Can you do a revision of my 405 FAQ's

How can I have my 405 making better music than a new one?


I often get e-mails from people asking "Can you do a full revision of my 405 (2)? How much would it cost? What exactly would you do? How much time does it take?" etc...

The answer is: yes, I can. It used to be a hobby but now I'm starting up a company, "DaDa Electronics", specialised in the revision and upgrade of vintage high-end Hifi.

How much would it cost?

One remark first: a big part of a revision is transportation-cost (forth and back). If you are in the US click www.quad405.com. If you are in Europe: keep on reading.

For a complete 405-revision I charge 145 Euro, everything included - except transportation costs.

What exactly is included in a complete revision?

• All electrolytic capacitors (which dry out) are replaced by new ones
• The power-supply capacitors are replaced with BC Components 10000 MF 63 V
• The input-opamp is replaced with Burr Brown OPA604
• The input-circuit is adapted to the new chip (power-supply of +/- 15 Volt, feedback)
• The input-sensitivity is adapted to your pre-amplifier
• The complete internal cabling is replaced with wire with better specs
• The input/output connectors are replaced with high-quality gold-plated connectors, leaving the DIN-input in place, adding parallel RCA-inputs
• Some capacitors are added to improve the quality of the power-rails, some resistances are replaced with metalfilm 1%.
• The amp is measured and calibrated with professional lab-equipment

Do you use high-end audiophile components?

No, I don't. I use good quality standard components. If you want high-end components like Nichicon Black Gate 15000MF for the power-supply this can be discussed. In general the effect of "audiophile components" on the sound-quality will be minimal and the price will be high.

Do you replace the transistors?

It depends. In general transistors don't deteriorate like caps do. If they influence the sound quelity they might be replaced (like the power-transistors might be replaced with 2N3773 if necessary).

What if my 405 is broke?

It depends. If the reason is a bad connection, a broken fuse or a broken transistor, this is included in the revision. If the transformer or another essential component is broke it will have to be replaced at an extra cost.

How long does a revision take?

A full revision takes 2 weeks except if there are unforseen problems.

What are the options?

There are several options (see previous posts on this blog):

• Adding the Velleman K4700 Loudspeaker-protection with power-on delay: 45 Euro
• Replacing the transformer with a 300VA Toroidal transformer: 94 Euro
• Burr Brown OPA 627 or 637 chips instead of OPA 604: 70 Euro
• Changing the 405 to parallel Monoblock 125 Watt: 25 Euro
• Changing the 405 to serial Monoblock 190 Watt: 95 Euro
• Adding a symmetrical 0 Dbm input: 95 Euro
• Having the Chassis professionaly repainted: ask for a quotation

Is there a warrantee?

Yes, there is a 6 month full warranty after the revision. It excludes damage due to transportation or misuse but it includes the complete amplifier, not only the replaced components.


Can you do a revision for other Quad's?

Indeed. I am specialised in revisions for Quads between the 33 and the 606, the vintage B&O receivers and the Revox taperecorder A77.

How to proceed?

Send me an e-mail (verdonckt.stefaan@skynet.be) describing the 405. Adding a picture of the inside and describing the pre-amp and the speakers it is used with is very usefull.

To send it to my address (in Antwerp, Belgium) you could remove the top- bottom- and side-covers to reduce weight and transportation-costs. Make sure it is well-packed.

Stefaan