Need matched dual NPN transistors for I/V stage, quietest JFET for output buffer.

[Brian Guralnick]

I’m looking for matched dual /or/ pair NPN transistors for the I/V stage on my DAC board. Price is not an issue, what’s the best known available transistor/or/ dual transistors available?

I also wish to buffer the output with a JFET source – follower. My guess that the MPF102 might do fine, but, is there a much better choice of JFET? Might I be better off with a class A, or class B emitter-follower circuit?

 

[ppl]

IMHO Linear Intergrated systems makes some of the best Small sing transistors available. http://www.linearsystems.com/ also Analog devices MAT-02 and MAT-03 are nice Bipolars. Hope this helps

 

[Fred Dieckmann]

Matched pairs and fets

2SA1349 and 2SC3381 pairs

2SK170 fet

All Toshiba devices and my fist choices.

All line level circuits (that is, anything but the output stage of a power amplifier) are class A

post-HH

 

[mevangel]

Schematic?

Hi Brian,
can you show us the schematic you use for I/V conversion?

Marco

 

[Brian Guralnick]

IMHO Linear Intergrated systems makes some of the best Small sing transistors available. http://www.linearsystems.com/ also Analog devices MAT-02 and MAT-03 are nice Bipolars. Hope this helps

Wow, dual bipolar & dual J-Fet in SO-8 will make a real nice layout. The only problem here is to match 2 of each device, 1 pair for the Left, & other for the right.

Rough draft of my I/V section comming late tonight, maybe even some scope shots using MPSH10s & MPF102s!

 

[Fred Dieckmann]

The only problem here

that and the fact that the Toshibas will sound better.

Dual Toshiba fets 2SK389 and 2SJ109


But what do I know,
Fred

 

[promitheus]

Do you already have a circuit ready?
I need something for my DAC also.
It would be very nice of you if you could us the schematic.

 

[tschrama]

Hi,

Dont want to be irritating, but I could use a nice I/V schematic too, to complete my DAC... (I did search the forum and found some usefull one .. just being curious..)

gr,
Thijs

(Fred... nice to see you back on the forum.. !)

 

[Brian Guralnick]

My 2 transistor I/V converter has moved to it's own topic, go here:

http://www.diyaudio.com/forums/showthread.php?s=&postid=75401#post75401

 

[ppl]

Fred Dieckmann> I asm interested in why you would Think the 2Sj109 & 2SK389 would sound Better. I have used Both manuffactures Transistors and while The Toshiba's sound good IMHO I Think the Linear systems transistors are loser noise and lower Ciss. However i am open to your reasons

 

[Brian Guralnick]

Re: Matched pairs and fets

2SA1349 and 2SC3381 pairs

2SK170 fet

All Toshiba devices and my fist choices.

All line level circuits (that is, anything but the output stage of a power amplifier) are class A

post-HH

I've been to Toshiba's web site, I cant find these devices.
Can you point me to their data sheets.

 

[Brian Guralnick]

IMHO Linear Intergrated systems makes some of the best Small sing transistors available. http://www.linearsystems.com/ also Analog devices MAT-02 and MAT-03 are nice Bipolars. Hope this helps

I like the matching of the LS312. The only problem here is that I cant find any graphs for the component. When I design my Class A amps, I like to run the components in their sweet spots.

 

[hatasa]

Hi Brian,

I would like to know is it possible to connect with the +/-15 supply.

And I would like to ask is the Vout in balance mode if I connect the GND to VGGND?

 

[stadams]

Toshiba JFET's data sheets.

Here ya go,

http://www.schuro.de/japan-dat.htm.

Later,

 

[Brian Guralnick]

Hi Brian,

I would like to know is it possible to connect with the +/-15 supply.

And I would like to ask is the Vout in balance mode if I connect the GND to VGGND?

Wrong topic, ask the question on the IV page...
>>>>>>>>>> I PLACED YOUR ANSWER THERE <<<<<<<<<<

---------------------------------
Toshiba JFET's data sheets.
Here ya go,

http://www.schuro.de/japan-dat.htm.

Later,
__________________
-Todd
----------------------
As for the 2SC/J/K page, thanks...

 

[ppl]

Brian Guralnick> I know what you mean I used the LS-312 & LS-352 as complimrntry Diff Amps in My Diy power amp. I read the Hfe vs Icq on the spec page and to me it looked like the gain started to drob above 3-4 Ma. I selected 2 Ma and this worked fine. later conversations with LIS's App Eng. confirmed this. I mentioned about the lack of Graphs and got a If you need graphs ya don't Know how to read data sheets. Da I already determond from the data sheet the 2Ma Icq point and so gess i read it right. boy thay sure sound good in that application to me.

 

[mlloyd1]

more on suppliers of good JFETs ...

InterFET in Texas (?) also can supply high quality "Toshiba like" devices. They have great replacements for the 2SK170 and 2SK146

mlloyd1

 

[stadams]

Searching...

I have searched the web for a data sheet for the 2SC3381 and have yet to find one. Does anyone have a link to this datasheet or maybe willing to post the .pdf to the forum?

By the way, MCM Electronics had the 2SC3381 and the 2SA1349 in stock as of this morning--rather cheap too! I bought 20 of each.

Thanks,

 

[Brian Guralnick]

Has anyone had any experiance with Crystalonic's Dual & quad transistors?

http://www.crystalonics.com/Dual and Quad Transistors.htm

 

[ppl]

Brian> I have'ent used this Firms transistors but I have used the Motorolla Quad types thay replace in the Dip Pkg. Thay should work Good for what you want. Oh Thanks for posting the Link. I may need to get me some more Quad Comp Tr's.