John Curl's Blowtorch preamplifier part III

[Waly]

Waly, Tom's amps are composite amplifiers. The newest iteration uses OPA1611 with the LM3886 in the feedback loop.

Not the one shown in #1888, it is not composite but a simple LM3886 “done right”.

 

[Waly]

Design an amp and show it. You've let off enough hot steam to power a river boat.

I would, but I can’t find any supplier of monocrystalline silver wire blessed by Tibetan monks. Without, it would only be mid-fi, and I’m not doing mid-fi.

So for the time being, I’ll keep shoveling microwave ****, it pays the rent, and have some fun with DIYAudio. Thank you for your attention, I’m grateful to the moderation team for promptly approving my messages, for now I’ll get off my soapbox.

 

[DPH]

When you remember, got me curious which one?

There are a few TI, but the OPA164x and I'm 95% sure the OPA827 are silicon on insulator (dielectric isolation): http://www.ti.com/lit/an/slyt595/slyt595.pdf

I'd have to look closely at whether AD's offerings are as well, but wouldn't surprise me.

Waly, Tom's amps are composite amplifiers. The newest iteration uses OPA1611 with the LM3886 in the feedback loop.

Depends on the model, think he's got a more basic model as well.

 

[Waly]

There are a few TI, but the OPA164x and I'm 95% sure the OPA827 are silicon on insulator (dielectric isolation): http://www.ti.com/lit/an/slyt595/slyt595.pdf

Nope, straight from the horses’ mouth, it’s high voltage SiGe, same process as the OPA211. Both great opamps.

 

[DPH]

^ Operational Amplifier (Op Amp) OPA211 OPA827 | Texas Instruments

These devices were developed using the industry's first complementary bipolar 36V silicon germanium (SiGe) process, BiCom3HV.

Wouldja look at that. There we go.

 

[chris719]

Not the one shown in #1888, it is not composite but a simple LM3886 “done right”.

Ah, I should have checked the page. 😱

 

[chris719]

^ Operational Amplifier (Op Amp) OPA211 OPA827 | Texas Instruments



Wouldja look at that. There we go.

Yeah, regardless of the exact process you're right that John C mentioned and I think measured low input CM distortion for OPA164x and 827.

 

[EUVL]

Have a look on OPAx172

CMOS Input ?


Patrick

 

[Terry Demol]

When you remember, got me curious which one?

Joe,

It's the OPA164x family.

This is a useful feature when dealing with moderate to high (especially unbalanced) impedances.

cheers

Terry

 

[billshurv]

OPA1642 make a rather fine MM phono stage with several fringe benefits 🙂

 

[ticknpop]

I’ve used Richard’s caps for 20 years in dacs, preamps, power amps, and the speakers use exclusively the film and foil crossover caps, (only polystyrene in the tweeter circuits). The phono stage uses 1% Rel teflons for the RIAA network.

Next weekend we’ll be running a DIY meet in Toronto, The dac, power amp, and speakers I am demonstrating for my part of the meet all use these caps exclusively , we’ll see if anyone notices................

 

[scott wurcer]

scott wurcer:
47Labs' secret for getting the best out of chips.

egads, not the well-known short Rf path combined with: 1000uf only ps caps

No it was to minimize the "delay" in the feedback.😉

 

[scott wurcer]

Mouser has them at this price for just one and in stock. They are under a buck at ten quantity for some. Much better form factor than the Rels also.

Sorry, I didn't check every distributor they were non-stock at some places.

 

[billshurv]

What I love about 47 labs is how much they got wrong and yet still had people praising it. It sort of encapsulates one section of boutique audio in one expensive flawed product 🙂

 

[gpapag]

I thought aerospace grade aluminum is the 7000 series. It sounds more shiny compared to the rather dull 6061.

Obviously I was being tongue in cheek. There are 2000, 6000, 7000 series aluminums that are "aircraft grade." For whatever it's worth, but yes primarily 7070/7075. The higher corrosion resistance of 2024 gives music a lovely liquidity.

I understand the nature of the talk 😀 😉 but please allow a few words.
"Aerospace grade aluminum" refers to many different alloys of specific heat treatments. The way used here is very loose, marketing talk.
It is the conformance (through traceable paperwork) to some specification standards (SAE, ASTM ) for manufacture, test, handling, storage ect that makes a certain wrought aluminium alloy “aerospace grade”. Conformance to such standards costs a $$$. (99.999% totally useless for commercial audio enclosure use)

http://www.aluminum.org/sites/default/files/TEAL_1_OL_2015.pdf
http://www.lu.fme.vutbr.cz/pistek/literatura/PLKI ANGLICKY/PLKI ANGLICKY/AIRCRAFT MATERIALS.ppt
Search - SAE International
ASTM International - Standards and Publications

George

 

[Joe Rasmussen]

OPA1642 make a rather fine MM phono stage with several fringe benefits 🙂

Thanks guys.

 

[scottjoplin]

I've a Cannondale mountain bike made out of 6000 series aluminium, I striped the metallic green paint off it and now is sounds excellent, almost other-worldly YouTube YouTube YouTube YouTube

 

[Max Headroom]

Anybody have recommendation please for 1uF or so SMD series coupling caps available from RS Components ?.

Dan.

 

[Tournesol]

I would, but I can’t find any supplier of monocrystalline silver wire blessed by Tibetan monks.

zzzzz...
Don Quixote, having lost his war against wind turbines (cfb amps), comes back to us after a long and painful absence with a new crusade against pesticides and other audiophile nuisances.
Using the same weapons (the repetitive comic) we do not see a favorable outcome to his new fight.

 

[billshurv]

Well I found his comments funny.