Pass B1

[kanwar]

See JFETs are very linear devices and its fairly easy to construct a balanced in/out stage from just 7 devices, compared to 4 devices in my first option. In this way you also have option either to use feedback or not.

 

[denom]

Sachu/Om,

Is the Balanced In/Out option do able??? Would be obliged if you guys shed some light as Kanwar has, will make my life easier, as plan to use the B1 pre with Active Speakers having XLR connectors.
Thanks

 

[omishra]

Sachu/Om,

Is the Balanced In/Out option do able??? Would be obliged if you guys shed some light as Kanwar has, will make my life easier, as plan to use the B1 pre with Active Speakers having XLR connectors.
Thanks

Though it can be done, it could not be with pass b1 kit. For that new input output design will be required. I got what he is telling. It's differential input with common current source. Is that correct?

 

[anilva]

Is there a way to make the B1 output 'balanced' from the existing 'unbalanced'

Rajesh,

Don't bother about this. I have used Behringer with Balanced and unbalanced. Does not make a difference for normal domestic use. Balanced is good for long cable runs.

Tinkering with Nelson Pass's design to add or subtract anything by ourselves will defeat the purpose of such a good design and probably alter the sound character, even if it means adding few more jFets.

Cheers.

 

[atharva]

Any update on the cabinet? Are we waiting for Bibin's quote? Also, I don't think we heard from Magma.

 

[bibin3210]

Any update on the cabinet? Are we waiting for Bibin's quote? Also, I don't think we heard from Magma.

Please see this

http://www.hifivision.com/diy/27797-diy-enclosure-cabinet-poweramp-preamp-6.html#post446510

Thanks,
Bibin

 

[omishra]

Possible! But I know it using additional OPAMP stages. Need to look if it could change /add harmonic character of sound. Balanced IC helps noise cancellation where common mode noise induced from surrounding. I feel small length interconnect with good quality shield could be unbalanced when signal level is line level.

Do you have special requirement in mind?

Though it can be done, it could not be with pass b1 kit. For that new input output design will be required. I got what he is telling. It's differential input with common current source. Is that correct?

Rajesh,

Don't bother about this. I have used Behringer with Balanced and unbalanced. Does not make a difference for normal domestic use. Balanced is good for long cable runs.

Tinkering with Nelson Pass's design to add or subtract anything by ourselves will defeat the purpose of such a good design and probably alter the sound character, even if it means adding few more jFets.

Cheers.

Thanks Anil, that strengthens my point. I am hesitant to unnecessarily add complex design to fairly simple no feedback buffer. Differential preamp will not be 100% transparant as original Pass B1 irrespective of what you use to construct it - OPAMP, discrete JFets or BJTs.

 

[atharva]

Thanks Bibin. What is the price (I didn't see it in the thread)?

Questions for the gurus.

1. I plan to feed the pre-amp with my DIY DAC but I have 3 sources. What is the best way to switch between 3-4 optical/coax inputs? One option was to convert optical to coax and then use 4-input switcher suggested for pre-amp (if possible). Is there any loss of quality from optical to coax?

2. I see that Om's cab was 12" while Bibin's is 17". If Bibin's cab has space can I move the DAC into the same cab as the pre-amp without impacting sound quality?

 

[captrajesh]

I have used Behringer with Balanced and unbalanced. Does not make a difference for normal domestic use. Balanced is good for long cable runs.

Yeah, that was running in the back of my mind.

Tinkering with Nelson Pass's design to add or subtract anything by ourselves will defeat the purpose of such a good design and probably alter the sound character

That is a valid point Anilji I'll surely buy that.:thumbsup:

 

[bibin3210]

DIY Tools and Components

Tools
1. Soldering Iron
Soldron - 25W Soldering Iron

2. Soldering Flux
Soldering Flux

3. Wire Stripper/Cutter
Wire Cutters / Strippers

4. Digital Multimeter
LCR Meter
UNI-T33D Digital Multimeter

5. Desoldering Pump (Metal)
MX Desoldering Pump - Metal Body

6. Soldron Soldering Iron Tip
Soldron - Soldering Iron Bit

7. Soldering Iron Stand
Soldron - Soldering Iron Stand

Components
1. Nuts and bolts/Screws
Screws

2. Spacer (SS)
Spacer - 5mm SS

3. RCA Female Panel mount (Gold Plated)
MX RCA CONNECTOR CHASSIS (GOLD PLATED) - PAIR

4. RCA Male (Gold Plated)
MX RCA CONNECTOR FULL METAL WITH SPRING (GOLD PLATED) - BLACK
MX RCA CONNECTOR FULL METAL WITH SPRING (GOLD PLATED) - RED

5. Power Jack Chassis Mount with 10A Fuse Holder
Elcom - Power Jack Chassis Mount with 10A Fuse Holder

6. Power cord
AC Power Cord Black

7. Switch - Source selector(Rotary)
Rotary Switch 1 Pole 12 Position Non-Shorting

Thanks,
Bibin

 

[omishra]

DIY Tools and Components

Tools
1. Soldering Iron
Soldron - 25W Soldering Iron

2. Soldering Flux
Soldering Flux

3. Wire Stripper/Cutter
Wire Cutters / Strippers

4. Digital Multimeter
LCR Meter
UNI-T33D Digital Multimeter

5. Desoldering Pump (Metal)
MX Desoldering Pump - Metal Body

6. Soldron Soldering Iron Tip
Soldron - Soldering Iron Bit

7. Soldering Iron Stand
Soldron - Soldering Iron Stand

Components
1. Nuts and bolts/Screws
Screws

2. Spacer (SS)
Spacer - 5mm SS

3. RCA Female Panel mount (Gold Plated)
MX RCA CONNECTOR CHASSIS (GOLD PLATED) - PAIR

4. RCA Male (Gold Plated)
MX RCA CONNECTOR FULL METAL WITH SPRING (GOLD PLATED) - BLACK
MX RCA CONNECTOR FULL METAL WITH SPRING (GOLD PLATED) - RED

5. Power Jack Chassis Mount with 10A Fuse Holder
Elcom - Power Jack Chassis Mount with 10A Fuse Holder

6. Power cord
AC Power Cord Black

7. Switch - Source selector(Rotary)
Rotary Switch 1 Pole 12 Position Non-Shorting

Thanks,
Bibin

Also add de soldering wick into list another 15Rs cost but help a lot. Because not everybody is expert of using de soldering pump.

 

[bibin3210]

Also add de soldering wick into list another 15Rs cost but help a lot. Because not everybody is expert of using de soldering pump.

Sure i will add that and update this list.

Thanks,
Bibin

 

[apk]

If you can add a power on/off switch also, that would be great.

 

[atharva]

Gurus,

Any suggestions on my question about DAC input switching and fitting inside same cab?

 

[bijinmb]

yes, will be adding the power switch as well in the list either of Elcom or MX make.

 

[denom]

On the Vol Pot front, howz this?


Original Japan Alps Quad Potentiometer RK27 Blue Velvet 5K O 10K Pots RK27114 | eBay

 

[sachu888]

On the Vol Pot front, howz this?


Original Japan Alps Quad Potentiometer RK27 Blue Velvet 5K O 10K Pots RK27114 | eBay

It looks good, but 10k could be too low fr B1.BTW all parts have been ordered for B1 and Power supply.

Regards,
Sachin

 

[apk]

BTW all parts have been ordered for B1 and Power supply.

Regards,
Sachin

This is good news Sachin. Any idea when you will be receiving the parts?

Thanks.

 

[Audiodoc]

@ Sachin. Please tell me how much I have to pay for a pair of sk170s matched. My pass BOZ is ready just have to insert the transistors.

 

[sachu888]

@ Sachin. Please tell me how much I have to pay for a pair of sk170s matched. My pass BOZ is ready just have to insert the transistors.

Hi Doc,
I will Pm you when I receive them.Spencer has shipped them but there could be a delay due to X-mus.

Regards,
Sachin