Pass B1

[sachu888]

You'll find more info. on part selection, options and BOMs here:

Nelson Pass B-1 preamp kit

Thanks Grubyhalo,
I have already posted this on my first post of this thread.Salas said no for gerber files of his version,coz there is a group buy on DIYA store.

Regards,
Sachin

 

[grubyhalo]

Oops sorry, didn't quite notice it. I personally think it wouldn't be too expensive of a deal to do a bulk-buy from the DIYA sale...

 

[sachu888]

Oops sorry, didn't quite notice it. I personally think it wouldn't be too expensive of a deal to do a bulk-buy from the DIYA sale...

Good suggestion from buying from DIYA but Pass PCBs are costly $54 with shipping.

Regards,
Sachin

 

[jetlag]

At $54 it is expensive, but then the quality would be great. And yes, I too need a 50K pot.
Jetlag

 

[captrajesh]

Salas said no for gerber files of his version,coz there is a group buy on DIYA store.

When I was actively considering to go the DIY route, I was thinking of making this as well as F5. I have downloaded the Gerber file from PassDIY site sometime back. I can share it if required.

And, I too am in for a kit.

 

[gobble]

When I was actively considering to go the DIY route, I was thinking of making this as well as F5. I have downloaded the Gerber file from PassDIY site sometime back. I can share it if required.

And, I too am in for a kit.

The pass pcb is avaialble on the order form. The Salas shunt regulator is the one that is not shared.

-G0bble

 

[sachu888]

At $54 it is expensive, but then the quality would be great. And yes, I too need a 50K pot.
Jetlag

Hi,
There are two version of B1
1. Nelson pass(original)PCB $54 with matched Jfets,including shipping
2.Salas PCB $18+shipping

I have gerber files of original B1 and PCBs can be made locally within RS 250/PCB.I have found out a source for matched JFETs in DIY audio($2/pair+ shipping).Most of the components are available with Element14 Indian website,only few have to be sourced from Digikey/part connection etc.Total cost would be around Rs 2000 minus enclosure.

Regards,
Sachin

 

[grubyhalo]

At about $20 a pop, the board on sale at DIYA would seem the best option considering that it is the DC coupled version with the Salas reg's built-in. The original Pass version would not be DC coupled nor have the regulators built-in. Just my 0.02...

 

[omishra]

It need power isnt it?, so active enough for me. Atleast that is what we were taught,it is been more than a decade so i am a bit rusty

Sir jee, Its active circuit with passive role in terms of amplification and phase changes in audio [frequency band].

It just matches impedance by making constant high input impedance and 50ohm output impedance. So all signals at input are handled well at high input impedance. Otherwise they are at mercy of volume pot if connected directly to it.

For input select what you say about this 4-1 select?

For both of below configs, TT input goes through CNC phono and then to above input selector.
Config 1: All input except TT goes to source selector first. From here it moves to Volume control of this kind of 50Kohm. From there it is fed to this preamp buffer module which will give it to output.
Config 2: All input except TT goes to source selector first and then selected output goes to this preamp. From here it moves to Volume control of this kind of 50Kohm. From then fed to this preamp again. Here it goes to output after second stage.

Volume control is this.

I am inclined towards config 2. I want to dismantle this old item with me to get parts and put them in new bigger box with new friends, CNC phono stage, PASS B1 and power supply regulators. Power supply transformer will be at wall adapter and get 3 wires to box and put PS, regulators inside box. Use XLR type connectors at metal box for PS.

What do you say?

 

[stereorules]

I would also be interested ...But need some clarification ..This is a GB for only the preamp PCB and parts ? or is an input selector + pot also included ?
Another silly question ....Why cant I just hv an input selector going to a vol pot and then to a power amp ?

 

[omishra]

....Why cant I just hv an input selector going to a vol pot and then to a power amp ?

Yes this also works, I was using it same way, see this.

Only problem comes as you feed your power amplifier with variable resistance that changes impedance with volume level. If you have signal source with high output impedance which could not be handled at that power amplifier (due to low input impedance ) then it tries to load source. Affects sound quality by means of distortion.

Input impedance should be very large (ideally infinite), practically we have 10K-100K in power amplifiers. This buffer provides multiple of mega ohms far more than required.

Also output impedance should be very low (ideally zero), practically we agree 50-500 ohms for pre amps. Here this buffer offers constant 50 ohms output impedance. As I stated earlier volume control is variable resistor. From its output side towards amplifier it changes value wrt volume level.

So using it at lower value than amplifier's input impedance adds distortion as lower volume levels too. It may be audible or not.

Please look here for more information.

 

[sachu888]

I would also be interested ...But need some clarification ..This is a GB for only the preamp PCB and parts ? or is an input selector + pot also included ?
Another silly question ....Why cant I just hv an input selector going to a vol pot and then to a power amp ?

Hi,
This GB is for Pass B1 PCBs(can be made locally) and parts.

Regards,
Sachin

 

[sachu888]

Hi all,
Following members have shown interest in Pass B1
1.Capt Rajesh
2.Omishra
3.Prasad(Quad)
4.Gobble
5.Jetleg
6. Sachin

PLease let me now if I missed someone.

Regards,
Sachin

 

[sachu888]

Hi,
I have found most of B1 parts on Element14 Indian site :

Shopping Basket | element14 India

Regards,
Sachin

 

[santhosh]

Please count me in Sachin.

 

[sachu888]

Please count me in Sachin.

Added

Regards,
Sachin

 

[quad]

Hi Sachin,

After some consideration, I would like to withdraw from this
group buy as I have other pending projects.
I am considering modding my diy pre with a tube based buffer at
a later stage, if/when needed.
Regret any inconvenience.

Thanks
Prasad

 

[sachu888]

Hi Sachin,

After some consideration, I would like to withdraw from this
group buy as I have other pending projects.
I am considering modding my diy pre with a tube based buffer at
a later stage, if/when needed.
Regret any inconvenience.

Thanks
Prasad

Hi Prasad,
No problem,

Regards,
Sachin

 

[omishra]

Hi Sachin,

Please count me for 2 kits. I would like to add it before and after volume control.

BTW, how you search the part number on this site. I am pissed off with huge list as result of search.

Regards

 

[stereorules]

Hi all,
Following members have shown interest in Pass B1
1

PLease let me now if I missed someone.

missed me ...Pl add me also .