It all started when…
The UI-55 transformer is a traditional stacked alternating multi-layer wound transformer using custom nickel blended laminations with novel ‘tape and layer’ techniques found in hard-to-source transformers from Peerless and Freed.
After the CEQ’s initial output transformer winder, Marvel Electric Co, Chicago (in business since 1954) folded and finally retired the family business in April 2020, a transformer that had been in R&D several years back went to the grindstone and winds were finished in the ensuing 9 months of continued lockdown.
The transformer is dual-bobbin on a U-I lamination stack, which allows for greater inter-layer capacitive seperation than ‘EI’ styles. This also allows a ‘repeat coil’ type of winding, used since the ‘Western Electric’ days.
Beyond the specs, and not a direct clone of any one transformer model, the UI-55 was tuned for the ‘magic tone’ of this transformer winding and layering style which were not found to be offered commercially today by other transformer makers. Simply put: it was hard to believe that this wasn’t being done. Now, here it is…
Lead Hookup Diagrams and Manual here.
UI-55 Specs:
Bandwidth: +/- 0.5dB 10-80khz into >2k, 14-40khz into 600 ohms
THD: 20hz 1% at +19dBu (matches classic Peerless 1:1 transformer specs), terminated with 2k
No ‘zobel’ network needed for large ultrasonic resonances, 2k recommended termination impedance
Wire as 1:1 unity gain or 2:1 / 1:2 ‘step up/step down’
Custom nickel lamination blend alloys
Stock output transformer in the CEQ 6 Band Passive Mix Equalizer
Available individually for custom builds, OEM, restorations and upgrades for consoles, preamps, summing, ‘transformer’ boxes, etc.
Recommended for any transistor low source impedance output stage and tube cathode-follower AC coupled output stages
Wire lead only. Non-potted for best tone.
Stacked alternating layer winds. Not a ‘bifilar’ winding style. Cloth glass tape insulation between layers.