Solid State Power Amp Reviews

Thank you for a well written and descriptive review. Did not know about In My Pocket. Wonderful, a keeper!

Hi

Southwire is the largest building wires supplier in Northern America & supplies all types of wires/cables for the civil/building constructions & to nearly all hardwares stores, e.g. Home Depot, Lowes for electrical jobbers. It got its own copper recycling plant to smelt copper from scraped cables & wires taken from dmolished buildings to make its new wires/cables.

The reason I mention it here is I would NOT use any industrial/building wires for audios. I think the Southwire solid wires used in PWR-3 should be THHN (PVC insulation + nylon outer jacket). Excellent building wires for outdoor use. For audio? sorry not for me !

Beldon also supplies tons #14 loudspeaker wires, better than Southwire building wire, IMO.

Listening is believing

Jack L

PS: Amazon also supplies Belden wires for small runs.

Hi

Yes, such "leaking' of RFI/EMI can be conductively from the SMPS hard wiring to the amp stages & AIRborne from the SMPS all over inside the amp housing.

It is practically not easy to stop the airborne RFI emiited from a SMPS unless the entire amp section were housed in conductive Faraday cage effectively grounded. I don't see such electromagnetic shielding box inside the amp to protect the amp section !!!

Yes, SMPS can be very compact in size, efficient for constant voltage/current supply & CHEAP to install, but it is a wild RF beast hard to tame.

I would never want any SMPS to be part of my audio amps to save the RF noise problem. That said, the NMH batteries for biasing all the triodes in my design/built power amp are recharged by an OUTboard SMPS. located a few feet fom the amp & is 100% electrially disconnected from the amp whenever the amp is on.

Play a smart RFI game !

Jack L

Hi

Bingo!

I think the only thing I like this power amp is "gone are the balanaced inputs" - gone are the discrete bipolar junction devices/op-amp chips which built up the differential balaned inputs - better sound !!!

As I said so many times in Sterephile forums before, equal impedance balanced audio transmission is historically for landline telephone transmissions & then for auditoriums/outdoor PA installation & recording studios where miles & miles audio cables are involved.

Technically, any audio cable runs shorter than 100 feet do NOT need balanced transmission. So balanced differential inputs for any home audios are REDUNDANT let alone the undue sound impairment by the balanced circuitry electronics & additional costs ! NOT audio consumers friendly at all.

Listening is believing

Jack L

The only thing notable about the PWR-3 and PWR+ is how poorly it compares to conventional Purifi 1ET400A builds despite LKV’s exorbitant prices. There is no magic here. He is buying the same Purifi amp module as everyone, but then goes and does things to it that add a bunch of distortion and poor measured performance. Among Stereophile measurements, the $2000 NAD C298 is the obvious pick for an apples to apples comparison since it also uses the same amp module. It mops the floor with even the $10,000 PWR+. This has nothing to do with using a SMPS in the PWR-3! The C298 has a SMPS and it doesn’t have any of the same problems.

The performance of Purifi is undeniable. LKV exists to coddle uninformed people who would otherwise not trust a mass-manufacturered, inexpensive, Class D (shudder the thought!) amp. LKV assembles them in New Hampshire, gives them that mysterious, home-brew audiophile look, and gives them reason to think it’s a special product with meaningful elements of the highly revered Class A topology, and then jacks up the price. Then dummies who intrinsically trust an ugly, unoptimized, $10,000 amp from a company no one’s ever heard of before over a proven groundbreaking $2k unit from NAD buy it and know at least their neighbors will never see another one like it.

Anyone considering an amplifier utilizing Purifi Eigentakt technology...

Purifi is selling a newer Eigentakt module, 1ET7040SA. Compared to the 1ET400A the 1ET7040SA is capable of delivering higher maximum peak output current (much also depends on cooling/heatsink), 40A rather than 25A. That may be useful in driving loudspeakers exhibiting low load impedance.

There are amplifiers currently available for sale (and for review) which utilize this newer module. For example, VTV is offering a dual mono two channel amplifier (in one shared enclosure) which uses two 1ET7040SA amplifier modules, two Hypex SMPS1200A400 power supplies (which VTV marketing highlights as the same power supplies utilized by Purifi to demonstrate their module), a multitude of choices among different input board options, and various options in chassis connectors for input and ouput, and is currently priced from $1,893.00 to $2,888.00 depending on selected options. They also offer monoblocks at a higher price (for two) due to the two separate enclosures, and those are currently priced from $1,072.00 to $1,619.00, depending on selected options. Notably and disappointingly missing among VTV's input board options is Tom Christiansen's Neurochrome input board, which is well engineered with a goal of high purity, not toward adding a different nonlinear sound characteristic.

I would like to see Stereophile review that VTV amplifier or the similar separate monoblocks and compare the various input boards (so would need to enlist a reviewer capable of swapping those boards, and have VTV's assent). I would also like to see VTV offer the Neurochome input board as one of the options.

Also, Purifi may soon be selling power supplies (not Hypex power supplies), so look for those, and look to see what capacitors are utilized in those (differences in operating life, etc.).

This is not SPAM. I have no financial interest in any of this, have no affiliation with any of those selling these amplifiers and components.