needs to be totally silent. Something is raising the noise floor, and that's not acceptable. Either my circuit board is picking up noise, or my grounding scheme is not clean enough.

 

[somakmaitra]

Hi
The boards are available pretty cheap
Dirt Cheap Dirty Boards
Any input on the boards ?
Regards
Somak

 

[mbhangui]

Let's start :clapping:

Regards
Sachin

Yup. Ready to run when you blow the whistle. Hope that will be soon hyeah:

 

[omishra]

Hi
The boards are available pretty cheap
Dirt Cheap Dirty Boards
Any input on the boards ?
Regards
Somak

Somak,
These are good compact boards. 2 mono will make one stereo pair. For stereo wiring and volume control, you have to manage wiring as well as mounting.

Cost wise - with shipping and customs, (if any) it will cost same to what we are trying to make. Group buy makes sense with atleast 10 participant in it.

Also we can't compete price rate and quality of China/HK sellers.

Regards,

 

[keith_correa]

One downside is a gaping 10 mm hole on the left corner of front panel where the pot was. Need to find a way to cover it discreetly. Poor planning on my part :sad:

Why don't you put in a 5 mm MDF faade over the existing front plate? Engraving on it is inexpensive and you can polish it with a stain which will look very nice.

 

[sachu888]

Somak,
These are good compact boards. 2 mono will make one stereo pair. For stereo wiring and volume control, you have to manage wiring as well as mounting.

Cost wise - with shipping and customs, (if any) it will cost same to what we are trying to make. Group buy makes sense with atleast 10 participant in it.

Also we can't compete price rate and quality of China/HK sellers.

Regards,

I know this website. The price is for 1.2mm thickness boards, whereas we get 1.6 mm boards as standard.

Regards
Sachin

 

[keith_correa]

If anyone is interested in a shunt regulator to be used in the PS for this buffer, this guy shrunk the Salas shunt regulator. PCB files are in his dropbox account linked in that thread.

 

[saheb11123]

I know this website. The price is for 1.2mm thickness boards, whereas we get 1.6 mm boards as standard.

Regards
Sachin

Will you be selling the pcbs or kits with parts?

 

[omishra]

Will you be selling the pcbs or kits with parts?

possible if we come together 10 People before rupee crash. Part are with8n 300rs.if brought now from element 14. But not sure about PCB cost. Add shipping and packing.

 

[avesbilal]

Can someone try to approximate the total cost inclusive of parts, board, shipping? Who is running the group buy?

 

[Anil kumar]

Dear Om & Sachin, count me in for group buy.


Regards,
Anil

 

[saheb11123]

If the parts are within 300rs and the board cost comes down to say 200 or 250 , which I dont think will exceed more than that. Then its a good deal to go forward

 

[sachu888]

It should be approx Rs 600 including all imported parts, PCB and shipping, minus volume pot.

Regards
Sachin

 

[ajeshkumarts]

It should be approx Rs 600 including all imported parts, PCB and shipping, minus volume pot.

Regards
Sachin

Sachin,

Please count me in

 

[keith_correa]

Om, can you please see if you could add a shunt regulator to the PCB? I'm sure that for a buffer/pre it will make a BIG difference. Even a simple one [maybe this or the Salas v1] is fine.

 

[mbhangui]

Sachin, count me in for the group buy

 

[TD150]

Sachin count me in.