Pass B1

[apk]

Hi Gans,
You can start your DIY with Super Simple Preamp (SSP) and run it on batteries.We are there to help you.

Regards,
Sachin

+1 to that. I had never used a soldering iron in my life before. I was able to put together a perfectly working SSP in a days time with Sachin's and Omishra's help. In fact, they both went out of their way to help me out with the SSP build. Kudos to their DIY spirit and helpful nature.

Seeing threads like these gives me inspiration to get into DIY but I don't have a Lion's heart.:sad:

Go ahead buddy. Many of us are absolute noobs when it comes to DIY. But we have a wonderful bunch of people on this forum to help us and guide us. You will not go wrong by starting with the SSP.

Best,
APK

 

[sachu888]

Parts update

Hi all,
Received all remaining components for B1.I will ship B1 kits in next 2 days.

Regards,
Sachin

 

[nraghunadh]

Just Finished PassB1+LDR assembly. Quality is awesome and unbelievable for that price. Need to find good chassis to fit PWR+B1+CNC+LDR.
Many thanks to Sachin,Omisra and Quad.
Thanks
Raghu

 

[mbhangui]

Sachin, Today only I got the time to solder all the components (Pass B1, Power Supply, LDR volume control and SSP).

I am stuck on the LDR volume control. The LDR are labeled 98 (or 86), 89 or (68), 16 (or 91) and 30. Where do I solder these?

 

[kroyin]

Did anyone try the B1 with simple volume pot.
Well I have tried
--2 B1 & LDR together
--1 B1 & LDR
--1 B1, 1 SSA & LDR Together

But last few days its only the B1 + 2 mono pots & they sound the best.

Could be the Manali Hash Diwali gift

 

[omishra]

I am stuck on the LDR volume control. The LDR are labeled 98 (or 86), 89 or (68), 16 (or 91) and 30. Where do I solder these?

Wasn't bag marked with L1, R1 and L2, R2. They need to go in respective odd and even numbered position matching dot. Also let me know which GB batch was this and rounded number on the bags, I may have matching sheet somewhere for this. Last time me and Swapnil matched these.

PS: tried to call you, your phone is not reachable - getting message "This number is not in use"

 

[sachu888]

Sachin, Today only I got the time to solder all the components (Pass B1, Power Supply, LDR volume control and SSP).

I am stuck on the LDR volume control. The LDR are labeled 98 (or 86), 89 or (68), 16 (or 91) and 30. Where do I solder these?

Hi,
sorry just saw this.I have sent you two separate packets of ldrs.Both the packs were marked as L1/R1 etc.Don't worry if you have mixed them,contact Omishra he might have datasheet for matched Jfets with him.

Regards,
Sachin

 

[mbhangui]

Sachin,

Love the power supply kit. Is it possible to get another kit? Let me know if you have the parts so that I can transfer the amount.

Appreciate the work you and Om are doing

 

[mbhangui]

Re: Power supply

• In continuation from here.
• We reffered Elliot Preamp power supply and LM317/LM337 datasheet, application notes for hints. Also we put some of experiences into this.
• This power supply based on low noise linear voltage regulators LM317 (2 numbers for +24V and +15V) and LM337 (1 number for -15V).
• It take input voltage from transformer, any from (18-0-18) to (32-0-32). (minimum 500mA for PASS B1, LDR Volume Control and CNC phono stage). More current is not an issue as regulators can provide upto 1.5A but heatsink will be required for regulators and output filter coils need to be rechecked.
• Output is designed to provide (+24, 0) and (+15, 0, -15). Output voltage it set using trimmers in each power line which could be adjusted with small screw driver. You can settle at any preferred value but need DMM for this voltage reading.
• If you plan to power up CNC phono stage then please use r-core or EI transformer without overlapped winding. This will couple less noise from ac mains power line. (as it is understood that toroidal transformer have more capacitance between primary and secondary, hence more noise coupled through it)

Please feel free to ask more questions.

Om. Can you refer me to the circuit diagram for this.

 

[omishra]

Re: Power supply

Om. Can you refer me to the circuit diagram for this.

Here you go - rectifiers diodes and coils are changed to suitable current value.

 

[Audiodoc]

@Sachin. I am interested in purchasing a pass b1 PCB as well as two pairs of matched SK170s if they are still available. Don't want to mail spencer again. Please inform me any are available.

 

[bibin3210]

@Sachin. I am interested in purchasing a pass b1 PCB as well as two pairs of matched SK170s if they are still available. Don't want to mail spencer again. Please inform me any are available.

@Audiodoc, Except PCB I have all the components including matched SK170s with me. Please let me know if your are interested.

You can see the details of components here http://www.hifivision.com/diy/21036-pass-b1-88.html#post415499

Thanks,
Bibin

 

[Audiodoc]

@ bibin. I have a working pass B1 and am presently testing my pass BOZ JFET version which also uses the SK170 matched transistors which I had procured from spencer and have probably gone kaput. Although I will be replacing the IRF610 transistor from the power supply section as the supply voltage is 13v instead of the 16v. If it is possible to purchase a matched pair I can rush through to complete a long standing project.

 

[anilva]

@ bibin. I have a working pass B1 and am presently testing my pass BOZ JFET version which also uses the SK170 matched transistors which I had procured from spencer and have probably gone kaput. Although I will be replacing the IRF610 transistor from the power supply section as the supply voltage is 13v instead of the 16v. If it is possible to purchase a matched pair I can rush through to complete a long standing project.

I have had the same problem with j-BOZ power supply. I have used Jim's boards and have used a IRF610. The power supply voltage output is lower than what the design says, though it works properly. I tihink it is set by a zeners in a chain. Change the values and see.

Please let me know what IDSS match are you looking for the 2SK170s. I might have few.

Cheers.

 

[Audiodoc]

Thanks anilva for putting in the word. What I know from reading from the JFET BOZ design is that the supply design used to give 16v when the transistors were not soldered in. After soldering the jets it dropped to around 13v. It worked normally yesterday with 13v but unfortunately I reopened it today for channel balancing of trimpots and LDR volume control. On completing the same I unknowing swapped the input and output sources possibly damaging the transistors!

It is known that the JFET BOZ works best at 16v and at present I could do with any IDDS matched sk170 to bring it back to life.

 

[Audiodoc]

One more thing the Zener diodes do convert the voltage to 16v. I am also using the jims audio board.

The power supply is a 18v r core which gets converted to 24 v DC and dropped to 16.4v across the Zener however falls to 13.2 beyond the irf610. Have ordered a pair of irf610 too.

 

[omishra]

One more thing the Zener diodes do convert the voltage to 16v. I am also using the jims audio board.

The power supply is a 18v r core which gets converted to 24 v DC and dropped to 16.4v across the Zener however falls to 13.2 beyond the irf610. Have ordered a pair of irf610 too.

That may be due to inline resistance before zener which could drop voltage due to excessive current draw than designed. You have to reduce its value.

 

[Audiodoc]

Hope fm bibin or anilva sell a matched pair of sk170s (any IDDS) to complete this project.

 

[Audiodoc]

Matched JFET 2SK170 pair with the IDSS of the FET will be around 5 - 10 mA.

2SK170, Drain current IDSS
VDS 10 V, VGS 0 2.6 20 mA

 

[bibin3210]

Hope fm bibin or anilva sell a matched pair of sk170s (any IDDS) to complete this project.

@ Audiodoc,

I am planning to sell it as kit for B1, other wise again i need to source it from Spencer.

Thanks,
Bibin