Pre Preamp - what type of components

[batty]

An externally hosted image should be here but it was not working when we last tested it.

This is the CCT of the pre preamp I am thinking of building, could anyone inform me what would be reasonable components to use, not values but type.
I know different types of caps etc. in certain paths alter the sound, but don't know which to use where.

The components are:

Q1 2n4401
Q2 2n4403
R1 100k
R2 330k
R3 & R4 1M
C1 0,1 microfarad
C2, C3 & C8 100 picofarad
C4, C5, C6 & C7 100microfarad

 

[pdul]

Can you post a bigger schematic? this one is unreadable

 

[pdul]

Maybe this can serve as inspiration. This has optic psu

 

[pdul]

The 2200uf can be replaced with 1000uf 6,3v + 220uf or more OS-CONS for less resistance at higher frequenzies. The 40r2 resistor should have the value recommended for load of your cartridge.
This setup works great by the way, i have used it for many years

 

[batty]

Moving Coil Cartridge Head Amps

It is the Common Base Marshall Leech Jr. in the link above, I wish to run each channel from a 9volt battery.
Optimum load impedance for my cartridge is 200 ohms if this makes any difference.

 

[batty]

Can I replace the transistors in your schematic with 2n4401 and 2N4403? as I already have these and are supposed to be very quiet.

 

[Joachim Gerhard]

The ROHMs are much more quiet then the 2Ns but they are run on much too low idle in the LC Audio design. I never understood that but it may be a consequence of what the light supply can deliver in current.

 

[batty]

My main Q is what type of caps and resistors to use in what location i.e polyprop caps and metal oxide resistors, I want to build a good 'bang for buck' pre as I am short on funds.


Also a second thought is would point to point be better than veroboard.

 

[pdul]

True bang for the buck, would be to build paradise

 

[lcsaszar]

I built a similar circuit years ago, with BD167/BD168 power transistors. They were recommended for lowest noise. Also the capacitors between each base and GND totally destroyed the sound. On removing them the circuit began to sing... This is a good example for theory and sound quality being on different tracks...

 

[Bonsai]

The ROHMs are much more quiet then the 2Ns but they are run on much too low idle in the LC Audio design. I never understood that but it may be a consequence of what the light supply can deliver in current.

Can you still get them Joachim? I thought they were obsolete.

 

[Ken Newton]

You could also utilize the JFET based circuits from the ZEN-SEN-CEN thread, which are variations of the Leach MC pre-amp adapted to DAC I/V service.

 

[Joachim Gerhard]

I have a stash of NOS Rohms. They are virtually impossible
to get now.
The same for the Hitachis and Toshibas.
I am testing now alternatives on a curve traces and a noise test.
What could work are Zetex. Many of the medium power SMDs are known to have low Rbb.
I am currently awaiting FMMT618, 718.
From the specs they look good.