Classique – Phono Valve Preamp Amplifier With Passive RIAA Using 12AX7 / 12AU7 – DIY Kit

£300.00

Checkout the WHITE PAPER for the Classique – 12AU7 12AX7 Phono Valve Preamp Amplifier With Passive RIAA – DIY Kit.

To All Vinyl Lovers…

This is an all-valve DIY 12AX7 and 12AU7 phono amplifier kit that enables you to use your moving magnet record player with your integrated amplifier.

Similar concept to all designs in our Classique range, this DIY phono amplifier uses traditional design and topology which have been used and tested for many decades. It is powered by two 12AX7 valves for passive RIAA equalization and a single 12AU7 valve as the buffer stage. You will only need one phono PCB per amplifier to power both left and right channel.

And my impression of what we have here is that it’s very good indeed, outstandingly so… – see full review HERE

We designed this DIY phono preamp kit to be in the exact same size as all other kits in the Classique range. The mounting plate, which can be ordered separately, will enable you to setup the kit as we designed it.

It is worth noted that designing a phono amplifier in general is pretty tricky due to its nature. This is mainly caused by the fact that all components have to be setup accurately to make sure that the RIAA equaliziation is done correctly. The components are of very low tolerance value where it matters. Additionally, there is also the challenge of noise (internal and external).

Classique – Phono Valve Preamp Amplifier With Passive RIAA Using 12AX7 / 12AU7 – DIY Kit
Classique – Phono Valve Preamp Amplifier With Passive RIAA Using 12AX7 / 12AU7 – DIY Kit

So, we have made it easier for everyone to setup this DIY phono preamplifier kit. It is designed to use electronic components that are readily available from your usual electronic shops. They are readily available which means it will be easy to maintain your amp.

There are only two PCB’s involved. One for the phono amplifier, and the one for the power supplies.

The power supply PCB is responsible for supplying the high voltage as well as the (DC) low voltage for the heater filaments.

We also included two transformers in this design, one for the high voltage and the other for the low voltage to decouple any noise from each other.

Remember that you will need to purchase the enclosure/mounting plate separately if you wished.

To conclude I believe this should be a permanent keeper for your system , it’s both a stunning execution and interpretation of a classic design and musicality it’s absolutely brilliant

See a testimonial on this preamp HERE.

If you are ordering from outside the United Kingdom, there maybe some custom taxes of duties to be paid to your local custom and duty enforcers. Please make sure that you are aware of this.

In stock

SKU: KIT2 Category: Tags: , , , ,

Description

As mentioned before, this is a kit where you will get the parts and components (electronics, connectors, transformers etc) and you will have to assemble them yourself.

Once you have completed the build, the phono valve preamp amplifier is intended to be used together with your vinyl record player. You will still need to have an integrated amplifier in your system. The phono valve preamp amplifier will amplify the output from your moving magnet cartridge on the record player, to be large enough to be fed into your integrated amplifier. It sits in between the record player and the integrated amplifier.

Features/Specifications

  • Common cathode class-A gain stage with no feedback, passive RIAA equalization and cathode follower buffer stage
  • 2 x 12AX7 for RIAA correction and 1 x 12AU7 for buffer stage
  • Cartridge Compatibility: Moving Magnet
  • Input Impedance: 47k ohms (set by input resistor – can be changed accordingly)
  • Output Impedance: 322 ohms
  • Gain: 39 dB gain @ 1kHz
  • Distortion: <0.05% @1kHz
  • Equalization: RIAA +/- 0.5 dB, 40Hz to 30kHz (measured)
  • Regulated 12VDC heater power supply elevated to 90V. Ripple voltage of 0.0017v rms at 450mA
  • Current draw: 24mAmp at 300VDC
  • Classic Dale grid resistor
  • Reverse-able main Phono amp PCB. Components can be soldered on the same side as the valves OR on the opposite of the valves. This feature enables builder to mount the board with valves outside chassis OR valves being inside of the chassis
  • Locally designed and made power transformers
User build - Classique Phono Valve Preamp Amplifier With Passive RIAA Using 12AX7 / 12AU7 – DIY Kit
User build – Classique Phono Valve Preamp Amplifier With Passive RIAA Using 12AX7 / 12AU7 – DIY Kit

How Does It Sound?

We have only had positive feedbacks on the sound produced by this valve phono preamp kit.

Listeners have been using variety of words to describe the sound. However, the most consistent one that we always hear is that “it is more pleasing – less harsh compared to my current system”. The audio amplification with valve, with some even-order harmonic distortion, creates that warm and rich sound that a solid state amplification might lack.

Listeners have also been comparing the preamp to a number of other “audiophile” phono preamp that you can find in the market.

If you have any question about this, please get in touch.

“One of the best purchases I’ve made …”

See testimonials HERE.

Documentations / Downloads

The Components

The list below is the complete list for the kit.

  • 2 x power transformers with flux bands – locally made by primarywindings.com
  • 1 x integrated power supply PCB and components (for B+ and heater filament)
  • 1 x phono amplifier PCB and components (only one piece is needed for stereo channel)
  • All screws / nuts / bolts / spacers
  • Double pole single toggle power switch
  • RCA input/output terminals
  • IEC power socket with with internal fuse slot

The Kit

You will get the following:

  • Phono PCB and all electronic components
  • Power supply PCB and all electronic components
  • 2 power transformers
  • connector and sockets
  • power switch

NOTE: You will have to add/purchase the following items separately:

  • 2 x 12AX7 and 1 x 12AU7 valves
  • Enclosure (checkout our enclosures here)
  • Aluminium plate compatible with all our enclosures
  • fuse
  • IEC cable and plug (a.k.a kettle plug)

Don’t forget to checkout the WHITE PAPER for the Classique – 12AU7 12AX7 Phono Valve Preamp Amplifier With Passive RIAA – DIY Kit.

The Enclosure

An optional enclosure can be purchased to be part of this kit. You can see what the options are here. We highly encourage you to purchase an enclosure as it compatible with the dedicated mounting plate. The mounting plate will not only make assembling the kit pretty straight forward, it also enables you to use the default positioning of the components and parts as mentioned in the build manual.

Enclosure DIY?

We also supply the drawings of the enclosure if are thinking about making one yourself. Check it out here.

User build - Classique Phono Valve Preamp Amplifier With Passive RIAA Using 12AX7 / 12AU7 – DIY Kit
User build – Classique Phono Valve Preamp Amplifier With Passive RIAA Using 12AX7 / 12AU7 – DIY Kit

Audio Analysis

Graph below shows the measured frequency response tested using 2 x Electro Harmonix 12AX7 and 1 x Electro Harmonix 12AU7:

Measured frequency response of the RIAA correction.
Measured frequency response of the RIAA correction.

The Setup

Once you have completed the kit, the Classique Phono Valve Preamp Amplifier will be sitting in between your record player (with moving magnet cartridge) and an integrated amplifier. Its job is to amplify the audio signal from your record player to a level that can be used by an integrated amplifier (e.g. the Classique 6BM8/ECL82 SE Integrated Valve Amplifier).

The audio setup showing where the Classique Phono Preamp would be. It is placed in between a Moving Magnet Record player and an integrated amplifier.

Completing the Build

In order to build this kit, you will need to have the correct tools and devices. We have created a list of items that you might help you during the build together with the links to where you can get it from.

Remember that the list is only a recommendation. We all have our own preferences with what and how to use things. Have a look at the list HERE.

IMPORTANT NOTES AND DISCLAIMER

This product is sold as a kit, which means that buyer would have to assemble all parts. Printed circuit boards (PCB) are not populated so all parts will have to be soldered onto the PCBs.

It is assumed that buyers would have the knowledge of:

  • soldering
  • assembling screws/nuts/bolts
  • highly skilled and knowledge of high voltage electric circuits and parts
CALEDONIAN AUDIO will take no responsibility on any injury or death as a result of the work conducted to assemble this kit. Please make sure that you know what you are buying and handling. If you have never done any electric and electronic work before we would strongly suggest that you consult us before buying this kit.

Additional information

Weight 3 kg
Dimensions 30 × 30 × 10 cm
Classique Phono Options

KIT A, KIT B, KIT C

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