Quad Kits 1 & 2 are now made up and in stock for immediate despatch.
Quad 405 Restoration & Upgrade Kits - Now heavily revised and even better value for money
The vintage Quad 405 is still a great sounding amplifier, combining the very best of Quads' legendary design skills and build quality. As with all old hi-fi though, the capacitors inside the Quad 405 will be getting pretty long in the tooth. Electrolytic capacitors really only have a lifespan of around ten - fifteen years, after which the electrolyte dries out, the esr goes up, and the all important sound quality goes down. This degredation in sound quality is so slow and steady, that the owner may not notice the change until it reaches a critical level. Simply replacing the electrolytic capacitors will rejuvenate your Quad 405. In fact, using todays high-quality components, your Quad 405 should sound better than it did when it left the factory, and more than capable of showing many modern amplifiers a thing or two!
Here at Diy Hi-Fi, we are firm believers in component quality. Yes you can fit standard parts, and yes your amp will sound good, back to its old self, but why not use modern, Audio-Grade components which are made for the job in hand? We have spent many hours evaluating and selecting the finest sounding parts, and feel we now provide best cost/performance ratio for each kit. Using Audio-Grade components will allow the Quad 405 to sound better than ever, with increased levels of detail, lower levels of noise whilst still retaining the classic 405 character.
Quad 405 mk1 & mk2 Upgrade Kit 1
2 x F&T Cap Low-ESR/ESL power supply smoothing capacitors - C14, C15
2 x Audio-Grade 47uF Panasonic Bi-Polar - C2
2 x 100uF 16v Rubycon ZA - C5
2 x 47uF 63v Elna Silmic - C10
4 x 47uF Nichicon PS (405-2) - C18, C19
2 x 10uF 63v Bi-Polar (Quad 405-1 Output Protection Board) - C17
2 x LME4910NA National Semi Opamps & Sockets
2 x Capacitor Clips
Price: £30.00
Optional: Upgrade opamps to LME49710HA "Tin Hat" TO-99 types for even beter sound - see bottom of page
Fitting Service Price: £60.00 Includes fitting, testing and insured return UK postage
Quad 405 Modification Kit 2
Through the use of even better quality components, and replacing key capacitors in the signal path, our Kit 2 offers a marked step up in quality over the Kit 1. The input stage gain is also reduced for lower distortion, all resulting in greatly improved detail and dynamic ability.
2 x 10,000uF 63v F&T Cap Low-ESR/ESL power supply smoothing capacitors - C14, C15
2 x 33uF 25v Rubycon ZA - C2
2 x 100uF 16v Rubycon ZA - C5
2 x 100uF 63v Panasonic FC - C10
4 x 47uF 63v Panasonic FC (405-2) - C18, C19
2 x 10uF 63v Bi-Polar (Quad 405-1 Output Protection Board) - C17
2 x 680nF Wima MKS2 - C4
2 x 4k7 1% Resistor - R4
2 x 22k 1% Resistor - R6
2 x 120pF 1% Silver Mica - C8
6 x 330pF Wima MKP - C7 (mk1-C9, C11)
2 x 9A Inductor - L2
2 x LME4910NA National Semi Opamps & Sockets
2 x 100uF 16v Rubycon ZA Opamp Decoupling Capacitors
2 x Capacitor Clips
Price: £55.00
Optional: Upgrade opamps to LME49710HA "Tin Hat" TO-99 types for even beter sound - see bottom of page
Optional: Upgrade output protection circuit to Velleman K4700 Relay Protection Kit - see bottom of page
Fitting Service Price: £115.00 Includes fitting, testing and insured return UK postage
Quad 405 Modification Kit 3 Coming Soon...
The Ultimate Quad405 upgrade including: Burson Discrete Opamps**
Our Kit 3 builds on the Kit2, essentially replacing the "crowbar" speaker protection circuit with the Velleman kit and it's high quality relays. This interferes far less with the purity of the audio signal. The startup delay and instant disconnection of the speakers from the amp circuit on shut down also allow the use of the amazing Burson Audio Discrete Opamps without the horrid switch-off thump (see bottom of page). Fitting these incredible modules in place of any IC opamp moves the Quad405 into new territory in terms of sound-quality. Detail levels improve, separation improves and the noise floor drops away even further. Dripping with realism and tonality, instruments appear out of an inky black background whilst sacrificing none of the original sound character. We are totally blown away by the improvements.
Expect to hear far more detail, more realistic tonal information and a lower noise floor with improved speed and dynamic ability. Currently available only for the 405 mk1, mk2 version coming soon.
2 x 10,000uF 63v F&T Cap Low-ESR/ESL power supply smoothing capacitors - C14, C15
2 x 33uF 25v Rubycon ZA - C2
2 x 100uF 16v Rubycon ZA - C5
2 x 100uF 63v Panasonic FC - C10
4 x 47uF 63v Panasonic FC (405-2) - C18, C19
2 x 10uF 63v Bi-Polar (Quad 405-1 Output Protection Board) - C17
2 x 680nF Wima MKS2 - C1
2 x 150nF Wima MKS2 - C4
2 x 100k Resistor - R6
2 x 120pF 1% Silver Mica - C8
6 x 330pF Wima MKP - C7 (mk1-C9, C11)
2 x 9A Inductor - L2
2 x Capacitor Clips
2 x Burson Audio Discrete Opamps
2 x 100uF 16v Rubycon ZA Burson Decoupling Capacitors
1 x Velleman K4700 Speaker Protection Kit
Instruction sheet
Price: £TBA
**We only recommend using the Burson opamps when using a Velleman Speaker Protection Kit due to the rather unpleasant thump at switch-off caused by inbalance in the opamps' supply voltages. However, there is an easy fix to this problem described in the very informative and comprehensive upgrade paper by Bernd Ludwig.
Components & Accessories
MJ15003 On-Semi Output Transistors - Price: £4.00 each
LME49710NA - Price: £2.49 each
LME49710HA TO99 "Tin Hat" - Price: £12.00 each
3uH 9A Inductor - Price: £2.20 each
Velleman Output Protection Kit - Price: £25.00 each
Binding Post BLACK - Price: £2.50 each - Fits perfectly into original holes, output protection board will need re-drilling
Binding Post RED - Price: £2.50 each - Fits perfectly into original holes, output protection board will need re-drilling
Quad 405-2 For Sale
FOR SALE - A fully serviced and modified Quad 405 MKII. This amp has been upgraded with our Quad 405 Kit 2 and quite simply, it sounds incredible. Dynamics and soundstage, detail and separation are massively improved, you can hear the fine details and tonality of the instruments, all presented in that typical non-sterile, full-bodied way that only a good 405 can do.
Price: £299
