Paradise phono stage

[pdul]

With the risk of sounding ignorant. Who is Frans?😱

 

[Joachim Gerhard]

2 cents a pop. so they come good and cheep-

 

[pdul]

Ok.

 

[Joachim Gerhard]

Here is Frans :http://www.diyaudio.com/forums/analogue-source/165603-balanced-input-all-dc-coupled-riaa-preamp.html

 

[pdul]

That is really cheap indeed.

 

[pdul]

FdW ok, i didnt know his real name.

 

[Joachim Gerhard]

I think that price comes when you buy 1000. It is still only 20€.

 

[pdul]

It is ok if you mean 500 of each otherwise it is not diy level anymore😱

 

[Benedetto]

Buy thousands and share/trade.
So ıts stıll dıy 4 all.
😀

 

[Joachim Gerhard]

I use that transistors everywhere. They are really universal good.

 

[pdul]

Well, I hope i am covered with the ones coming from you, plus the new batch i ordered from Conrad🙂

 

[pdul]

The pinout will make Irish dancers on most pcbs that i have right now😀

 

[Joachim Gerhard]

I hope you have a reason to dance when your build is ready ?

 

[studeb]

what is the target hfe?
are we matching total hfe per quad? top against bottom? for both sections?

@ pdul the Fairchild TDS lists the -40 group hfe as 250 ~ 630, so yours are just on the low end of the scale.

 

[pdul]

And many of them below, unfortunatly😡

 

[Joachim Gerhard]

I match the input stage, top and bottom and the mirrors, top and bottom. Absolute hfe is uncritical so even a 300/300 match is fine. 10% match in each functional section is good enough too. I can tell you even something : Low hfe ones often have less noise and higher early voltae so high hfe is not the only parameter.

 

[Joachim Gerhard]

Read this and start to understand :http://www.essex.ac.uk/csee/research/audio_lab/malcolmspubdocs/J7 Fuzzy distortion.pdf

 

[Radiokaputt]

Thanks for making this clear, Joachim. So a close match is better than searching for high hfe - lesson learned 🙂

 

[Joachim Gerhard]

Yes, before you throw away the low hfe send them to me !

 

[Radiokaputt]

Guess I'd rather bring them along personally 🙂 Off for today need some hours of sleep now.