OPA1656 Phono Preamp: Split from OPA1656 thread

[mlloyd1]

i got the same lecture when I was starting out, with the additional caveat: "just be able to tell me what you learned from that mess and we'll call it education"
🙂

 

[JRA]

I found this bit on breadboarding:

https://forum.digikey.com/t/definitive-guide-to-breadboarding-circuits/36584

Good basic stuff plus links to further tips and techniques. Good God - start with the DIP8 OPA627s you already have and sleep well at night.

 

[carlmart]

carlmart. Yes. You've be at this for 5-years. Asking for op-amp models, LTspice simulations ad nauseam, searching for and quoting topologies and techniques but you never build anything. Doing a quick search here I see the top three op amps being 1) BB 627; 1a TI 827; and 2) BB 2107 There are your choices. And maybe a BB 1641/42 difet.

C

Thread 'OPA828 for RIAA preamp'

2019-09-25 5:06 pm

Has anyone tried the OPA828 as part of a RIAA preamp?

Having FET input and being reasonably low noise, it looks as a good candidate.

• carlmart
• Replies: 38
• Forum: Analogue Source

Simulations will tell you nothing more. The 627 was introduced by BB in 1989. It was Hi-$$ then as is now. It is still in the general "best of" conversations and forum chatter. (2008+) It is still hi-$$ b/c of curiously continuing demand; TI has to produce it on old fab lines - and they don't like that. Don't quote me.

But you have OPA627s in DIP8! So go for it. But, don't go for an everlasting search for "simulations". Go for the opinions of critical listeners. JMHO.

Not really. Build I built a lot of audio stuff, both for my personal use and for sale.

I have been a professional audio recordist for film & video all my life, so I had a wide experience as a user. Now I'm retired.

In the late '90s I designed and built a portable professional mic preamp for video, using the SSM2017, a short adventure for the US market, and sold them all.

Redesigned a new audio project for video preamp in 2015, using THAT mic balanced chips, and presented it in the Las Vegas annual video show, but it didn't go into production. Just the prototypes.

MM preamps built only discrete ones. Projects by Graham Nalty and Elektor.

Living where I live it became difficult for me to build stuff from the beginning, that is design the pcb and fabricate it all, particularly legit parts. With Brazilian import taxes, importing parts from the USA became very expensive, shipping also did.

So I decided to go a different way. Start from existing Chinese kits and replace the passive parts. That's how I found this thread, and got help from Marcel in modifying the schematic for adding a HP filter.

This week I got the precise Aliexpress pcb that I will use to build the single chip preamp you built.

I will now open a new thread, where I will suggest how to use three different Aliexpress pcbs: a single opamp active preamp, a two opamps with passive filter preamp and a two opamps passive active preamp, as was shown here in this thread.

Gathering all the parts, including regulated supplies choices, has taken a lot of time.

 

[JRA]

Well, I for one was just going on what I saw here - and five years ago, asking the same questions, having things string-out but I am spoiled rotten re my addiction to point-click-and ship, PayPal, 3-day delivery to my door... 0.1% Rs? Sure, how many? That new thread would be interesting.
Comments unasked for re the MOFI approach:

Do you really think all that front-end RC stuff is necessary?
You probably noticed that the 220uF is out-of place.

Maybe I'll shut up.