Deco Audio Pre Amps

Preamplifiers

Deco Bespoke Passive pre

Under our ‘Bespoke Modifications’ service we also make special products to order. Recently we have had increasing demand for simple passive pre amplifiers and so have decided to feature them here. The beauty with this is there’s no standard product - you choose the exact specification, from the housing used, through to the components used.

The average entry level build costs in the region of £200, but we don’t scrimp on the quality - parts often include an aluminium extruded case, silver plated socketry, our level one silver wiring and quality potentiometer. A cheaper ABS boxed version with a more basic potentiometer could also be made for an even lower cost if required. More deluxe versions with higher grade potentiometers or switched attenuators and our level two cotton covered silver wiring can cost in the region of £400-£600 depending upon exact specification.

For more information on costings please contact us with details including the number of inputs required, details of the system it will be used with and we will design a unique passive to your requirements.

Croft Acoustics Basic

The Basic is the entry level pre amplifier in the Croft Acoustics range and is quite astonishing value for money. It features three line level inputs, a line output (for a recorder or headphone amplifier) and a valve MM phono stage. As you’d expect from Glenn Croft the circuit is all hard wired (as can be seen in the photographs below) and made in the UK completely by hand. The design uses two ECC83 dual triodes for the phono section and one 5965 dual triode for the line stage and the power supply is well spaced from the audio circuitry to ensure low noise.

The sound it produces is classic Croft, on both line and phono input the sound is hugely captivating. I have found nothing that gets anywhere close to it at this price point - there’s a sense of rightness and toe tapping fun that is hugely involving, yet the sound never becomes uncouth or tiring. The fact you’re getting something that is hand made by the designer is the icing on the cake, and something of a real rarity at this sort of price level.

Croft Acoustics Micro Basic 25: £400

Audion Select 1.0

The Select 1.0 is a new passive pre amplifier from Audion that offers a very attractive and affordable way to control multiple sources. It is housed in a cut down version of the Premier chassis and naturally features the same aluminium and stainless construction materials. The classic Alps Blue Velvet is the volume pot is used and it’s combined with input switching for 5 line level inputs via the front mounted toggle switches. As shown in the picture below there are two pre amp outputs as well as a ‘Tape’ output which can be used to feed a recorder or headphone amplifier, so it also offers great flexibility when required (a little care with the impedances of connected items may be required if all the outputs are wired simultaneously, as a passive design means the source has to drive them all, but we can advise on this on an individual basis).

As you’d expect with a good passive pre amplifier the sound is open and natural, in fact it’s remarkably transparent for a product at this price level with no added grain to get in the way of the music. What’s more the absence of noise generating active devices means that it’s silent even when combined with very sensitive power amps and speakers.

Audion Select 1.0 passive pre amplifier: £475.00

Croft Acoustics Micro 25

The Micro 25 follows is the latest in long line of classic Croft pre amplifiers. This is the second model up in the range and is hard wired, hand made in the UK and unfussy in both appearance and usage. The Micro 25 uses three ECC83 valves for the line level stage and the MM phono input and has a auto mute on switch on that allows the valves to warm up for a few seconds before being fully operational (the LED changes from red to green to show when it’s ready to go).

I’ve long been a fan of Glenn Croft’s products and this latest range looks like it’ll be no exception - once I’ve completed running it in I will update this page, but even fresh out of the box it has all the Croft sonic hall marks that anyone familiar with their previous models will recognise - it has a great sense of rightness with an earthy, natural quality that lacks neither excitement or refinement.

Croft Acoustics Micro 25: £700

Croft Micro 25 version "R" Pre-amplifier

The Micro 25 “R” has a very substantial power supply, utilising two mains transformers supplying a regulated HT power supply with an 85A2 voltage stabilising valve. The line level stage and MM phono stage uses a total of five ECC83 dual triodes. More details to follow soon.

Croft Acoustics Micro 25 version “R”: £1,400

Audion Premier pre amplifier

The Audion Premier is valve pre amplifier that is available in two versions, a line level only model and a MM phono equipped version (as pictured here). Both versions features 6 inputs, have two outputs and a ground lift switch to ensure hum free operation in many different systems. The valves used are the Sovtek 6H23 (a 6922 equivalent) and the amplifier has a wonderfully open and transparent sound.

Audion Premier Line: £1,550

Audion Premier MM Phono and line: £2,150

Verdier Control B: £1,300 & £1,600

Verdier, famous for their superb turntables also produce a range of tube amplifiers.

This wonderful valve pre is available in two versions, both of which have (identical) very high quality phono stages, which by use of internal links allow adjustment for use with either MM or MC cartridges (via high quality internal step up transformers).

The difference between the two models is in the line stage, on the cheaper model (costing £1,300) this is passive and on the dearer version (£1,600) it is active. We recommend the active version as all conventional passive pre’s have a tendency to lack ultimate dynamic expression and are also very choosey about the type and length of the interconnect cables used.

Both versions use external power supplies to ensure low noise, and can be upgraded with a regulated valve power supply (pictured below) for an extra £1,430.

Music First Audio Copper TVC Classic pre amplifier: £1,920

We’d been eagerly waiting for the launch of the Music First Audio passive magnetic (or TVC, short for transformer volume control) pre amplifier ever since we learnt of its inception late in 2001.

The reason we were so excited about this pre is that it offers the benefits of passive pre amps without many of their flaws - conventional passive pre amps tend to squash dynamics and roll off treble, especially when long interconnects are used.

Unlike conventional pre amplifiers which use potentiometers for attenuation the Music First Audio preamplifier uses a transformer instead, which has the benefit of isolating and impedance matching sources and power amplifiers as well as breaking ground loop and reducing noise.

The volume control is basically a high grade Elma 20 position switch which connects different transformer windings via hard wired, silver plated Teflon covered wire. It features 6 inputs, two of which are balanced XLR connectors and the other four are standard phono RCA connectors. Output is via single ended or balanced and there is also the facility to add 6 dB of gain and lift the ground to reduce noise.

The transformers have a wide and flat Frequency Response of 10 Hz - 300kHz within a tolerance of + or - 0.5dB.

So far we have pitted this against a variety of active pre amplifiers that cost several times as much and it has always shown up colourations in the alternatives, whether it be glare from a transistor pre or euphonic bloom from some valve designs. We think this is an absolute bargain bringing unheard levels of transparency to almost every system.

It is available in brushed aluminium or anodised black (as pictured below).

Silvercore Preamp One

To say I’m delighted with the performance of the beautifully German hand made Silvercore Preamp One would be a massive understatement, I have long championed the superiority of transformer volume controls in place of traditional pre amplifiers and the Silvercore has redefined what I thought was possible at anywhere near this price point.

This is a real purist design, it features a pure silver signal path, from the csilver plated onnections through to all the internal wiring - both inside and outside the transformers. There are three phono (RCA) line level inputs and a choice of phono or XLR output. Switching is done by high quality silver plated Elma switches. The dual mono design has twelve volume steps that range from -48dB to 0dB and it works in a logarithmic manner, the lower volume steps are 3dB apart and the higher ranges are 6dB, in use this provides a good range of control - much more than you’d ever expect from a comparative limited number of steps and unlike many other designs I rarely feel that I would like to listen between two of the steps, they're that well spaced. The casework is constructed from polished stainless steel and white Delrin and looks wonderful.

This has all the strengths of a good TVC- great dynamic range and tonal colouring that is natural, where it scores over its competition is the lack of grain to the higher frequencies and removal of muddle and strain when the going gets complicated in the upper midband. It sounds effortless yet never boring and simply ‘gets out of the way’ more effectively than any design close to this price point.

Silvercore Preamp One: £2,500.

Croft Acoustics Micro 25RS

New top of the range Croft pre amplifier. Over the ‘R’ version featured above, the ‘RS’ adds an improved line output stage (which naturally benefits the phono stage which also passes through it), improved components/socketry and HT regulators. It’s split into two of the standard Croft chassis with the power supply separated from the audio stages and to allow sufficient room for all of the components (including the substantially over rated 550va transformer). More details to follow.

Croft Acoustics Micro 25RS pre amplifier: £2,800.

Silvercore Pre 324

The Silvercore pre 324 is their top TVC pre amplifier. Like the simpler Preamp one it is entirely silver wired throughout, including the transformers themselves, with 99.99% pure silver. The 324 features larger transformers and a greater number of steps allowing fine control of the volume in 2dB steps over 24 volume positions. It features 3 inputs (they can be either Balanced XLR, single ended phono or a combination of both) and XLR or single ended phono outputs.

The frame of the enclosure is made from a choice of either Delrin (as used on the Preamp one) or Zebrano wood (as shown here), with top, bottom and rear panels being made of laser cut polished stainless steel.

Silvercore Preamp 324 in Delrin: £4,120

Silvercore Preamp 324 in Zebrano wood: £4,370

Audio Note M3

The M3 uses a choke smoother valve rectified power supply and 5687 valves driving HiB double C-core copper output transformers. It produces an effortless sound with a wonderfully deep and spacious sound stage. Available with silver or black acrylic fascia.

Audio Note M3 Line level pre amplifier: £POA at manufacturers request

Audio Note M3 Phono & Line level pre amplifier : £POA at manufacturers request

Music First Audio TVC Reference: £8,995

Finding a way to better the Music First Audio TVC’s (as detailed above) was never going to be easy - it’s been our reference for several years. So when the new flagship was announced, the Reference, we were a little skeptical as to how much of an improvement they could make.

Let’s deal with the boring bits first - perhaps the greatest criticism leveled at the Music First Audio pre amps have been a direct result of their purist design. The cases whilst being made from aluminium for the best sound quality aren’t especially chunky or obviously styled, they have always been simple but plain, with function over form. The fact that they lack remote control has also caused an issue for some people.

So with the Reference you get a much more luxurious appearance with a wider range of facilities. The case is naturally still aluminium, but is more attractively styled. Hidden inside there has also been greater attention paid the way the components are mounted. The transformers, named the “Nickel Bricks”, have a 25% bigger core than the other models, with refined winding geometry and improved shielding. The +6dB switch has also now been integrated into the main volume control (instead of a switch on the rear), seamlessly working when you need a large amount of gain in an insensitive system. There are also now dual single ended and balanced outputs, perfect for biamped setups. To top it all off it has a remote control and even two tape outputs (with their own separate isolating transformers).

Now to the important and interesting bit, the sound! The first thing you notice is the way it resolves even more information, particularly at the frequency extremes. Starting with the treble, the leading edges are better defined and there’s even more information, yet there’s no hint of brightness, the best description is that it reproduces a very accurate rendition of the energy that you hear when listening to live music, the bite and brilliance is there without it sounding in anyway false or hyped.

The mid band shows greater refinement, almost sounding overly smooth until you realise that the hint of grit and graininess you’re used to is not actually on the recording. The bass is also crisper and able to plumb deeper depths with greater authority yet remains completely effortless throughout.

As you can probably guess we’re very impressed with this preamp, we feel it has redefined what is possible. The price is unapologetically well into high end territory - it has to be as it’s enormously labour intensive to build, with each one taking two weeks just to assemble, but we’ve not come across nothing else, even from much more expensive designs that we’d rather own. MFA have moved the benchmark again...

Please note that the photographs here are of a pre production unit which does not reflect the cosmetic fit and finish of production models, but we wanted to bring you photographs of it as soon as we could.

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