Home > References > De havilland 845 amplifiers for acoustic guitars

De havilland 845 amplifiers for acoustic guitars

Tenor Audio 75Wi Mono Amplifiers. Use Less noisy and "more intimate"-sounding when used without a preamp; put out enough heat to raise the temperature in Marc's listening room ten degrees. Value "Seek out a pair, but have your checkbook ready. Since then, Tenor has shown at T.


We are searching data for your request:

De havilland 845 amplifiers for acoustic guitars

Schemes, reference books, datasheets:
Price lists, prices:
Discussions, articles, manuals:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.
Content:
WATCH RELATED VIDEO: Echomaxx E2 40w acoustic guitar amplifier - unboxing, tests \u0026 review

Stereophile | January 2017 Issue


April 15, Progress, by definition, is forward motion, even in audio. But Kara E. Chaffee, chief engineer of deHavilland and for ten years known for the manufacture of superb, low-powered, single-ended-triode SET tube amplifiers, recently had an epiphany about a vintage, push-pull set of class-A monoblocks.

About 18 months ago, a reviewer friend not I asked Chaffee to restore to operating condition a pair of original Fisher 50A mono amplifiers, a model developed in She took them apart and, after getting completely familiar with their schematics and design, put them back together, this time with a bit more capacitance in the power supply. She came to see that the design was not precisely vintage, if vintage meant an overripe midrange, high coloration, and woolly bass.

She sat down at her drafting board she still uses a physical drafting board and mechanical pencils , began to draw parts, schematics, and values, and soon got the idea that she could manufacture this amp herself -- upgrade its parts, clean up its looks, and recapture its sound for the contemporary audiophile.

To do this, she uses better grades of materials -- a milled aluminum chassis, a machined top plate and transformer endcaps -- and has beefed up the circuit with more current four times as much in some places and made some modifications.

For sonic reasons, she replaced the original 12AU7 tube in the second gain stage with a 6CG7. She used a Lundahl interstage transformer to produce better bandwidth than the original, and put new old stock NOS Russian and Jensen paper-and-oil capacitors in the signal path instead of the paper-only caps Fisher had used.

Finally, she replaced the original output tubes "which no one loved," she said with reissue Genelex Gold Lion KT88s, which would operate in class-A and in triode mode -- just like the originals. The result was one pair of deHavilland Fisher 50A prototypes, rated minimally at 40Wpc in push-pull. Chaffee also showed them at the Rocky Mountain Audio Fest, to acclaim from attendees and the audio press alike. A pair fit comfortably side by side in a conventional audio rack with usable space of about 20" wide or so.

Each can also go next to the speaker it drives, in a more conventional monoblock placement. Very handsome, the 50A is available in natural aluminum, or with anodized black sides and a natural silver top plate.

Each 50A has nine tubes: two KT88 output tubes , KT90, and 6L6 tubes are drop-in replacements , one 12AU7 for the first gain stage, two 6CG7s one for the second gain stage, one for voltage regulation , two 6CL6s for the interstage current drive, and two 6CK3 rectification tubes.

The Fisher 50A operates in class-A, push-pull, triode mode. How much in class A? One retro feature that Chaffee retains as stock is the barrier strip on the rear panel, with its 4- and 8-ohm taps, but she also offers the option of Cardas binding posts with either the 4- or 8-ohm tap hooked up, depending on customer preference. With the Cardas posts, the ohm values of the taps can easily be converted, if any change is needed, with a simple solder job of one wire at the back of the chassis interior.

My review pair had the Cardas binding posts set for the 8-ohm taps. Also on the rear are the input for a 15A IEC power cord, a screw-in holder for a 5A fuse, and a ground-float switch. This switch, a feature on all deHavilland amps, is used mainly to shunt the ground so that it flows only through the RCA interconnects, eliminating potential ground-loop problems.

It can be used or not, depending on individual circumstances, but there can be an audible advantage in floating the power-line grounds. I did so, using my interconnects for both my signal and ground-path return. On the top of the 50A, near the front, is a simple on-off switch. Sitting between the two transformer covers, about midway and to the left side, is an onboard meter and switch for setting the bias of the output tubes.

The top plate is perforated with two separate fields of air holes for ventilation -- one, measuring 3"x 3", near the 6CK3 rectifier tubes at the front end, and another, measuring 2" x 3", to the right of the bias meter. There is also a line of small holes between the transformer covers along the top left side of the amp.

It all adds up to a look of functionality dressed with taste. To bias the 50A, you simply fire it up and, after letting the rectifier tubes warm up for 20 seconds, flip and hold the bias-meter switch. This activates the meter, which reads the output current passing through the KT88s. Chaffee sets the bias at mA, which is marked by a bold red line on the scrolled meter face. The bias can be adjusted perfectly with a black knob next to the meter. During the review period, most of which fell during the Oregon winter, I appreciated the moderate doses of heat with which the 50As cheerily warmed my study.

But as winter turned to spring and outside temperatures rose above the low 70s, these class-A amps raised the temperature enough that I had to open a couple of windows to cool the room. The deHavilland Fisher 50As sounded best after about 30 minutes of warmup. II or Mercury preamp. The Fishers were each plugged into a Cryo-Parts power strip with Cardas Golden Reference power cables, and the strip itself was plugged into the wall with another Golden Reference.

I have two 15A dedicated lines, both with Oyaide R1 duplexes. The room is treated with sound panels from Acoustic Sciences Corporation; bookshelves line the right wall, shelves of LPs the left. The Von Schweikert VR5s are toed in about 3", so that the tweeter axes fire slightly to the outside of my ears in my standard listening position.

Instead, I thought of tonal density and weight. The 50As created an audio tapestry -- an overall lavishness and permeable luxuriance open at times to stunning accents and sparkle, anchored by the gorgeous weight of its own fabric. Yet nothing seemed out of balance or over-the-top -- no artificial "detail" bordering on brashness, no thickened and overemphasized midrange masking a missing top end or bass, no too-forward treble or bass heaviness at all.

The Fisher 50As could capture the weight of symphonic music, as well as all the snap and sizzle of a salsa band. Or, in the Allemande from Suite 2, it could be dark, mordant, and brooding, with a sinuous and aching melodic line. Whatever the case, the character, pitch, resonance, and speed of vibration of each string was movingly evident and palpable through the Fisher 50As.

In my experience, the sound of the violin is one of the hardest to reproduce -- many audio systems render it as all too glossy, impenetrable in its silkiness, creating spurious homogeneities of tone that belie the wide palette of timbres and musical emotions the instrument can convey. The orchestra piped, plucked, and bowed through a decorous, dancelike accompaniment that also demonstrated the vibrancy and grace of the Fisher amps. The first number, "In My Solitude," has a resonant and liquid piano intro by Ellington that gives way to comping as the horn section swings into the tune.

Via the Fishers, the tune was sweet and warbling, with fabulous tonal weight and authority throughout. And so it was throughout the entire LP: full, saturated saxophones; a brilliant and brassy trumpet; fabulously rich and weighty horn choruses; and bass thump and drive. Hoots, swoops, sustained shouts, warbles -- Cocker had them all. Stainton fills in on bass, piano, and organ as the other two sidemen lay down a funky blues walk of a start, piano and bass on the beat, while Cocker croons a bit before the shouts and hollers come, interrupted only by the tiny canticle of a solo-piano bridge.

In each passage, the sounds came through with shoulder-shaking immediacy, the music calling out to make my poor, beer-chugging, fiftysomething, Friday-night body move. For contrast to this vintage rock, I put on some acoustic piano music. This was something the Fisher 50As excelled at, producing a vibrant, deeply resonant, harmonically rich sound no matter the format.

When the full orchestra joined in the first tutti , a Jovian thrum and weightiness came through, evoking a sweet gravitas that only Mozart can. The Fisher 50As did especially well with the bass viols in the first movement, Allegro maestoso , their lightly bowed notes sonorous and fulsome, filling the woofers of the right speaker with a warm vibrance that seeped away into the books of poetry and philosophy that line the shelves along that wall.

The Fishers rendered all of these, and each of the orchestral tuttis as well, with a fine and formidable ease, never once losing resolution, force, or grace. So far, so good -- tone, tone, tone.

What about imagery, soundstaging, and that modern thing called PRAT pace, rhythm, and timing? The Fisher 50As presented what could have been a welter of percussion instruments and all their various timbres with fine imaging, a good lateral soundstage, tremendous PRAT and sparkle, and complete alacrity and precision, along with their characteristically saturated tone. Then the dance begins with a series of sharp, pulsing, bowed strokes from the strings that are full of eccentric, thrilling accents and stirring fortes.

After the first fanfare and initial blast of bass-drum strokes, a spinning drama builds among the horns, strings, and woodwinds, which share and alternate in taking the theme.

The Mock Abduction culminates in assaultive, elephantine crescendos -- the horn, woodwind, string, and brass sections swell to the edge of shrieking cacophony, this rapidly followed by a series of thunderous strokes on the bass drum that could be the death of an ordinary amplifier -- if not in tonal accuracy, then in the congestion of timbres; if not in a shallow, shrunken soundstage, then in the faintness of bass slam and speed. When I listened at moderate levels, my handheld RadioShack SPL meter measured the peak output as topping out at 95dB on the bass-drum strokes, confirming what, at that first stroke the first time through, my gaping mouth was already saying: Wow!

A question remained about voices. This is one of the great soprano arias, and de los Angeles sings it with moderate vibrato and long, full, expressive notes. With the Fisher 50As, I felt as if I was hearing the full creature -- all of the loveliness of de los Angeles, with no plaintive tinniness or shriek. Her top notes were full of dynamism, whether in attack or diminuendo. The Air Tight ATM-2 stereo amplifier, itself an audio classic, albeit a more recent one, has been my reference for over two years.

There was also a slight overdriven quality to the treble: a decided lack of silkiness and a somewhat grainy top end. I would have liked more body and midrange warmth, too. My notes on listening to some of the same orchestral recordings and piano concertos mentioned above tell me that, through the Air Tight, the violins were slightly glossy though not bleached , timpani strokes were soft, and timpani rolls were muted, more midrangey than deep bass.

To say that I was dissatisfied is an understatement. But with operatic and choral voices, particularly tenors and sopranos, the Air Tight was superb -- clear, clean, extended highs, pretty on top, and very liquid. Yet, overall, this was a no-brainer -- whatever the Air Tight ATM-2 could do, particularly with voices, the Fisher 50A monos could do at least as well. And what the Air Tight could not deliver -- tonal weight, midrange warmth and body, bass slam and definition, a full sonic palette -- the Fisher 50As delivered in spades.

If your speakers can get by with relatively moderate power 40W nominal, perhaps 45W at clipping , you should strongly consider auditioning the deHavilland Fisher 50A monoblocks.

Their combination of top-to-bottom balance, clean and resolving highs, magnificent bass and slam, articulate speed and PRAT, and gorgeous brocade of sound, seems to me very hard to beat. Garrett Hongo garretth ultraaudio. Warranty: Three years parts and labor. Comparison and conclusion The Air Tight ATM-2 stereo amplifier, itself an audio classic, albeit a more recent one, has been my reference for over two years.


Tannoy System 15 DMT II Studio Monitors

Discussion in ' Audio Hardware ' started by Panneauman , Nov 23, Log in or Sign up. Steve Hoffman Music Forums. Location: Pittsburgh, PA. Jay F , Nov 24, Location: Minneapolis. Great amp.

The combination of your speakers and that class A amp is beyond my dreams. tape via a modified Technics R2R and DeHavilland repro head stage.

Your Favorite Amplifier


I was so impressed by the amplifier that I made the decision to write what was called Part I of this three-part review. The Pass Labs XA To be honest though, only four of them ever made me think they might be as good as my beloved Wavac ECB. Of the three transistor amps, the First Watt SIT-1 sounded the most like the Wavac ECB and I would be the first to admit that if I were buying them new I could not justify spending three times as much for amps that sounded so much alike. Of the four amps the ASR sounds the most different. That could be good or bad continuing on your speakers. All four are great amps, though. The ASR is the fastest and most transparent amplifier I have ever heard. Its speed and transparency extends into the frequency extremes. This results in the tightest bass with the most slam I have heard in my reference system.

Red Rock Audio Renaissance Monoblock Amplifier Review

de havilland 845 amplifiers for acoustic guitars

This review page is supported in part by the sponsors whose ad banners are displayed below. Secondary: Outlaw Audio RetroReceiver. Secondary: Zu Audio Druid Mk. Secondary: Analysis Plus cables and interconnects.

April 15, Progress, by definition, is forward motion, even in audio.

Kinki Studio EX-M1 200 WPC Integrated amplifier


Sp in a few LPs with Jonathan Val in , who is savor in g some tasty. Class D amps are all the rage. Chris Martens listens to another offer in g in. Reviews of 11 new CDs, in clud in g the latest from the Flam in g Lips,. Bldg G, Aust in , Texas

in this issue

To give you an idea, I go thru amps like nothing, but the speakers stay. My god, how good does it get?! Drums sound like drums, pianos sound like pianos, etc. I have to listen to my whole library again! What a soundstage. Every instrument and voice occupied and owned its own space in the given composition.

Cary and deHavilland are two other audiophile brands that have also created The effect was such, that the acoustic guitars in the Master Music XRCD

David, aka Grumpy, needs our help. Great news. David is home! It was quite the ordeal to get him home and into the house, but it is done.

General Comments I like them alot! Have been using the Shunyata Python Helix Alpha's. Upon comparison the coincident appear to be a little more musical and engaging used on my power amps. As always, thank you for the great service and passion you share for music. MH Langley, B.

Rectification: two separate tube rectifiers for HV. There is also copper plate version.

KEF R Loudspeakers. KEF Reference 1 Loudspeakers. Focal Sopra No2 Loudspeakers. Cocktail Audio X40 Music Server. Paradigm Founder Series F Loudspeakers. Yamaha A-S Integrated Amplifier.

We make every attempt to combine the unique, with the well established to form synergistic home entertainment systems. Auditions take place in a comfortable, relaxed environment The Concept is simple, I love music!




Comments: 2
Thanks! Your comment will appear after verification.
Add a comment

  1. Matias

    I must admit, the one who wrote the nishtyak was sprinkled.

  2. Oswin

    You must say this - the mistake.