• Hello and Welcome to HiFiVision.com - an online community for the home entertainment and tech enthusiasts!

    If you would like to ask a question, participate in a discussion and view attachments please Register yourself.

Circuit diagram of preamp for record players

Wharfedale Evo 4.2

Hiten

Well-Known Member
Joined
Oct 17, 2008
Messages
3,076
Points
113
Location
Kalyan
Hi Rajeev
A Magazine "ELEKTOR" has circuit+article for phono preamp (I think with RIAA equilisation). Give me couple of days I will scan it and send it to you
Regards
Hiten
 

Hiten

Well-Known Member
Joined
Oct 17, 2008
Messages
3,076
Points
113
Location
Kalyan
Good Guess Cranky. It Probably must be having ceramic Cartridge.

a preamp only need provide a high enough input impedance and a very small amount of gain, 6 (x2) or 10 (x3) dB should be good
Cranky what is input impedance ? (searched the net but it is confusing) Ceramic cartridges produces good enough voltage so no need of pre amp right ? Sorry I am new to technical things but it is good to acquire knowledge.

BTW If Turntable is old it may not have RIAA Equilisation circuit, or for that matter may only have line out straight from cartridge. so it is good for 78 rpm discs but 45s and 33s require equilisation so can Rajeev put some resistor and use this preamp+RIAA Eq. circuit ? :confused:
 

Hiten

Well-Known Member
Joined
Oct 17, 2008
Messages
3,076
Points
113
Location
Kalyan
Thanks Cranky
This is what I gather (sorry If I sound stupid but I am taking the risk)
in simple language impedance is resistance of total circuitary (for example pre amp) to incoming signal (current ?)
so if impedance is high we need higher signal to drive circuit which may introduce noise interferance etc.
if yes, than ceramic cartridge's high signal (compared to magnetic cartridge) given to low impedance pre amp with resistor in between them will further lower the low fq. (bass) signal
Am I getting it right ? Hope I have not made fool of myself.
 

analogadikt

Well-Known Member
Joined
Feb 19, 2009
Messages
250
Points
63
Location
Navi Mumbai
so it is good for 78 rpm discs but 45s and 33s require equilisation so can Rajeev put some resistor and use this preamp+RIAA Eq. circuit ? :confused:

Dear Mr. Hiten,

I think you still have a confusion about this. Please note that RIAA equalisation is requirement of moving magnet, moving coil or moving iron cartridge. It is not specific to speed. One can play 45 or 33 RPM records with ceramic cartridge, w/o RIAA equalisation pre amp.

Regards,

analogadikt
 

murali_n

Well-Known Member
Joined
Dec 30, 2008
Messages
1,317
Points
113
Location
Chennai
Hai All,

RIAA equalisation was introduced in LPs made after 1960s and is applied prior to etching the grooves The RIAA circuit slightly reduces the bass of the signal. This is done to restrict the movement of the writer stylus deep into the grooves of the Vinyl. During playback the output from the cartridge is again passed thro this RIAA eq ckt which restores the original bass frequencies of the recording.

Hope this helps.

N. Murali.
 

Hiten

Well-Known Member
Joined
Oct 17, 2008
Messages
3,076
Points
113
Location
Kalyan
@ analogadikt : Thanks ! sorry I did not use proper words, should have said records manufactured or cut with RIAA std. (indeed RIAA eq. is not speed specific )
@ Murali : Thanks ! I think same with treble (but equally opposite)
@ cranky : Special Thanks. Sorry to mixup words "signal" and 'output'. Noise analogy was good to understand. :)
With High Impedance preamp we are putting load on source (Ceramic Cartridge) and we get maximum voltage transfer so with less current we can amplify it, right ?
@ Rajeev : Here is schematic for phono preamp with description. If figures are not clear PM me your email I can mail you High Res. image. (Do mention if you have ceramic or magnetic cartridge)
Thanks again everyone
 
Last edited:

murali_n

Well-Known Member
Joined
Dec 30, 2008
Messages
1,317
Points
113
Location
Chennai
Hai Rajeev,

Pl contact Mr.Bajaj of NORGE he made a PHONO input with preamp as added feature for my NORGE 2060 . He will be of help to you.

N Murali
 

aks07

Well-Known Member
Joined
Nov 4, 2008
Messages
348
Points
63
Location
????? ????? ????
Which amp you are planning to feed this HMV record player? Just plug into the AUX socket and hopefully you should be fine. I dont think you are looking for a much nuanced performance from an HMV player with a Crystal pickup but still its a very pleasant sounding thing
 
Top