[Glassman]

a great czech audio designer Pavel Dudek (known as DPAudio) made several versions of his Actidamp phono preamp. it was publicated many times in czech radioamateur magazines.. I found this schematic of Mk IV version on some russian page:

all you need to do is change those NE5534 for AD797 and LF411 for something better.. in place of 2SK170 you should use 2SK389 instead (known well from Gilmore headamp) it is a great sounding phono preamp..

 

[marios_mar]

did i mention that it needs to fit the RIAA standard?

Also another question on turntables what is MkI MKII etc?

 

[antomas]

Hi Marios,

there are quite a few phono stage projects on the Tnt site:

http://www.tnt-audio.com/clinica/solidstate.html

I want to build the InDiscreet, sooner or later so, for the moment, I cannot comment on its sound.

RIAA: I'm pretty sure that all the phono stages around conform to the RIAA standard.

MKI, MKII, etc. are the versions of a product (i.e. a turntable): MKI (Mark One) is the first, MKII the second, and so on.

Ciao,
Massimo

 

[peranders]

Mario, check the datasheet of LT1115 . There you have two good basic solutions and you can change opamps if you want. Have you checked my QSXM3 which has chopper stabilized DC-servo. The only one in the world!

 

[marios_mar]

peranders your pre amp its gotta be good but i dont want to spend like 100 dollars only for the PCB. That is the max. amount i want to spend as a DIY begginer. Your stuff is probably more high end than what i can build now and i think they are pricey , except if i did the Swedish K to EUROS convertion wrong!
thanks anyway

 

[peranders]

Mario, in that case check the minimalistic design which can be seen in the datasheet LT1028
This amp can also be seen here

..and yes, you didn't convert SEK-> EUR right....

Check also Rod Elliott. A very basic RIAA isn't complicated.

Check also www.rane.com and their vinyl amp. Schematics are availble!

http://www.rane.com/ps1.html
http://www.rane.com/pdf/ps1sch.pdf
http://www.rane.com/pdf/ps1dat.pdf

 

[marios_mar]

just like you said i want something pretty simple for now. Maybe a simple tube pre amp if there is such.
What are the prices for your kits. Or do you only have pcbs?

 

[peranders]

The basic riaa amp is simple. Look at for example NAD's PP-1. You need one good opamp, some passive parts and a power supply. You can start with a NE5534 which I can give to you and stop at one or more AD797, LT1028 OPA637 etc and a huge PS. 10 USD -> 1000 USD

 

[marios_mar]

ok first send me a link with instructions on making DIY NAD PP-1 preamp. And schematics? Do I need a pcb? Let me know the total cost of it approximately and which parts I can buy from you.
bye

 

[peranders]

I have a pdf of the whole thing but I can't find any link, someone else?

Audio Electronics, 3/00

Drop me a note and tell your email address if noone can't find the link.

BTW: It's rather amazing that the magazine did publish the schematic without permission. NAD got a little bit grumpy for that.

 

[marios_mar]

is this Nad diddicult to build?

 

[peranders]

No not really but it looks like everyone else. Have you checked the Rane amp or the LT1028 amp?

Stefan Lidström has made a hardwired LT1028
http://www.tanker.se/lidstrom/eng/slriaa.htm

 

[peranders]

I think you must state your budget because this is most important here.

What is bad? If you use a 741 opamp you will proably be rather sad but from there to heaven is a long trip.

Most quality for your dollars is a NE5534 plus a discrete output stage with BC5xx tansistors. The second best is a single NE5534.

 

[antomas]

Hi Peranders,

Quote:

Mario, check the datasheet of LT1115

May I ask what do you think of this schematics as well as of the LT1115 chip? Does the LT1010 really need the cap on the output? Do you think the PS could be a basic one (rectifier and caps) or a more complex PS would be needed (regulated, capacitance multiplier)?

Sorry for the many questions and thanks in advance for your answers. I know I asked the right person

Massimo

 

[peranders]

What do I think? The design is descent and very basic, nothing to take patent for but it's so good that I've made a pcb for it. The LT1115/LT1028 is also very good, one of the best this category. Competitor is AD797. For only MM pickup those opamps are some overkill in noise specs. If only MM catridge is chosen many more opamps will do the jobb.

The last thing is a filter because the non-inverting amp create a non-wanted zero. From 2122 Hz you want a drop of 6 dB/octave in eternity but this won't happen. The curve will flatten out eventually. This is only important in MM mode, not MC.

Since you use opamps with good PSRR there is no need for extremely quite supply voltage, like The Pearl or my QSXM2.