day-sequerra tuners

DaySequerra Tuners

Reference materials for owners and aficionados.

This page is a collection of reference material I've collected over many years, and is a supplement to the materials I've compiled on the original Sequerra Model 1 FM Tuner, click here.

I would suggest reviewing that material first, if you haven't seen it already, as the tuners described here are evolutionary descendants of that tuner.

Update 6/14/2018: FM Reference Manual, PDF format

David Day has graciously provided this draft version of the FM Reference manual. Note that it has not yet been updated for the FMR 25th anniversary edition. Click here to download.

UPDATE 10/2014: DaySequerra releases FM Reference 25th Anniversary Upgrade.

This upgrade replaces the CRT with an LCD display, and includes modifications to deal with sideband interference from Hybrid Digital (HD) radio, along with many other improvements. Details on the links below:

DaySequerra webpage: FM Reference 25th Anniversary Upgrade

Link to Stereophile magazine review

Above: The CRT scope tube as originally supplied in the FM Reference, before the 25th Anniversary Update.

Above: The same perspective after the 25th Anniversary Update showing the replacement LCD panel (rear view from the inside).

Above: Another view of the back side of the new LCD panel. In the foreground is a new post FM demodulation filter to deal with the self-noise generated by HD Radio.

UPDATE 9/2/12: FM reference - de-emphasis and 120v-240v power changes

The following is a note from David Gill showing how to modify the FM Reference for European de-emphasis and indicating how to change from 120V to 240V power (or vice versa). Thanks again to David for his gracious help to Sequerra owners world-wide.

UPDATE 7/10/11: Repairs and maintenance

For any Sequerra owner needing repair or maintenance services, I highly recommend David Gill (formerly of Gill Audio Design and Art Audio). He has the requisite knowledge base and documentation to successfully work on these complex tuners. His email is davidgill@cox.net

UPDATE 4/09: CRT Replacement Info for FM Reference

David Gill has researched and documented information on the replacement of the CRT for the DaySequerra FM Reference, but the info may be applicable to other Sequerra or DaySequerra tuners as well. Read his very informative paper here. Highly recommended!

UPDATE 5/5/09: New review!

Ken Kessler has reviewed the updated DaySequerra FM reference in HomeTheaterReview.com in January of 2009, click here.

Introduction and Background/History

I've compiled information here on the following tuners related to the original Sequerra Model 1. Each numbered item shown here has a detailed section below with photos, marketing materials and reviews.

1. Davidson-Roth FM Broadcast Monitor, introduced in 1986, was a near-exact copy of the original Sequerra Model 1 FM Tuner. David Day was president and chief engineer of Davidson Roth and acquired the rights to the Sequerra in 1984. It was later called the Day Sequerra FM Broadcast Monitor.

2. DaySequerra FM Studio Tuner, introduced in 1990 was an all new design, designed and built to a lower price point.

3. DaySequerra FM Reference. Introduced in 1991, this was a newly designed tuner, using the foundation of the original, but updating and adding functionality (details below). It was sold under the FM Reference name withOUT the spectrum analyzer function of the original Sequerra, and a version WITH that function was sold as the FM Reference Panalyzer, for an additional $8,000 (nearly triple the base price of $4,800, so that option was expensive!)

In addition, David Day has issued three updates to the FM Reference per the Stereophile article from 9/2006 (that article is shown below):

A. In 1998, the Classic Upgrade ($1,040), replacing the CRT, faceplate, and IF filters.

B. In 2006, the Signature Modification ($1,680), replacing the CRT again, adding circuitry to turn the CRT off at the front panel to lengthen its life, as well as replacing incandescant lamps with LEDs, upgrading the RF mixer and filters, and some work on the audio stage.

C. In 2014, The FM Reference 25th Anniversary Edition, replaces the CRT with an LCD display, and includes modifications to deal with sideband interference from Hybrid Digital (HD) radio, along with many other improvements. See links and photos at top of this page for more details.

I've also included some additional information of interest:

4. DaySequerra FM Urban Antenna, an indoor antenna

5. Additional marketing materials from DaySequerra, including a list of US dealers and pricelist from 1992.

1. Davidson-Roth FM Broadcast Monitor

This tuner appears to be a near-exact duplicate of the original Sequerra tuner (at least externally, with the same controls, inputs/outputs, etc.) as shown below. Note that the last versions of this tuner produced by the Sequerra Company were called "The Sequerra Model No. 1 Broadcast Monitor", but that the name Sequerra does not appear anywhere on this unit. The unit is, however, called the "Day Sequerra FM Broadcast Monitor" in the marketing material shown below.

Above: Davidson-Roth FM Broadcast Monitor, front view. Click to enlarge.

Notice the layout and labels are identical to the original Sequerra Model 1, including the Dolby button.

Above: Davidson-Roth FM Broadcast Monitor, rear view. Click to enlarge.

Again, it appears virtually identical to the original Sequerra except there is now a BNC connector for the detector output instead of an RCA jack, and gold RCA's are used.

"FM Broadcast Monitor" marketing materials:

Above: Davidson Roth FM Broadcast Monitor tent-fold flyer, front. Click to enlarge.

Note that this card was folded in the center to stand as a tent, so the top image appears upside down here and on the printed card. When folded, the tent card showed the wood cabinet version on one side and the rack-mount version on the other side.

Above: Davidson Roth FM Broadcast Monitor tent-fold flyer, rear. Click to enlarge.

"FM Broadcast Monitor" reviews:

Click here for a PDF review of the FM Broadcast Monitor from Stereophile Vol 12, No. 6 (June, 1989). Note that by this time the company was referred to as "Day Sequerra" not "Davidson-Roth".

2. Day Sequerra FM Studio Tuner

This tuner is significantly different from its predecessors. The internal circuitry is different, mostly on a single large PCB. The controls are also changed to reflect circuit changes: There are new selectable IF bandwith switches on the right (wide, normal and narrow), and on the left, switches for audio phase inversion and stereo contour override. Gone is the obsolete-before-it-got-started Dolby switch from the original Sequerra.

Above: FM Studio Tuner, front view. Note that the switch functions have been changed as described above.

This photo was copied from FMTunerInfo.com, a highly recommended resource for everything related to FM tuners.

Above: FM Studio Tuner, internal view.

Above: FM Studio Tuner, rear view.

"FM Studio Tuner" reviews:

Click here for a PDF review of the Day Sequerra FM Studio Tuner from Stereophile Vol 13, No. 1 (January 1990).

3. Day Sequerra FM Reference

This tuner is very similar (in controls, input/output connections, and general layout) to the FM Studio Tuner. It, however, incorporates a number of circuit improvements, including the option of the panoramic analyzer. These improvements are discussed in detail in the Stereophile review of 12/1991, see the link below.

Above: Day Sequerra FM Reference, front view. Click to enlarge.

Above: Day Sequerra FM Reference, internal view. Click to enlarge.

Notice the plexiglass over the high voltage circuitry, labeled to indicated adjustments.

Above: Day Sequerra FM Reference, rear view. Click to enlarge.

Notice that the layout looks identical to the FM Studio, and that the "FM Reference" label appears to be a stick-on label, as opposed to being silkscreened on - suggesting possible re-use of chassis parts originally intended for the "Studio" tuner.

Above: FM Reference Signature, rear view (the front view of the Signature version remains unchanged). Notice the new logo identifying the fact that this tuner has been upgraded with the Signature modification. See a review of the Signature Modification below.

"FM Reference" marketing materials:

Above: Day Sequerra FM Reference flyer - front. Click to enlarge

Above: Day Sequerra FM Reference flyer - rear. Click to enlarge

Above: Day Sequerra FM Reference Technical White Paper, cover only.

Click Here to see the entire document in PDF format.

"FM Reference" reviews:

To read the original Stereophile review of the original FM Reference, Vol 14, No. 12 (December 1991), click here for a copy at Allegro Sound. Very thorough and detailed review.

For the review of the Classic upgrade in Stereophile Vol 21, No. 1 (January 1998) click here.

The Signature Modification to the FM reference is reviewed below, from Stereophile, September 2006: