Pearl 3 Burning Amp 2023

[6L6]

@SomekPoland

This is wonderful!!! Thank you so much, your video will absolutely help people new to SMD see that it’s not that difficult, and assist them in building their Pearl!

I’ll add it to the top post in this thread.

👏 👏 👏

 

[PierreQuiRoule]

Ditto! Great video, and I like the jazz music in the background 🙂.

 

[jackinnj]

With 60R AND the compensation capacitors disabled, you should get a flat line from the 1/f knee to 20kHz

Here are some simulation results for integrated noise -- reminding all that these are just a simulation with the compensation network caps disabled:

Opamp	Integrated Noise (uV) 20Hz - 20kHz
OPA891	223​
AD825	535​
ADA4625	519​
LME49720	824​
LT1113	525​
NE5534	563​
OPA161x	855​
OPA165x	523​
OPA604	546​
TL071	564​
LT1028A	1182​
Notes
LT1028, OPA891,AD825	Single
LME49720	Model is LME49860/NS

 

[Mark Johnson]

That's fun, thanks!

 

[chip_mk]

Blimey, TL071 and NE5534 got identical score.

 

[Toys4Boys]

I see some P3s are using slip on connectors for some terminals, can someone provide details, ie, gauge wire etc?

 

[6L6]

This will have everything, and enough for a LOT more projects.

https://a.co/d/iecpYsb

 

[Toys4Boys]

This will have everything, and enough for a LOT more projects.

Thx Jim, was referring to insulated, female spades.

 

[6L6]

Standard 1/4” you can get by the bag at Amazon or auto parts store. Never have bought from the mouser or DK, they are super expensive there.

 

[Toys4Boys]

Assuming 22-10 awg?

 

[runclesid]

Nice method and thank you for the video. Nevertheless I p

refer Jim's (6L6), beautifully explained on online guide. 🍻

I also used the tape method. I am too shaky to use a tweezers at the final step. Pick up with the tweezers and stick it to the tape. Hold the tape and carefully line it up to match the pads, then press carefully. My practice is on these before doing any on the Pearl boards.

 

[LJT]

Here are some simulation results for integrated noise -- reminding all that these are just a simulation with the compensation network caps disabled:

Interesting, I have taken the liberty of expanding your table with voltage and current noise @1000Hz and sorting by the integrated-noise value.
I do suspect that the model for OPA891 is not weighting current noise properly.
Further, your simulation seem to favor low current noise, maybe not a huge surprise considering the output impedance from the cascoding transistor in series with R10=22K.
From a noise perspective it seems that most any j-FET input is a good choice and total noise seem to be dominated by voltage noise. Given that your numbers are without the bass-boost of the RIAA correction, a low 1/f frequency could be a discrimination factor for op-amp choice.

OPA1642 and OPA2134 is definitely be on my shortlist

 

[SomekPoland]

Thanks for the kind reception. I'll be posting a whole kit review after I assemble and test the Pearl 3. I'll post it here if you guys allow that.

 

[mhenschel]

I too have only two (unsteady) hands and was going to try "third hand" tweezers using an elastic band to provide local steady "grip". I thought I might use chop sticks for extra reach if necessary.
(Full disclosure; not an original idea. I think someone -- probably 6L6 -- made this suggestion for the Wayne preamp)

 

[Auricle]

More shaky hands - I am going to try wooden clothespins like @sffrhd showed in post # 1950. Amazon has some jumbo (4" long) pegs that I hope will reach the FETs. Are there any reasons to avoid this?

https://www.diyaudio.com/community/threads/pearl-3-burning-amp-2023.404054/page-98

 

[mhenschel]

I liked those too but...
I wonder about the pressure. with the elastic band idea you can pick an elastic "strength" and double up as needed.

 

[Auricle]

Yes, I can see the pressure issue. Perhaps elastic bands around the clothespin handles to offset the pressure.
On a bad day, I could set the wood on fire. ;-)

 

[sffrhd]

I also made these (projects beget projects) for more reach. They reduce pressure. Next iteration will have the extensions glued to the outboard side of the clothespins to square up the attack. I used american cherry, use what you have lying around!

 

[Auricle]

Beautiful ! Neither Norm Abrams not Tom Silva could have done better.
I'm sure both of them would have appreciated your choice of American Cherry for the wood.

 

[audiorasp]

This is the "third hand" type tool I made for smd soldering. The tweezers ( https://www.amazon.com/dp/B095PHSKLV?psc=1&ref=ppx_yo2ov_dt_b_product_details ) are mounted on a steel block so that they pivot. Pick up the part with the tweezers, position over the pcb then solder. I used an AmyAlice filter pcb and a random 1205 resistor for illustration.