DIY Super Simple Preamp

[sachu888]

Please count me for the full kit if not you have not counted me already. I am keen to use this for the MC phono preamp.

Thanks.

Sure Anil.I will close this GB in 2 days and order PCBs and components.

Regards,
Sachin

 

[captrajesh]

I had ordered a SSP kit to use it in my preamp but now intend to go in for a second B1 instead. I'm willing to ship it to someone who is interested.

 

[doors666]

that psu looks like an overkill for an ssp. a lot simpler and cheaper psu can be done for ssp.

 

[omishra]

that psu looks like an overkill for an ssp. a lot simpler and cheaper psu can be done for ssp.

That PSU was designed for very low noise operation and usage like phono preamp where input is <4mV and noise of uV makes large difference. This PS is very very silent if combined with nice r-core. That adds dark background to any preamp.

 

[doors666]

That PSU was designed for very low noise operation and usage like phono preamp where input is <4mV and noise of uV makes large difference. This PS is very very silent if combined with nice r-core. That adds dark background to any preamp.

No denying that, but the psu was designed for pass b1 and the phono stage in mind. An ssp needs just a single voltage. since its opamp based, it might have a pretty good psrr also (havent checked it though). I remember seeing ne5532 specs, it works upto 44v, hence even a regulated one might not be needed for ssp. At the very minimum, the parts for the 24v portion can be omitted from the same board. R-core requirements also will be lesser as there is no gain or power hungry components, but then again, there will be hardly any savings in r-core for dropping a few watts.

Has anyone tried the ssp with a gain and used it as a headphone amp, a la cmoy.

 

[mbhangui]

If I want to use volume control for SSP, what pot should I use? Should I connect the pot to the output?

 

[murali_n]

Hi bhangui,

You can use a 50k stereo pot at the input, refer the PCB diagram.

N.Murali

 

[vin_eme]

There is already a provision in the PCB for the volume pot. It can be around 47k or 50k dual gang volume pot.

 

[sachu888]

If I want to use volume control for SSP, what pot should I use? Should I connect the pot to the output?

Hi,
Youcan use one 47k/50k Dual gang or two 25k mono Volume pots.There are CW,W and CCW prints on PCB for each channel(Left/Right)
CW: Clock wise
W: Wiper
CCW: Counter Clock wise
If you look at the pot from the front, where the knob goes with the connections at the bottom the left hand side connector is CCW, the middle one is W and the right hand side one is CW. The wiper is the contact that is connected to the shaft. Pic for reference

By sachu888 at 2012-08-11

Edit: If you don't want to use volume control pot then add 1M ohm shunt from input (wire pad 'W') to ground (wire pad 'CCW') of each channel. This makes PS ground reference at the input of OP AMP,else you will have DC output voltage in SSP,and this could be harmful to your Amp.

Regards,
Sachin

 

[omishra]

One more example -

Each line stands for 1 channel, consider below,
1 is CCW (ground on PCB)
2 is W ( wiper, the changing volume level)
3 is CW ( input signal)

 

[mbhangui]

Thank you for all the replies. I managed to get the volume control at Ritchie St. Chennai (looks exactly like the picture that omishra has posted). I was actually looking for a high quality something like this (Alps or Bourns Pots)

Some 6 years back I had managed to get the above kind at Ritchie St but I am unable to locate the shop. Anyone from Chennai who knows which shop deals with this imported pots (made in Mexico/Italy as far as I can recall).

 

[vin_eme]

Here is my preamp build. I would appreaciate if you can correct me if anything went wrong?

Let me know if you need further help on this...i will be able to guide you..

 

[santnai]

Yes Sir your help is very much required. Appreciate it !!!.

Regards,

Santosh

 

[spirovious]

I had used 100k for volume control when gain is more(not this,but for double decker perhaps).

 

[santnai]

Hi Vincent,

Please find attach some more snaps with closer view.

Regards,

Santosh

 

[kroyin]

If you guys liked OPA2134, give OPA2111 a shot.
With 2134 in my setup I found bass to be overpowering & bit floppy,2111 makes it a lot tighter

 

[2chFreak]

If you guys liked OPA2134, give OPA2111 a shot.
With 2134 in my setup I found bass to be overpowering & bit floppy,2111 makes it a lot tighter

Try BB OPA 2107 (its a poor man's 627)

Make sure you bias it in Class-A for approx. 7.5 ~ 8.0 mA

 

[omishra]

Hi Vincent,

Please find attach some more snaps with closer view.

Regards,

Santosh

Santosh, try one thing. Remove OPAmp carefully and measure voltage between (ground, +) and (ground, -) pairs also same at pin 8 and pin 4 wrt ground. They should same with same polarity. Pin 8 is positive & pin 4 is negative.
If above are okay then try any cheap OPAMP like TL072 for testing. If everything is working then try costly OPAMP I suspect your current OPAmp. Did you solder socket first then insert IC into socket?

 

[vin_eme]

Om,

Sachin infact shipped a replacement opamp as well. But same symptoms. Santosh is planning to visit my place this weekend. We will try to sort it out and update.

Santosh, try one thing. Remove OPAmp carefully and measure voltage between (ground, +) and (ground, -) pairs also same at pin 8 and pin 4 wrt ground. They should same with same polarity. Pin 8 is positive & pin 4 is negative.
If above are okay then try any cheap OPAMP like TL072 for testing. If everything is working then try costly OPAMP I suspect your current OPAmp. Did you solder socket first then insert IC into socket?

 

[quad]

It may be a good idea to include cheap (Rs 10 or so) NE5532 or TL072 opamps
also in the kits, which may be used for testing. Extra cost incurred is negligible.
If it works well, then replace with the expensive, audiophile opamp.