Valvet A4.5 Class-A Mono Power Amplifiers (Pair)

The Valvet A4.5 is a pair of Class-A monoblock power amplifiers in push-pull design, one chassis per channel.

Unlike the single-ended models E3 and E4, the A4.5 operates in push-pull mode: a pair of transistors per amplifier shares the amplification, allowing significantly more power while still remaining pure Class-A operation. The signal path stays capacitor-free from DC up to 100 kHz – extremely short pure-silver connections instead of components that could filter or colour the signal.

Why the Valvet A4.5?

Because it combines Valvet's Class-A philosophy with usable everyday power: 60 watts into 8 ohms and 100 watts into 4 ohms per monoblock suit far more speakers than the single-ended models. Each monoblock brings its own 500 VA toroidal transformer, four ultra-fast 60 A diodes and four Supertech TTN filter capacitors – supplied as a pair, so both channels are identical from the factory.

What you hear

Class-A-typical calm, controlled sound with plenty of bass foundation – but with the extra headroom that push-pull circuits offer over single-ended designs. Optionally bi-wirable WBT-NextGen terminals let you connect speakers with separate tweeter and woofer connections directly.

Who is the A4.5 suited for – and who isn't it for?

Straight talk: the A4.5 suits far more speakers than the single-ended models E3 and E4, simply because it brings more power and control. If you're after the very particular, very direct sound character of pure single-ended Class-A amplifiers, you deliberately reach for the E3 or E4. If instead you're running a setup with more demanding or less efficient speakers, the A4.5 is the right choice.

Our verdict

The A4.5 is the all-rounder of the Valvet power amplifier family: pure Class-A circuitry with enough power in reserve for most speakers. Tell us which speakers and which room you're working with, and we'll clarify whether the A4.5 or one of the other models suits you better.

Technical data – Valvet A4.5

• Type: Class-A monoblock power amplifiers, push-pull, sold as a pair
• Amplification principle: a transistor pair per amplifier
• Power per monoblock: 60 W into 8 Ω / 100 W into 4 Ω
• Gain: approx. 26 dB
• Inputs: WBT-NextGen RCA and Neutrik XLR
• Input impedance: 50 kΩ
• Outputs: WBT-NextGen speaker terminals, bi-wiring optional
• Power supply per monoblock: 500 VA toroidal transformer, 4 ultra-fast 60 A individual diodes, 4 Supertech TTN capacitors
• Signal path: capacitor-free (DC up to 100 kHz), extremely short pure-silver wiring
• Housing: aluminum, 12.5 mm front panel, black or silver anodized (special gold finish on request), chrome only on explicit request
• Dimensions per monoblock (W×H×D): 23 × 11 × 31 cm
• Unit: pair (2 chassis)
• Origin: handmade in Germany

Frequently asked questions

What distinguishes the A4.5 from the single-ended model E4?

The A4.5 works in push-pull design with a transistor pair per amplifier and delivers 60/100 watts, the E4 in single-ended design with just one transistor and delivers 12/20 watts. Both stay pure Class A, but differ clearly in power reserve and sonic character.

Is bi-wiring possible?

Yes, the WBT-NextGen speaker terminals are optionally designed for bi-wiring. This lets you wire speakers with separate tweeter and woofer connections directly.

How long is the delivery time?

The A4.5 is built in small series in Germany; delivery time from the factory is usually several weeks. Ask us directly for the current schedule.

Which speakers suit the A4.5?

Thanks to the push-pull circuit and 60/100 watts of power, it suits a much broader range of speakers than the single-ended models E3/E4 – from medium to lower efficiency. For very difficult loads, we're happy to advise you in detail.

Why buy the Valvet A4.5 at HD Zürisee?

Because Class-A monoblocks only show their full potential with the right preamp and matching speakers. We advise you in Wädenswil on the system combination and handle installation with our own technician.

Goes well with: matching preamplifiers, floorstanding speakers and the right cables.