Hello!
I want to make a preamp for 78 speed records. I know they use many different equalization curves. It seems that there are no kits for making such a preamp. I have seen nice looking comercial products but very expensive, such as:
http://www.vadlyd.dk/English/RIAA_and_78_RPM_preamp.html
Someone in another thread posted a link to a circuit diagram of a preamp that might work. But, I cannot understand just circuit diagrams. If people think it looks good, how can I build or learn to build it just from this diagram?
http://www.rfwilmut.clara.net/repro78/circuit.html
Or, perhaps there is a simpler way to do this? I am sorry I am so ignorant - I don't know how these different curves are made by the preamps. But, is it possible to have a preamp with a few knobs that you can turn, to vary different factors of whatever is making those curves? So that way be able to manually create the different curves and anything in between? (As I heard many people didn't even stick to the various official curves anyway).
For example, would any of you out there like to design a nice simple preamp like that, with some knobs to vary the curves?
That could be very nice right!
Best wishes
Justin
I want to make a preamp for 78 speed records. I know they use many different equalization curves. It seems that there are no kits for making such a preamp. I have seen nice looking comercial products but very expensive, such as:
http://www.vadlyd.dk/English/RIAA_and_78_RPM_preamp.html
Someone in another thread posted a link to a circuit diagram of a preamp that might work. But, I cannot understand just circuit diagrams. If people think it looks good, how can I build or learn to build it just from this diagram?
http://www.rfwilmut.clara.net/repro78/circuit.html
Or, perhaps there is a simpler way to do this? I am sorry I am so ignorant - I don't know how these different curves are made by the preamps. But, is it possible to have a preamp with a few knobs that you can turn, to vary different factors of whatever is making those curves? So that way be able to manually create the different curves and anything in between? (As I heard many people didn't even stick to the various official curves anyway).
For example, would any of you out there like to design a nice simple preamp like that, with some knobs to vary the curves?
That could be very nice right!Best wishes
Justin
Just a thought on early equalization
.
I got a bunch of real old 78s from my parent’s estate. I digitized about 60 and afterwards did some approximate equalization. I then compared a few “Two Black Crows” numbers with some remastered stuff I have on vinyl. With records made in the 1920s I don’t know if there is any equalization that works. What I usually did was bump up the 4 to 6 kHz range and cut off anything above 8 kHz. Seems there is nothing up there except noise.
Anyway here is a link to some of my feeble efforts.
http://dvautier.home.comcast.net/records/records.htm
.
I got a bunch of real old 78s from my parent’s estate. I digitized about 60 and afterwards did some approximate equalization. I then compared a few “Two Black Crows” numbers with some remastered stuff I have on vinyl. With records made in the 1920s I don’t know if there is any equalization that works. What I usually did was bump up the 4 to 6 kHz range and cut off anything above 8 kHz. Seems there is nothing up there except noise.
Anyway here is a link to some of my feeble efforts.
http://dvautier.home.comcast.net/records/records.htm
The Bugle Pro uses the same circuit board as the Bugle, but with the switchable resistors and capacitors for variable EQ added. So they should sound pretty much the same. A BP also fared well at the phono shootout at ETF05. Yes, it will run at 100Vac.
Oh, I forgot, this one is even better:
www.hagtech.com/pdf/monogram.pdf
Then someone pointed out this new machine to me (but it is not DIY):
http://www.toneimports.com/sentec/sentec_eq10.html
jh
Oh, I forgot, this one is even better:
www.hagtech.com/pdf/monogram.pdf
Then someone pointed out this new machine to me (but it is not DIY):
http://www.toneimports.com/sentec/sentec_eq10.html
jh
hello just in case their is somebody out there. i have a question about the monogram schematic.where their is a 'constant current sink which replaces R18'. what is this and where would it go in the circuit. i am fairly new to this and havent come across this before so any help would be greatly appreciated thank you very much. Sean
78RPM records did not have standard equalization curves. The RIAA curve came out later. Every manufacturer used its own equalization. Your circuit will need a rotary switch to select options. Try to find a copy of "The Audiophile's Technical Guide to 78RPM, Transcription, and Microgroove Recordings" by James R. Powell, Jr. This book will give you more info than you dreamed possible.
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