Cambridge Audio CXN V2 Tube Modification

Introductory Pricing (Modification Only)
$1500 (customer supplies the Cambridge CXN) + shipping to the customer fully insured.

What tubes are used in the modification and do you recommend any upgraded tubes?
Stock Tubes Supplied: New Production JJ 6DJ8/6922
Compatible Tube Variations Include: 6922, 6DJ8, 7DJ8, 7308, ECC88
Recommended Tube Upgrades: Telefunkens, Amperex, Siemens

What is included in the tube modified upgraded?
1. Replacement of stock DAC power supply with our own design.
2. Replacement of the entire stock SS analog stage with our own all-tube based analog stage and its own power supply.
3. Fully balanced in to out, with both RCA and XLR outs.
4. The entire mod is enclosed in one box, no outboard supply or umbilical.

First of all, we make sure that all audio circuits are powered by our own supplies. The stock unit uses a switched mode power supply (SMPS). These are noisy and don’t produce the best quality power and hence not the best sound. A linear supply, based on a power transformer is more costly for the manufacturer and can generate a lot of heat, depending on the power draw for the various processors and chips on the board. We leave the SMPS to power the computer chips, but not the DAC. We bypass the stock analog stage, so there is no impact on the signal path there from the SMPS either. Our mod PCB includes the high and low voltage power supplies for our tube circuit and the DAC stage. In addition to the PCB, we install our own power transformer, high voltage choke and a pair of Swedish Lundahl gapped output transformers for the tube stage. Thankfully there is room inside the unit to fit all of this iron and new circuitry.

Secondly, we replace all op-amps (inherently feedback based cap coupled at the outputs) with a fully balanced, transformer coupled, class A tube preamp circuit, based on our $10K Reference LS 300 preamp. The stock analog stage is SS, specifically op-amp based. It is well designed and based on a differential output with dual Wolfson DACs. The opamps are cheap, sound OK and are powered by a SMPS. Having said all of that, the stock unit sounds good! This is always what I look for in an ideal product to modify.

This Signal Path = DAC – analog filters – 6922 tube – Lundahl gapped output transformer – RCA/XLR connectors. No capacitors in the signal path! This all translates to a low noise floor, fantastic resolution, huge soundstage and the liquid and organic musicality that can only be produced by a Class A tube circuit. Add to that, the technology and flexibility of this unit at $1K retail and it is fantastic!

Initial Listening Impressions per Daniel Wright
The stock Cambridge Audio CXN is a good sounding unit. If it has any shortcomings, it is the lack of body, naturalness of sound and a constricted soundstage. This is due to inadequate power supply design and the use of feedback based operational amplifiers in the SS analog stage.

We address this with our own power supply design for the tube circuit as well as a separate regulated supply (5VDC) for the DAC.

When comparing the modified unit to stock, level matched, A/B, I hear first of all a bigger soundstage and a fuller midrange. As I listen more closely and compare the two, I realize that there is a weight and body to the sound that is not present with the stock unit. The noise floor is black and resolution is exceptional. The tubes add a liquidity and 3-D quality that is not present in the stock unit.

I find that tubes for the purposes of amplifying voltage, such as this application, simply do less harm to the signal path. There are no capacitors or transistors in the signal path, so it is simply clean and elegant. The use of Lundahl output transformers insures complete galvanic isolation between the player and connected equipment. This means less noise, edge and glare and a much blacker background.

In a word, I would describe the sound of the modified unit as Organic!

Tube Modification Voltages
Available in 120v.

How tall do the tubes sit above the chassis?
Cambridge Audio CXN V2 Stock Height = 3.4”
Tube Height Above Cambridge Cover = 1.3”
Total Heighth of Stock Player + Tubes = 4.7”
Recommended Rack Clearance: 5.5” minimum, 6” recommended

Available Connections:
USB, Coaxial and TOSLINK wired connections.
Apple AirPlay 2 and Google Chromecast built-in wireless connections.
Roon Ready. (Requires a Roon subscription.)
Spotify Connect, TIDAL and Qobuz built in.
High-Quality Internet Radio Streaming.
StreamMagic app for iOS and Android.

Available Audio Formats:
ALAC, WAV, FLAC, AIFF, DSD (x64), WMA, MP3, AAC, HE AAC, AAC+, OGG Vorbis

Stock Digital Filter:
2nd Generation ATF2 up-sampling to 24-bit/384khz

What kind of warranty is provided?
ModWright agrees to warranty the Cambridge Audio CXN V2 Tube Modification for a period of 3 years. Warranty is non-transferable to second party. For more details, see downloads in the right column.

What happens if there is a stock component failure or damage that occurs to the unit, outside of the modification?
ModWright Instruments, Inc. becomes the service center for your unit indefinitely, post modification. If there is any kind of stock component failure, the product would have to be returned to ModWright at the customer’s expense and we will communicate with Cambridge Audio on your behalf to resolve any unforeseen stock component failures. The customer is responsible for all parts cost and labor associated with a stock component failure. This type of repair is not covered under the ModWright warranty.

How do customers place an order?
Customer must supply the player and may have it drop-shipped to our address from retailer. A billing and shipping address with a phone number and email address must be provided to generate the work order. Once this is complete an invoice will be sent to the customer for review. If everything looks correct, a 50% non-refundable deposit required to secure a firm start date. Work will be completed in no more than two weeks from start date. Remainder due, including shipping cost, upon completion of work. Customers do have the option to pay up front in full if they desire.

What forms of payments does ModWright take?
For US customers, we can take Visa, Master Card, American Express & Discover. For international orders, we require a bank wire transfer. We do not provide personal financing through ModWright Instruments, Inc. but if you have financing through PayPal, we are more than happy to send you an invoice through PayPal so you can pay with their credit option.

Where do customers ship their unit for modification?
If you have purchased your Cambridge Audio CXN V2 and you are planning to send it in for modification OR you are ordering it new from a retailer and planning to have it sent direct to us, please ship it to the following address:

ModWright Instruments, Inc.
Attn: YOUR NAME
21919 NE 399th Street
Amboy, WA 98601
USA

In regards to return shipping, if you need a quote, I will need your shipping address and a contact number. We primarily ship through UPS but we have a FedEx account as well. If you would like to use your own personal shipping account, we can coordinate that as long as we have the account number. All Cambridge Audio CXN V2s are boxed in their own packaging prior to shipping back to you.