Ok, you are my man. Make the decision or we talk here for the next 3 years
The (designed) 160mA (about) is good for the 105mA demand. No change needed!
Thanks Michael and Frans. So we only need the final schematic and make the decision if we make the EQ adjustable and how.
By the way i found now a really god replacement for the ultra low Rbb´ unobtainiums.
They are the Sanyo 2SA1208 and 2SC2910. They are in full production. Please do not redesign the circuit though. The multi degenerated input gives us less distortion then a pair of those with 5 ohm degeneration so i simply put this here for completing my list.
By the way i found now a really god replacement for the ultra low Rbb´ unobtainiums.
They are the Sanyo 2SA1208 and 2SC2910. They are in full production. Please do not redesign the circuit though. The multi degenerated input gives us less distortion then a pair of those with 5 ohm degeneration so i simply put this here for completing my list.
I have too little records to need other EQ then RIAA. I plan to make a three way equalizer anyway that goes between the pre and power amp that can copy nearly any curve you like.
Lets stick rigid on RIAA. I do not like any switching to be done or spoiling the layout.
That sounds hard, sure, but my equalizer will solve that problem.
Lets stick rigid on RIAA. I do not like any switching to be done or spoiling the layout.
That sounds hard, sure, but my equalizer will solve that problem.
men are more predictable, but who want that in life. there women are wonderfully complex and at least to me fantastic and mysterious....
I do believe the problem here is the switching, i have experimented at lot with volume controls and input-switching...and it does not come for free, relays and mechanical switches does add a layer of haze that is simply not there with a direct soldering, so the question is weather we want to degrade the 90% for the last 10% or less...
I have in my RIAA thread made comparison of the different De-emphasis curves, With those in mind it should be possible to develop networks to the additional curves, this can be done on a add-on board, with relays or mechanical switches
I do believe the problem here is the switching, i have experimented at lot with volume controls and input-switching...and it does not come for free, relays and mechanical switches does add a layer of haze that is simply not there with a direct soldering, so the question is weather we want to degrade the 90% for the last 10% or less...
I have in my RIAA thread made comparison of the different De-emphasis curves, With those in mind it should be possible to develop networks to the additional curves, this can be done on a add-on board, with relays or mechanical switches
Is this really what we want ? Of cause i had the idea too of modules stacked a top of each other. My idea of a variable EQ is different. I would for example setup the gain of the Paradise Lost for 40dB straight with simply inserting a resistor instead of the RIAA. The rest would then be done in the equalizer that also provides the rest of the gain, say 20dB.
It could then be setup in such a way that we can boost and cut at 20Hz and 20kHz by 20dB plus a filter in the midrange, also plus minus 20dB. When we fully advance the bass EQ and fully cut the treble we have RIAA. The rest lies somewhere in between. The Tanzmusik can do that, although here it is part of the phonostage and it works very well also allowing to tame problems of the recording and help even EQ the speaker-room interface somewhat.
I say no, no other EQ then RIAA, please people, do not stumble over this stepping stone.
For most transparent sound, please no switching. We really need the 10% or all of our work is useless.
For input loading i would suggest the following : first simulate the input impedance of our circuit, how high it is and how linear. Then we chose a fixed resistor of say 10kOhm that is always there. Parallel to this resistor we use a high quality wirewound potmeter of say 1kOhm that can be switched in. Have we found out the best setting for sound we switch off the wirewound and insert the fitting resistor into phono jacks that are parallel to the input jacks. I found really excellent wirewound potmeters made in Germany that are very smooth action and very low noise. I look it up for the model.
It could then be setup in such a way that we can boost and cut at 20Hz and 20kHz by 20dB plus a filter in the midrange, also plus minus 20dB. When we fully advance the bass EQ and fully cut the treble we have RIAA. The rest lies somewhere in between. The Tanzmusik can do that, although here it is part of the phonostage and it works very well also allowing to tame problems of the recording and help even EQ the speaker-room interface somewhat.
I say no, no other EQ then RIAA, please people, do not stumble over this stepping stone.
For most transparent sound, please no switching. We really need the 10% or all of our work is useless.
For input loading i would suggest the following : first simulate the input impedance of our circuit, how high it is and how linear. Then we chose a fixed resistor of say 10kOhm that is always there. Parallel to this resistor we use a high quality wirewound potmeter of say 1kOhm that can be switched in. Have we found out the best setting for sound we switch off the wirewound and insert the fitting resistor into phono jacks that are parallel to the input jacks. I found really excellent wirewound potmeters made in Germany that are very smooth action and very low noise. I look it up for the model.
I really like the wirewound pot idea but some carts work best with 2k5r... are there any similar pots with greater values ?
EDIT: http://www.conrad.de/ce/de/product/442823/DRAHTPOTI-ABW2-2W-25KOHM-10LIN/0241750&ref=list
I also agree that strict Riaa is enough. The less contacts the better.
EDIT: http://www.conrad.de/ce/de/product/442823/DRAHTPOTI-ABW2-2W-25KOHM-10LIN/0241750&ref=list
I also agree that strict Riaa is enough. The less contacts the better.
Last edited:
For this we could connect the amplification stage and the buffer with wire jumpers, we could then have a RIAA section that could be populated or not, or in your case fitted with a fixed resister for even better performance, then you could buffer your EQ with the buffer and your set... A Swiss Army knife with everything, then people can also just build the riaa with fixed deemphasis circuit
And I do agree. I do have a healthy stack of records, but the need to change EQ (other then RIAA) arises seldom. KISS (keep it simple stupid)
Last edited: