B1 Buffer Preamp

[AndrewT]

Have I ordered enough to get the two pairs that I need for the DCB1?

I've ordered 20

Plenty.
Remember I said you only need selected Idss.
You will get enough that are close enough.

Have you measured the Vgs of the devices in your B1 yet?

 

[dirkwright]

There are certainly plenty available at the moment.

If we all order 20 to meet our requirements we can have a DIY bucket with all the mis-matches. A mismatch handful of 30 will also provide suitable matches. I'm certainly not going to hoard the ones that I cant use.

OK, when I get my 20 from Mouser in a few weeks, I'll post what I don't need. I have to build a tester for measuring Idss. A 9volt battery and a DMM is good enough for that, isn't it?

 

[KatieandDad]

Not yet, I'm enjoying listening to it while I collect the bits together for the DCB1

I've had to order three relays for the DCB1 as a minimum buy quantity. If anyone needs one they were £1.00 each. P&P will be at cost but they weigh nothing.

 

[KatieandDad]

Any other volunteers to hold the bucket of 2SK170s. I'm happy to store them and re-distribute them - Im not in the game for money - I've got a daytime job that pays the bills.

I may not have the time to match them. I'll just post out as many as you want to borrow for matching.

 

[dirkwright]

It's too bad we don't have PCB's for this that take the LSK389:
http://www.linearsystems.com/datasheets/LSK389.pdf

wouldn't have to worry about selecting for Idss I think.

http://www.trendsetter.com/SearchResults.asp?Search=lsk389&orderby=position&orderway=desc

 

[KatieandDad]

It's too bad we don't have PCB's for this that take the LSK389:
http://www.linearsystems.com/datasheets/LSK389.pdf

wouldn't have to worry about selecting for Idss I think.

I'm making my own. It's not difficult as the Salas DCB1 was single sided.

I can't offer to make you one because of both my respect to Salas and his copyright but you can easily make your own.

Nothing more special than Microsoft Paint is required.

 

[ramallo]

I'm making my own. It's not difficult as the Salas DCB1 was single sided.

I can't offer to make you one because of both my respect to Salas and his copyright but you can easily make your own.

Nothing more special than Microsoft Paint is required.

You can get here a pcb

P-MEZB1-1V10e - Mezmerize B1 Buffer Preamp (Makes 2 channels; Rev 1.0) - Boards

 

[AndrewT]

that needs 7 relays.

 

[KatieandDad]

that needs 7 relays.

I'm not building the version with the relay input selector.

 

[ramallo]

I'm not building the version with the relay input selector.

You can put a jump on the input relay (In any of the seven)

 

[KatieandDad]

Mine will be a hybrid of the B1 and the DCB1.

As I'm driving a DC coupled Aleph 4 I need the output caps and I only need two inputs as per the B1.

Fundamentally it will be a modified B1 with the Salas shunt reg and DC coupled inputs.

 

[AndrewT]

A couple of DCB1s as buffers on Sources that need help and a Mez as an input selector and attenuator and you need 9 relays. With cost of finding and posting relays, I would have ordered more than 3.

 

[AndrewT]

You can convert the B1 to use a shunt regulated supply.
All you need is a single salas shunt regulator.

 

[ramallo]

Mine will be a hybrid of the B1 and the DCB1.

As I'm driving a DC coupled Aleph 4 I need the output caps and I only need two inputs as per the B1.

Fundamentally it will be a modified B1 with the Salas shunt reg and DC coupled inputs.

You need a pair of capacitors (As good as you can) at the output of a regular DCB1 board

 

[KatieandDad]

You can convert the B1 to use a shunt regulated supply.
All you need is a single salas shunt regulator.

That's the way I am going - if you look back through the thread.

 

[KatieandDad]

You need a pair of capacitors (As good as you can) at the output of a regular DCB1 board

I've got the Obligatto 10uF PIOs which are about as much as I can afford but are PRETTY GOOD.

 

[AndrewT]

The Salas Shunt Regulator is just a FET style CCS and a FET style Shunt regulator.
They are both relatively simple.
You could do a p2p single polarity PSU and place that inside the B1 chassis directly above the B1 so that you minimise cable connection lengths after the regulator.

 

[KatieandDad]

A couple of DCB1s as buffers on Sources that need help and a Mez as an input selector and attenuator and you need 9 relays. With cost of finding and posting relays, I would have ordered more than 3.

I know that people hate FleaBay but the Omcrons are cheap and genuine

G6AK-234P DPDT 3A RELAY BY OMRON (2 RELAYS PER LOT) | eBay

 

[AndrewT]

Yes, I bought 20 of them, 4 were broken for which I was refunded without returning the worthless items.
The 16 left were exactly what I needed for 2 Mez and 2 Hyp.

 

[KatieandDad]

As this thread progresses I probably wont use them anyway.

I'll keep my B1 and try it with the Salas shunt regulator.