DIY Moving Coil phonostage

[sachu888]

I will be pairing it with Denon 103 cart

Hi Sajith,
I just read this.It will require 2 X40 ohms and 2X 1kohms resisters which I already have.This Phonostage can be used with any MC cart available in the market.You just need to replace 4 resisters,if you decide to change cart in future.We have put PCB terminals,so no soldering required to swapping them.

Regards,
Sachin

 

[anilva]

Sachin,

Is there a suggested power supply circuit for this preamp? I am sure it requires very low noise PS. I am not too happy connecting this preamp to batteries. I worried about leakage.

Cheers.

 

[omishra]

Sachin,

Is there a suggested power supply circuit for this preamp? I am sure it requires very low noise PS. I am not too happy connecting this preamp to batteries. I worried about leakage.

Cheers.

Hi Anilva,

Yes, I have designed one. I build it for few forum members and using it for myself too.










Our worldwide friends also appreciated it on various forums -
Introducing the (mini) Tower of Power - AudioKarma.org Home Audio Stereo Discussion Forums

Another Super High End Phono Stage! No expense spared... - Page 84 - AudioKarma.org Home Audio Stereo Discussion Forums

PS: I read your thread about F5 and posts in DIY-A. I am too designing F5 turbo V2 PCBs, will seek your opinion at appropriate thread.

Regards,

 

[sachu888]

Sachin,

Is there a suggested power supply circuit for this preamp? I am sure it requires very low noise PS. I am not too happy connecting this preamp to batteries. I worried about leakage.

Cheers.

Yes Om has designed a well filtered power supply for preamp applications.It uses R core transformer.I myself running CNC on it.

Regards,
Sachin

 

[anilva]

Thanks for the great work you and Sachin are doing. Please let me know if there is anything on F5s. I have built alteast 4 of them in different variants and know it reasonably well.

Coming back to the power supply, can you build one for me. I have few things on my plate, before I get to do a power supply and that is delaying the MC preamp build. Please let me know.

Also need the schematics please.

Cheers.

Hi Anilva,

Yes, I have designed one. I build it for few forum members and using it for myself too.










Our worldwide friends also appreciated it on various forums -
Introducing the (mini) Tower of Power - AudioKarma.org Home Audio Stereo Discussion Forums

Another Super High End Phono Stage! No expense spared... - Page 84 - AudioKarma.org Home Audio Stereo Discussion Forums

PS: I read your thread about F5 and posts in DIY-A. I am too designing F5 turbo V2 PCBs, will seek your opinion at appropriate thread.

Regards,

 

[dillihifi]

Hi,

I am also interested in building a PS for the preamp

 

[sachu888]

Thanks for the great work you and Sachin are doing. Please let me know if there is anything on F5s. I have built alteast 4 of them in different variants and know it reasonably well.

Coming back to the power supply, can you build one for me. I have few things on my plate, before I get to do a power supply and that is delaying the MC preamp build. Please let me know.

Also need the schematics please.

Cheers.

Hi Anil,
I can solder your board and send it to you.You will need to enclose it with R-core.I have emailed you instruction manual which includes schematics.You can build this preamp using batteries.You can also put 3 Pin connector on preamp box like I did later upgrade with power supply using same female connector.See pic for reference:
By [URL=http://profile.imageshack.us/user/sachu888]sachu888 at 2012-06-19[/URL]
By [URL=http://profile.imageshack.us/user/sachu888]sachu888 at 2012-02-10[/URL]

By sachu888 at 2012-02-10

BTW: Omishra has his version of posted F5 PCBs here http://www.hifivision.com/diy/28245-diy-pass-f5-turbo-v2-initiated.html#post397942 Please let us know your views.

Regards,
Sachin

 

[sachu888]

Hi,

I am also interested in building a PS for the preamp

Hi,
Please see here http://www.hifivision.com/diy/27074-diy-super-simple-preamp-17.html

Regards,
Sachin

 

[anilva]

Sachin,

I have finished making the preamp. What is left is the power supply. Your idea is good. Make do for the moment with batteries and then change to a external power supply. I was looking at Salas shunt power supply or I wire a simple 7809/7909 based PS.

Cheers.

 

[sachu888]

Sachin,

I have finished making the preamp. What is left is the power supply. Your idea is good. Make do for the moment with batteries and then change to a external power supply. I was looking at Salas shunt power supply or I wire a simple 7809/7909 based PS.

Cheers.

Hi Anil,
I can't tell you about Salas shunt power supply,but 7809/7909 based PS will be nosier compared to LM317 and LM337 based regulated supply.OPS is very well filtered and we can set the desired voltage using screwdriver and multimeter.

Regards,
Sachin

 

[dranil]

Dear Sachu and Omishra,
First of all sorry for the delay in posting this comment.
I was in India last week and brought back the PHONO stage and power supply units build by you. Today I played few records by connecting this to my TT ( I was using built in phono in TT), and the difference is amazing.
I know it will take few hours of play for burning in, but even at this initial stage the quality is very much noticeable.
The units looks great and three cheers to both of you.
Thanks
Anil.

 

[sachu888]

Thank you Dr. Anil for nice comments.Please allow it to burn in for min 30 hrs to get the full potentials of this PS.

Regards,
Sachin

 

[nraghunadh]

Thanks Sachin, just finished CNC Phono stage, And it is sounding good

 

[sachu888]

NIce Raghu,
did you forget to attach a ground wire for TT.

Regards,
Sachin

 

[omishra]

Additionally it is not clear from above post if you have selected input loading dip switch.
Nice build, congratulations.

 

[jls001]

I'm glad to report that I managed to complete the wirings of my Hypnotoad tonight. I don't have a cabinet yet, or more accurately I haven't drilled the holes in the el cheapo cabinet I bought.

I went through a brief heart stopping moment when I powered it up - no sound.

Cross checked and found that I haven't bothered to solder the negative lead of the power supply (battery ). But to my credit I duly wired up the earthing

First impressions were all too short as my batteries let me down. Couldn't hear even one complete track. The blister pack of the battery did say 'ready to use'. Hopefully I should be able to hear it in the morning. All I can say for now is that it sounded very good, except for the bass which was bloated, but I'm sure it will tighten up as it puts in more hours.

Quick question: how long will the batteries typically last? Mine are rated at 350mA.

PS : didn't expect this to sound half this good. Otherwise I would have completed it long, long back.

PPS: this is wired for Denon DL103, so R1 is 16 Ohms and R2 is 393 Ohms (actual measured values for 15 and 390 Ohms 10 percent tolerance resistors).

 

[sachu888]

I'm glad to report that I managed to complete the wirings of my Hypnotoad tonight. I don't have a cabinet yet, or more accurately I haven't drilled the holes in the el cheapo cabinet I bought.

I went through a brief heart stopping moment when I powered it up - no sound.

Cross checked and found that I haven't bothered to solder the negative lead of the power supply (battery ). But to my credit I duly wired up the earthing

First impressions were all too short as my batteries let me down. Couldn't hear even one complete track. The blister pack of the battery did say 'ready to use'. Hopefully I should be able to hear it in the morning. All I can say for now is that it sounded very good, except for the bass which was bloated, but I'm sure it will tighten up as it puts in more hours.

Quick question: how long will the batteries typically last? Mine are rated at 350mA.

PS : didn't expect this to sound half this good. Otherwise I would have completed it long, long back.

PPS: this is wired for Denon DL103, so R1 is 16 Ohms and R2 is 393 Ohms (actual measured values for 15 and 390 Ohms 10 percent tolerance resistors).

Hi Joshua,
DL-103 has DC resistance of 40 ohms and output Voltage of .3mv,so you will need 40ohms and 1k ohms resisters.You can lower the values from 1k to 750 ohms if you find too much gain.
Did you use 2.2 UF PP caps which I sent you with SSP kit?This will improve Bass.Batteries should last you 30-35 hrs.

EDIT: just read your mail.Its Dl-103R,so the values are near perfect.

Regards,
Sachin

 

[jls001]

Hi Joshua,
DL-103 has DC resistance of 40 ohms and output Voltage of .3mv,so you will need 40ohms and 1k ohms resisters.You can lower the values from 1k to 750 ohms if you find too much gain.
Did you use 2.2 UF PP caps which I sent you with SSP kit?This will improve Bass.Batteries should last you 30-35 hrs.

EDIT: just read your mail.Its Dl-103R,so the values are near perfect.

Regards,
Sachin

Yes, I initially requested you to design for DL103R which I was intent on buying at that time, but much water has flowed below the bridge since then . I ended buying something else but subsequently the Denon DL103 (not the R version) still managed to wriggle its way into my system .

OK, that means I am playing it with less than optimal R1/R2 and R9/R10 values. My naive assumption was that 103 and 103R would have the same DC impedance. I will have to go and get 39 Ohms and 1K resistors. Gain is actually low right now. I end up setting my pre-amp about 5 to 6 dB higher than when driven by my other phonostage.

Regarding the 2.2 uF PP caps, I thought I will use them as "upgrades" after I have listened to the basic design for some time. If I use them right away it will be impossible to know the improvement it brings to the table . Or something like that, is my twisted logic.

Some listening impression (about 2 record sides worth, unforced and uncritical listening during morning paper-breakfast ritual): the bass bloat I mentioned last night is most likely due to low battery power. There is no bass bloat on fully charged batteries. None. Period. Perhaps bass was lesser than what I am usually used to hearing from the 103, but that could be explained by the wrong R1/R2 values that I am running now, as well as low burn in.

Stereo images very well, mids are good and highs are well extended. Fairly open sound, hoping to get airier as it puts in more hours. Sound stage is laid back and emanates from well behind the speakers, just the way I like it. I don't have a large listening room so a laid back sound stage really helps expand the virtual room length.

Bottomline: worth every paise of its cost. If you plan to go the MC way, don't even think - just get one.

 

[sachu888]

Hi Joshua,
Just use the correct resister values and 2.2uf caps.This should make the difference.Also buy extra 750 ohm resisters in case you feel too much gain with 1k resisters.Laid back sound is due to Burr Brown 2134 Opamps.I have standardised these Opamps,but you can always upgrade with LME49990.They are SMD type SOIC and you will need 4 of them with adapter like this 2* Dual SOIC to DIP-8 Convert PCB Adapter SMD OPA627 | eBay
You can also try LM4562,which will perform nearly same as 49990

Regards,
Sachin

 

[sachu888]

Please use 1/4 watt Metal film resisters with 1% tolerance.

Regards,
Sachin