Integrated Amp Reviews

Western Electric Type No.91E integrated amplifier Specifications

Sidebar 1: Specifications

Description: Single-ended 300B integrated amplifier. Tube complement: One matched pair Western Electric 300Bs, one pair WE ECC81s. Output power: 20Wpc into 4 ohms (THD 10%; 10dBW), 16Wpc into 4 ohms (THD 5%; 9dBW), 14Wpc into 4 ohms (THD 3%; 8.5dBW). 20Wpc into 8 ohms (THD 10%; 13dBW), 16Wpc into 8 ohms (THD 5%; 12dBW), 14Wpc into 8 ohms (THD 3%; 11.5dBW. Phono sensitivity, MM (10W into 4 ohms): 0.75mV; MC (10W into 4 ohms): 70ÊV. Phono input impedance (MM): 47k ohms, 100pF. Phono S/N ratio, MM (10W into 4 ohms, input 5mV): 83dB(A); MC (10W into 4 ohms, input 0.5mV): 73dB(A). Phono frequency response: 30Hz–20kHz (RIAA ±0.5dB). CD S/N ratio (10W into 4 ohms, input 0.5V): 101dB(A). CD sensitivity (10W into 4 ohms): 0.27V. CD input impedance: 20k ohms. CD frequency response: 15Hz–32kHz (–3dB). Bluetooth CODECs supported: BC, MP3, AAC, FastStream, aptX. Bluetooth sample rate (adaptive): up to 96kHz (aptX), bit depth up to 16 bits. Bluetooth frequency range: 20Hz–20kHz. Bluetooth S/N ratio: 96dB. Power consumption: (operation/standby) 160W/0.3W. Operating voltage: 100V/115V/230V, 50–60Hz. Power fuse: 2A, slow-blow.
Dimensions: 18.9" (480mm) W × 15" (300mm) D × 11.1" (280mm) H. Weight: 49lb (22.2kg).
Finishes: Nickel, champagne, black. Chassis: Machined aluminum.
Price: $14,999. Warranty: three years. Number of dealers: 17 worldwide. In US, sold direct and through dealers.
Manufacturer: Western Electric 201 West Gordon Ave. Rossville, GA 30741. Tel: (404) 352-2000. Email: info@westernelectric.com. Web: westernelectric.com.

COMPANY INFO
Western Electric
201 West Gordon Ave.
GA 30741
info@westernelectric.com
(404) 352-2000
westernelectric.com
ARTICLE CONTENTS

COMMENTS
JRT's picture
Submitted by JRT on October 21, 2022 - 12:24pm

I think that this should be mentioned as eventual replacement of the tubes is part of the expenses in using the tube amplifier (and the life might be shortened by operation in class A2).

The prices direct from Western Electric for new 300B triodes are currently, $699 each for a single (1) tube, $1499 for a matched pair (2), and $3099 for a matched quad (4). This amplifier uses either two single tubes (unmatched) or a matched pair. The latter would cost $101 more, but might offer better measured performance, perhaps also audible.

JRT's picture
Submitted by JRT on October 21, 2022 - 1:32pm

When the preamplifier portion eventually fails, and if repair is impracticable (perhaps some future capacitor leakage destroys an internal layer on the circuit board, or a monolythic integrated circuit fails after it has gone obsolete, out of production, out of support, becoming too difficult to source a replacement component to feasably effect a good repair), then the separate preamplifier could become dumpster fodder while the tube amplifier(s) continue a very long useful life needing occasional replacements of tubes and perhaps also capacitors.

Integrating the components saves build costs (reduces number of separate enclosures, reduces assembly labor, reduces packaging, perhaps also reduces number of separate internal power supplies, etc.). I would argue that it does not save any footprint because a matching separate stereo preamplifier could be designed to stack under the separate stereo tube amplifier. But these are not separated, and I would suggest that the integration is almost all about cost reduction, and in this $15k price level, there should be more than enough budget to avoid the real compromise of excessive integration and the reduction in system flexibility and the reduction in system reliability which both result from that compromise. There should be more than enough in that budget to afford separate components.

JHL's picture
Submitted by JHL on October 21, 2022 - 1:39pm

Simply breathtaking. Any passing knowledge of super-triode amps shows this item to be absolutely top-shelf. Thank you for covering it.

(But tubes wear out omg and it just must be a two-piece sez JRT, lol)

Jack L's picture
Submitted by Jack L on October 22, 2022 - 2:05pm

Hi

"Super triode" topology is a totally 'revolutionary' audio amp design using a triode as active negative feedback device from the plate (P) of the output power tube to its grid, claimed to improve the linearity of the power tube, hence better sound. This topology was invented by Shin-ichi Kamijo, a DIYer of Japan some 30 years back.

I doubt very much such "super triode connection" (STC) topology ever employed by any brandname amps.

Or you mean something else ?

Jack L

JRT's picture
Submitted by JRT on October 22, 2022 - 3:21pm

Some decades ago, while designing toroid output transformers for Plitron, Menno van der Veen published at least one whitepaper that included information on his "Super Triode", and he trademarked the phrase. And his is different from Shinichi Kamijo's "Super Triode Connection".

It is described in the paper at the link at the bottom of this post. In that paper, see circuit 7 in figure 1, which is similar to Ultralinear, except with the addition of separate cathode feedback windings (aka cathode feedback tapes) connected to the cathodes with phase such that the cathodes receive negative feedback from the output transformer.

https://pearl-hifi.com/06_Lit_Archive/14_Books_Tech_Papers/Van_der_Veen_Menno/New_Push-Pull_Tube_Amps_Orig.pdf

Jack L's picture
Submitted by Jack L on October 22, 2022 - 2:59pm

Hi

What are Plitron toroidal transformers to do with "Super triode"???

Triode is a glass tube & transformer is a solid metal impedance converter ???

What is the logics there ?

Jack L

ejlif's picture
Submitted by ejlif on October 21, 2022 - 10:23pm

whenever I read about tube amps that have all the slam and bass of solid state my thought is why not just get solid state then? I like a tube amp because it sounds that way. I would be interested to compare this amp to the Feliks Arioso 300B. I have that amp and the Decware Zen triode. The Feliks is no wimp and I would say it probably sounds a little bit like solid state in some ways even. To me if you want a tube amp you want zero listening fatigue. To me that is what the hassle of tubes is all about. What you say about the Shindo stuff that sounds very intriguing.

Jack L's picture
Submitted by Jack L on October 22, 2022 - 2:12pm

Hi

It depends on the design, my friend.

My design/built power amps sound fast, punchy & see thru-transparent like a quality SS amp, yet retain tube's melodic & emotional sonics that SS lacks !

Listening to triodes is believing

Jack L

remlab's picture
Submitted by remlab on October 22, 2022 - 8:46am

..would probably match nicely with these

JRT's picture
Submitted by JRT on October 22, 2022 - 11:01am

... Musical Fidelity 750K Supercharger monoblock power amplifiers (circa 2008). Those booster amplifiers are designed to provide a benign load impedance while also boosting power output to something capable of driving conventional loudspeakers to usable SPLs at usable propagation distances with unclipped signal crests (clipping does not sound good, regardless the technology used to provide signal gain), and with low enough nonlinearity such that the nonlinearities of the tube amplifier dominate the sonic character of the signal gain.

JA1 reviewed a pair:
https://www.stereophile.com/solidpoweramps/1208mf/index.html

Jack L's picture
Submitted by Jack L on October 22, 2022 - 3:14pm

Hi

Yes, that why trioide sounds better than another other active devcies like pentodes, tetrodes, & all bipolar junction devices, e.g. transistors, FETs, op-amps. Only triodes get truly linear signal transfer curves vs kinked/kneed transfer curves of all other devices.

My skeptical ears hear the sonic difference particularly at high climax volumes !!!

Listening to triode is believing

Jack L

Jack L's picture
Submitted by Jack L on October 22, 2022 - 3:49pm

Hi

Nope, it is not the "booster amps" "to provide benign load impedance" for driving louspeakers.

It is the "booster amps" should be designed enough to handle the roller-coasting 'hostile' load impedance (R+C+L) of any loudspeakers.

The bench test data provided by most, if not all, brandname amps has been based on resistive dummy loads instead of a loudspeakers since day one decades back.

The Sterophile lab bench-tests any amps under review using simulated loudspeaker loads instead of resistive dummy load, providing measureed data more realistic to the realworld situation.

Jack L

JRT's picture
Submitted by JRT on October 23, 2022 - 12:29am

The SET amplifier is not load invariant, operates with better linearity if driving a benign constant resistive load impedance. The input to the booster amplifier provides a benign constant resistive load impedance to the SET amplifier driving it.

The output of the booster amplifier drives the loudspeaker and is much more nearly invariant to the load presented by the loudspeaker, if operated within the design limits of the booster amplifier.

Jack L's picture
Submitted by Jack L on October 23, 2022 - 6:20pm

Hi

First off, why NEED a "booster amp" for a SET amp ????

I doubt very much you have auditioned in depth the sonic quality of a SET - melodic & emotional music quality that noooo other tube & SS output power stage designs can match !!!!!

We are talking music QUALITY not quantity, OK ???

So why add a booster amp to ruin the musicality of a SET ? What is your logics ?????

Adding a booster amp to the loudspeaker output of the SET just amplify the SET/programme sources harmonic, phase distortion & noise level. You are opening a hugh can of worms, pal !

So why bother to go for a SET in the first place? Just get a tube power amp with pentode push-pull power stage to deliver much higher power to push your loudspeakers instead.

Sorry, I don't think you appreciate the distinct musicality of a SET at all !!!!

Technically, you think the 8-ohm loudspeaker output of the WE300B SET would be happy to load a typical 50K-100KR input of a booster amp ???? FYI, the best coupling impedance ratio should be 1:10, OK !

Back to the booster power amp, tube or SS respective, it still has to work with the ever-changing complex impedance (C+L+R) of any loudspeakers hooked up to it. Same destiny of a SET! So what if it were operated "within the bench-tested design limits of the booser amp" ????

Good fascination ! Please get real !

Listening to SET is believing

Jack L

Jack L's picture
Submitted by Jack L on October 22, 2022 - 6:12pm

Hi

Yes, "loop negative feedback" should be not be used in any amps, including phono RIAA EQ, & power amps for best sound.

K. Micallef quoted "91E has zero negative feedback both local & global".

So is there actually any loop NFB in this amp at all per yr captioned quote ?

Jack L

directdriver's picture
Submitted by directdriver on November 3, 2022 - 12:11pm

"The Western Electric division's own creations include the Orthophonic phonograph, the Westrex cutting-lathe system, the 300B vacuum tube, considered by many the greatest triode power tube ever made, and the 1936 WE 91A single-ended triode (SET) integrated amplifier, which powered cinema systems across the country."

The original WE 91A, I believe, was used as a monitor amp for the projectionist to hear what's playing in the theatre while he's in the projectionist booth. The 91A was not intended to drive speakers for the movie audience.

Jack L's picture
Submitted by Jack L on November 3, 2022 - 2:46pm

Hi

Agreed.

In 1940 cinema era in USA, the cinema/auditorium loudspeakers started to use the then newly invented efficient permanent magnet: "Alneco" in the speaker unit drivers.

The tube amps also started to use the then newly developed power tubes, e.g. KT66 & 6L6 in 4-6 parallel push-pull configuration to provide up to 40-60 watt "hugh" power for all cinema/auditorium sound systems across the country.

No way WE91A low output power was powerful enough to drive the cinema sound systems back then.

Jack L

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