B1 Preamp - Help Me!

[Professor smith]

I am having alot of trouble getting the transistors and capacitors at the moment. I will have to get them online. Can someone please tell me where I can buy these matched Jfets?

Also where do I get the 18V power supplY?
Thanks

 

[Salas]

Ebay is your mate.

As for the pot before or after the unity gain circuit, that depends on where you have the weakest situation. 90% of cases is the driving of the interconnects and main amp's input impedance without loss of signal or response deviations.

 

[Nelson Pass]

http://www.linearsystems.com/distributors_international.html


They do not have to be matched, but it is preferred that they are.

 

[jacco vermeulen]

a lot of trouble getting the transistors

Eeer, Gov.
As you've got your knickers in London, why not just pop over to Grandata in Wembley for the K170 ?

 

[Professor smith]

Eeer, Gov.
As you've got your knickers in London, why not just pop over to Grandata in Wembley for the K170 ?

I sure will. That is within walking distance.


But the trouble is, will they match them for me?

 

[jacco vermeulen]

At 50P each you could ask them for a couple of the same batch run and match them in situ.
Which is what Big Daddy P sometimes does, so he says.

Goodlooking motor and nice birds on your homepage, Prof.

 

[Professor smith]

regarding the capacitors,( not the electrolytics), but the metalised polypropylene, what other types can I use and wat values can they be between for the 1Uf and the 10Uf?

 

[Professor smith]

This is turning out to not be as asimple as I thought. I dont know how to match them, I j ust wanted to buy them and solder them. What can I do?

 

[Salas]

You introduce me to Daphne, I give you 4 matched 2SK170s for free.

 

[jacco vermeulen]

Buy a DMM.

You can pretty much use any cap you fancy, just not the same as a polyprop.
If you're not in a hurry and /or can shortly get by with a crappy, i'm about to order some NOS Wima MKP for 24p per uF, could send you some.

 

[AndrewT]

This is turning out to not be as asimple as I thought. I dont know how to match them, I j ust wanted to buy them and solder them. What can I do?

read your email.

 

[Professor smith]

You introduce me to Daphne, I give you 4 matched 2SK170s for free.

introduce you to her for what purpose?

The other problem is, how will I actually know they are matched?

If I can't do the matching myself, then how else will I know?

 

[Professor smith]

Buy a DMM.

You can pretty much use any cap you fancy, just not the same as a polyprop.
If you're not in a hurry and /or can shortly get by with a crappy, i'm about to order some NOS Wima MKP for 24p per uF, could send you some.

What do you mean by not the same as polyprop?

By the way I found a pair of big electrolytics from a amp several years old. Do you think its safe to use? They might be damaged in some way no?

 

[Salas]

introduce you to her for what purpose?

The other problem is, how will I actually know they are matched?

If I can't do the matching myself, then how else will I know?

 

[Professor smith]

in the meantime can somebody tell me about the power supply to use. I was thinking of 2 9v batteries in series. Is this not good enough?

 

[Salas]

It is very good, but they will be challenged for endurance. Maybe a rechargeable scheme must be employed. Me I had excellent results with LM regulators and no battery life to worry about.

 

[Professor smith]

so can you show me an example of wher to get a power supply?

 

[Salas]

Found a stylish stabilized one for 15-24V with setting pot, made for laptops, in Maplin. You can use it on your notebook when not listening to B1.
That should be easy to get in London, yes?

Link

 

[Professor smith]

yes I went there today and only got the resistors. No other parts available
But the one youre showing me is abit expensive no?
its 120w

 

[Professor smith]

http://www.cricklewoodelectronics.com/Cricklewood/product.php?productid=16932&cat=11&page=1

How about this? will this be good quality?

Its cheaper and also I can go to buy the box for the preamp too.