Versatile and comfortable passive pre-amp

[Rudi_Ratlos]

rbalu72, I will happily perform a new Group-buy round for the RPRE-V2, but only, if somebody assists me!
Just think of all the tasks I have to do to make this Group-buy a success:

- doing the Hardware design and layout
- program the firmware
- burn the firmware into the PIC µProcessors
- program the IR remote control units to transmit subcodes using system-address X'11'
- keep the BoMs and Builder's Manual up to date

- measure the LDRs and select suitable pairs / quads
- take care of the B1-buffer PCBs and find somebody, who will solder the TPS7A4700
- keep track of PAYPAL money transfers
- dispatch the letters and parcels
- ...

If there is somebody who will take the tasks starting with "..measure the LDRs ...", I will think about a new round.

Best regards - Rudi

 

[tuo]

- measure the LDRs and select suitable pairs / quads
- take care of the B1-buffer PCBs and find somebody, who will solder the TPS7A4700
- keep track of PAYPAL money transfers
- dispatch the letters and parcels
- ...

If there is somebody who will take the tasks starting with "..measure the LDRs ...", I will think about a new round.

Hmm, I do have time, interest and most of the needed skills and equipment. And I'm physically not that far away, so maybe we could continue this with private messages.

 

[amsoque]

All the german guys I knew here at diyaudio (mainly from Paradise Phono thread - and I have to mention Alfred Hesener) are community dedicated persons. I'm impressed. And they know working as a team.

Emil

 

[Rudi_Ratlos]

I have assembled my own RPRE and tested it.
Until now everything works as designed.

I am now waiting for Ales (mravlca) to solder the TPS7A4700 on my PSU-PCB to power the on-board B1-buffer.

Best regards - Rudi_Ratlos

 

[anjump123]

Looking good, Rudi.

 

[Rudi_Ratlos]

I received the TPS7A4700-PSU - PCBs back from Ales, could not resist and soldered a PSU immediately.

The PSU-PCB works as designed!
I jumpered the TPS7A4700 to give a +/-11VDC on the output (to be used with the RPRE's B1-buffer).

I will now start and send you your orders/parcels.
Aradan: tomorrow, then Speakert, then Myint, ...

I wish you a sucessful build - Rudi_Ratlos

 

[aradan]

Hi Rudi,

Sounds great and thank you so much. Might be able to finish it this year than, should be a great new year gift)))

Sent from my ONE A2003 using Tapatalk

 

[anjump123]

Looking even better now, Rudi? Is there any difference in sound quality?

 

[Rudi_Ratlos]

I can no more compare the "sound" of my RPRE, being driven by a dual LT1763-PSU, with my RPRE, being driven by the TPS7A4700, simply because I do no more have the LT1763-PSU.

I can compare the "sound" of the "SALAS Simplistic B1 Buffer" with my current setup.
I do not hear any difference.

Comparing the efforts it takes to build the shunt regulator on the "SALAS Simplistic B1 Buffer" and the dual TPS7A4700 -PSU that I have done a layout for:
you do not need matched components (f.e. LEDs), nor do you need heatsinks, ..., the transformer is "on-board", ...

Another very nice gimmick that I found out: "the simplistic B1-buffer sounds better", when driven by +/- 11VDC output voltages (rather than by +/-10 VDC output voltages),
and to change the output voltages of the dual TPS7A4700 - PSU only needs different jumper settings.

Best regards - Rudi_Ratlos

 

[Rudi_Ratlos]

Find attached a picture of my current RPRE-build.

The "simplistic Nelson Pass B1-buffer" now being driven from my dual TPS7A4700-PSU, adjusted to +/-11VDC.

Best regards - Rudi_Ratlos

 

[Rudi_Ratlos]

Gentlemen, I have asked Santa Claus to give me a 3rd hand this year: my right hand to hold the solder iron, my left hand to hold the roll of tin-solder and the 3rd hand to hold tight a SMD-component.

Find attached some images of what Santa Claus and his helper Andreas (a German DIY-friend of mine) have put into my boots!


http://abload.de/img/pre010gvkxi.jpg


http://abload.de/img/pre018jrscr.jpg


http://abload.de/img/pre005n1uom.jpg

The result (f.e. soldering the TPS7A4700-PSU for the RPRE's integrated simplistic Nelson Pass B1-Buffer) nearly looks professional, doesn't it?

I hope that these pictures will inspire your DIY- instinct and will take away any fear from soldering SMD parts!

Best regards - Rudi_Ratlos

P.S.: It is currently impossible (?) to attach pictures!

 

[aradan]

Wow I was going to ask you this question and got this message great and thanks))

Sent from my ONE A2003 using Tapatalk

 

[ronnydepony]

Hi Rudi,

Where did you buy that third hand for holding SMD-Parts.

Regards,
Ronny

 

[redjr]

Hi Rudi,

Where did you buy that third hand for holding SMD-Parts.

Regards,
Ronny

Rudi,

I like it! Simple, but genius. I have used very,very small alligator clips in the past, but sometimes they get in the way a bit. And you can only use them on the edge of a PCB board, so they are limited. This is a much cleaner solution.

BTW - I'm waiting on a Front Panel Express order for a few of my current projects - one of which is the LDR-RPre. I'll be sure to post a few pics of the progress and the finished product. I can't wait to hear it.

Rick

 

[Rudi_Ratlos]

@Ronny, Rick:

This is the "Do-it-Yourself" - forum!

Best regards - Rudi_Ratlos


http://abload.de/img/aw0010js1r.jpg

 

[aradan]

Oki this is a diy. I am trying to understand how it works), do you have any pictures to give us a clue

Sent from my ONE A2003 using Tapatalk

 

[redjr]

Oki this is a diy. I am trying to understand how it works), do you have any pictures to give us a clue

Sent from my ONE A2003 using Tapatalk

It's the weight of it that holds it in place.

 

[Rudi_Ratlos]

Aradan, I hope that the attached image will give you the needed insight!
Just go to your local locksmith, give him a bottle of wine, whisky, some cigars, ..., whatever he likes, and he will make you this tool!

Redjr's answer has been perfect! The "SMD-part" won't move a µM, and you have 2 "free" hands to solder it!

Best regards - Rudi_Ratlos

 

[aradan]

Thank you keeping in mind I am in SG wine and cigars would cost around the whole price of the preamp))) with this picture I can move an earth thank you

Sent from my ONE A2003 using Tapatalk

 

[Speakert]

Merry Christmas!

Merry Christmas all of you!

Completed the PSU PCB - works great and is set up for 11V.
I just used the same soldering technique as is used for the Micrel voltage regulator.

The result looks a bit rougher than with Rudi's "Orthophon" thirth hand (never knew Rudi was that heavy into vinyl ) appliance for keeping the SMD's in place, but hey I'm there...

Almost there with the RPre too, still some minor thingies, after that I will hook it up in my enclosure. It will replace a previous RPRe version (NO, it is not for sale!), which works great and sounds even better! (i.e. awesome!). Only reason to replace it is the volume adjustment speed, which is a bit on the slow side in comparison to that of the current build.

@Rudi: are the SPO PCB's still availlable? I like one, it's handy to switch things on and off along with the RPre!

Merry Christmas!!!!!!!!