SPL Passeq Mastering Equalizer Red

In the PASSEQ we have revived the concept of the passive equalizer that was used in the 50’s and 60’s. The charming sound of this vintage technology combined with the modern 120V technology results in a very special equalizer.

Only one filter​:
All control functions are part of only one passive filter.
There are three frequency ranges:
Low Freq / Mid Freq / High Freq
Each with a cut control on the left and a boost control on the right.
In the middle is the output control.

Design:

A passive filter has no amplification stages. It can therefore only be lowered. If one frequency is to be boosted, all the others must be lowered. Behind the filter there is a stage that makes up for the lowered overall level. Since low noise is particularly important here, since up to 20 dB can be made up for, the 120V technology comes into its own.

The entire passive filter (variable resistor, capacitor and coil) provides a very nice sound characteristic. Besides the choice of components, the charging behaviour of the capacitors and the saturation behaviour of the coils play a major role in this. The resulting relative inertia compared to potentially very fast active filters is the reason for a pleasant, musically advantageous sound characteristic. We would choose smoothness and transparency as well as strikingly silky highs and pithy basses as a description that suits our perception.

During fine-tuning, through component selection, in countless listening sessions, the emphasis was on achieving the most musical sounding curves possible, which, for example, need fear no comparison with a Pultec EQ from the 1950/60s. Only without all the disadvantages of a 60 year old original, such as the very high background noise, but above all the very limited frequency selection.

Another highlight of the PASSEQ is the HF+ band, which has been extended by the frequencies 25 kHz and 35 kHz and sounds so incredibly good that you don’t want to switch it off.

US and EU parcels ship via UPS, ETA 1-7 working days from pickup day zero. That also applies to most locations worldwide.

All shipments are fully insured.

Bigger shipments requiring pallets or custom made crates ship to US, CA, JP, CN, AU and other outside of EU locations via DHL Air Freight, ETA is normally approx. 7-14 working days from pickup day zero.

Big shipments inside EU ship via different freight companies, recently mostly via ACE Logistics. Freight forwarders can use different courier companies for deliveries to final destinations.

Palletising and crating time can vary depending on the size of the shipment and packaging queue. We pack all our shipments with great care.

You are most welcome to pick your order up yourself from our Retrosonic Pro Audio showroom, studio and warehouse in Tallinn, Estonia.

We ship worldwide – contact us for a personal shipping quote or any other questions.

VAT (Value Added Tax) can be deducted if you have a company with a valid EU VAT number or if you're based outside of the EU. Non-EU buyers pay all and any import tax and duty as regulated by their local customs.