OPENAMP1 - MM phono preamp open project

[smallangryboy]

The boards measure 135mm x 100mm and are very good quality.

Thanks Marra, gutted they are unavailable so have to look for an alternative MM phono stage.

 

[Marra]

Thanks Marra, gutted they are unavailable so have to look for an alternative MM phono stage.

PM sent

 

[Marra]

Many thanks Pavel I have just spent a very pleasant afternoon listening to the Openamp1 in tandem with my Sowter SUT and Denon DLS1 cartridge and must say that I am very pleased with the sound.Thanks again.

 

[PMA]

Nice to hear, thanks for your feedback, Keith.

 

[tER299]

It seems that I'm a bit late, but are there any plans for a batch of new PCBs?

 

[Turbon]

I would be interested as well in 2 boards.

Regards

 

[PMA]

Hello guys, I am sorry but I have not been producing or selling anything of audio in the last year. I will give an info if anything is changed.

 

[Turbon]

Right, thanks Pavel for the information. They surely looks good.

No chance that you would share the gerbers?

Regards

 

[mlloyd1]

PMA;

some comments today in the Blowtorch thread reminded me that i meant to ask you a while ago why you chose LT1010 instead of BUF634 for OpenMM?

thanks,
mlloyd1

 

[mlloyd1]

never mind,
i saw the interesting distortion plot and your comments on opa637+buf634 line stage posted today in the blowtorch thread .

thanks,
mlloyd1

 

[nezbleu]

Right, thanks Pavel for the information. They surely looks good.

No chance that you would share the gerbers?

Regards

I thought I read originally that it was called "OPENAMP1" because it was to be an "open" design, released under creative commons license or some such. Was I hallucinating? Am I confusing this with another project?

It is such a nice design, it would be of benefit to many if it was opened up so someone could organize a group buy or something.

 

[PMA]

The complete circuit may be downloaded from my website. I will probably release gerber files as well.

 

[AudioLapDance]

Finallllly got my phono stuff from the x ...



I can finally upgrade my implementation of a pre on PMA's PCB to the full OPENAMP1


Oh ...

BUF634



HIGH OUTPUT CURRENT: 250mA
SLEW RATE: 2000V/ms
PIN-SELECTED BANDWIDTH: 30MHz to 180MHz
LOW QUIESCENT CURRENT: 1.5mA (30MHz BW)
WIDE SUPPLY RANGE: ±2.25 to ±18V
INTERNAL CURRENT LIMIT

ABSOLUTE MAXIMUM RATINGS
Supply Voltage ........................................................... ±18V
SPEC
Current Output, Continuous ±250 mA

LT1010



20MHz Bandwidth
75V/μs Slew Rate (=75,000V/ms)
Drives ±10V Into 75Ω
5mA Quiescent Current
Drives Capacitive Loads > 1μF
Current and Thermal Limit
Operates from Single Supply ≥ 4.5V
Very Low Distortion Operation

ABSOLUTE MAXIMUM RATINGS
Total Supply Voltage ..............................................±22V
Continuous Output Current (Note 2).................. ±150mA

 

[AudioLapDance]

Here's my pre implementation of PMA's pcb ...



...just to get it up and running.

Now that finally have it back, I can go RIAA!
... Er, where's that resistor pack ....

 

[PMA]

To everyone who might be interested, I have added the Gerber files for free download to the Openamp page:

Preamplifier for MM cartridge

You will find it below the assembled PCB photo, together with the pdf documentation. Should be used for personal use, not for business

 

[atupi]

Very kind of you Pavel! A big THANK YOU from my side.
Maybe we can gather some interested people for a mini GB of pcb's.

 

[Turbon]

Very kind of you Pavel! A big THANK YOU from my side.
Maybe we can gather some interested people for a mini GB of pcb's.

Yepp, I'm in for two boards. Thanks alot Pawel!
Even without the gerbers it would still be an open project. Your decision what to share.

Regards

 

[atupi]

There are any other people interested in this pcb? For a minimal Gb we need at least 10 pcb order.


Sent from my iPad using Tapatalk

 

[Turbon]

I believe this is a very good mm phonoamp. I'm very eager to sample it's sound qualities.

Regards

 

[nezbleu]

That is indeed very generous, Pavel! I already have one so will not be interested at this time. I will say that it sounds very very good. Turbon i powered mine with a Salas shunt reg.