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Col's Vintage Hi Fi Restorations, Wynnum West, Brisbane (2026)

07/10/2024

FOR SALE: $800

This AU-4900 from 1975 has been completely overhauled to an extent that few take the time to do. It has the highest output of its stablemates, the AU-2900 and AU-3900, emitting 35W per channel into 8 Ohms.

After 50 years, these amps have a lot of issues if they’re working at all, so to enjoy them at their best and avoid ongoing issues, it’s a good idea to sort out the known problems and do all the proactive maintenance. Almost without exception, amps from this era have not been properly or regularly serviced and are often on their last legs. What seems like a bargain can turn sour if an amp needs ongoing repairs to keep it going, especially at repair shop rates of $100/hr and up.

I prefer to do it once and do it properly, addressing key areas of usual failure and keeping within the bounds of fiscal sanity.

Apart from the usual general clean and detail, service, re-lube, and removing corrosive capacitor glue, all electrolytic capacitors have been replaced with high quality caps, mainly Nichicon Fine Gold and KG for filters. Poly caps were used in place of some smaller value electrolytics.

Main output transistors were replaced with more robust On-Semi T03 type. Not usually needed, but gain was down in the originals and cases corroded, so it was time for an upgrade.

Small signal transistors on tone/filter and main boards replaced with new (gain matched where needed).

Fusible resistors replaced. (It’s mainly the fusible resistors and failing transistors that kill these amps over time).

Most diodes including all power supply diodes and other germanium and Zener type were replaced.

All circuit boards were re-soldered and cleaned of excess flux to better than original condition.

Case professionally powder-coated in black.

New Bourns type bias trimmers installed for better bias/cente voltage stability and safeguard against DC spikes from unreliable original trimmers.

It’s now in tip top working condition.
There is around $210 in parts in this and 15 hours labour.

Demo available at Wynnum, Brisbane.
(Sorry, will not post unless I already know and trust you)

22/09/2024

SOLD. A whole lot of value for $350. This stylish Yamaha R-300 receiver from early 80s (made from 80-84) features one of the coolest looking LED tuning indicator systems I’ve encountered and was a flash new feature at the time. But the thing I like most is the sound signature of these receivers. They just got it right to my ears. It now needs an appreciative home where it will get the use and appreciation it deserves.

Like most of the gear in my collection, this receiver has been completely serviced and overhauled including replacement of electrolytic capacitors on tuning board and the preamp/amplifier boards, which were treated to Nichicon Fine Gold, high quality audio capacitors.

The tuner has also been recalibrated and FM sounds great on this.
Puts out a healthy 30-35 Watts per channel into 8 Ohms and frequency response is 10Hz to 100kHz.
Pick up/Demo Wynnum, Brisbane.

19/09/2024

Another Sansui AU-555A brought back to life. These amps have a cult following among audio enthusiasts and were made between 1969 to 1974.

This one was given a total overhaul including the renowned Leestereo mods described in the Audiokarma forum, regarded by many as the go-to guide for improving performance in these amps.
I would not own one of these amps without implementing these changes as they bring noticeable improvements in low and high frequency definition, power transient handling, and bring the phono/EQ board in line with later model Sansui’s. https://audiokarma.org/forums/index.php?threads/leestereos-restoration-upgrade-of-a-sansui-au-555a.816754/

These amps are now 50 years old and need a thorough overhaul to bring them back to full potential, but the time and effort is worth it in audio bliss. Electrolytic capacitors deteriorate and there are a significant number of problem transistors in the 555A that need to be replaced before they cause serious issues.

A word of warning. Anyone buying one in original condition should factor this potential work into their purchase. I have overhauled many vintage amps bought for top dollar from sellers preying on buyer ignorance. Unfortunately, many sellers seem to think their unrestored items are worth as much as one that has been fully overhauled.

To bring the 555A back to premium condition, there is around $200 in parts and around 15 hours’ labour. At standard repair shop rates of $100/hr and up, this can make for a very expensive restoration. If I was paying those rates, my vintage hi-fi obsession would be snubbed out very quickly. No wonder a lot of these amps are lost forever as the expense is hard to justify for many and proper restorations vs ad hoc repairs are left in the hands of a few ardent (crazy?) enthusiasts like myself.

If you do buy one of these in original condition, be wary of previous work done by lazy or careless techs or the sausage-fingered enthusiast who thought they’d have a go, damaging circuit board tracks and installing poor quality parts. I’ve lost count of the number of amps where I’ve had to remediate damage and shoddy work, in some cases by so called professionals who should know better or who fail to admit their limitations. Be very wary of taking vintage audio gear to a repairer who is not familiar with vintage audio devices, unless they have endorsements for performing similar work to a high standard. These amps are things of beauty and deserve to be preserved and treated with care and respect. Rock on!

22/04/2024

Here’s a Sansui AU-117ii overhaul I completed recently. It was beyond reasonable repair and filthy but I decided to rescue it to use as a test amp.
This is the entry model for the 17 series and has a low profile case. This Mkii version has higher output than the original 117. The 117 is 15WPC and the 117mkii 25WPC.
It had the usual age-related problems for the 17 series.
All the fusible resistors had gone open or high. Outputs on one channel were blown so I replaced all the outputs with more robust subs, TIP42’s.
Electrolytic caps were replaced with good quality Nichicon caps. The orange Elna low leakage caps were left as-is.
I replaced all transistors on the pre/driver and phono boards. Many are known to go noisy or fail including the double 2SA798’s.
All joints were re-soldered as preventative maintenance and as the existing ones were very dry (Fair enough after 40 years plus and bad storage conditions).
Zener diode and rectifier diodes also replaced.
It took a weekend but I’m glad it has a new lease of life.

01/12/2023

NOT AVAILABLE FOR SALE. This Sansui AU-101 has had a full overhaul and upgrade with quality audio caps including Nichicon Fine Gold, Muse, KG and Kemet poly caps.
Power supply caps increased in value and rectifier diodes upgraded.
All transistors on tone-board replaced with gain-matched low noise equivalents.
Speaker terminals replaced with easier to use banana-plug type.
Cosmetically excellent apart from a couple of bits of veneer missing from front of side panels.

01/10/2023

Another AU-417 amp rescued. This one was not working and in crusty condition – dry boards, dirt, corrosion. Sorted out the usual age-related issues and those common to the 17 series in general.
Electrolytic capacitors replaced with mainly Elna Silmic II and Nichicon FG or UES bipolar series. Fusible resistors had failed so replaced along with VD1212 diodes. Most small transistors were replaced as many are prone to cause problems. All boards re-soldered.
Corrosive capacitor glue was removed from circuit boards.
So after the overhaul the amp was working perfectly but had a weird fault. Only worked on 1 input but this worked no matter which position the switch was on.
After a bit of troubleshooting, it turned out to be a broken plastic gear inside the selector switch so the switch was stuck in one position. No way of replacing the switch assembly so best hope was to attempt repair. This was done by carefully dismantling the switch and thankfully the gear cog was able to be turned over and used on the side with no broken teeth. Working perfectly again now but a painstaking job and I forgot to get pics of the inside of the switch! This 417 should kick on for a while yet.

30/07/2023

Another project finished. This Sansui AU-5500 from 1975 had the usual age-related issues of this series. Replaced electrolytic capacitors with mainly Nichicon FG and UKL. Replaced most transistors as some were looking heat stressed and they are prone to going noisy. This series of amps are like a Meccano set to assemble, reassemble so it is always best to check and re-check your work before putting these back together to avoid another disassembly. Now onto the next project, a Sansui AU-777A that is low in one channel

02/07/2023

This Luxman L-80V needed a total overhaul after sitting in a box in pieces for a few years in a sorry state. It had quite a few blown transistors. I won’t go into details as I suspect no one really reads it, but suffice to say, it needed a fair investment in time and parts and the end result was well worth it. These are one of my favourite Luxmans in terms of aesthetics, build and sound. I have 2 of these L-80V’s and will start on the other one soon. This one will be for sale in a few weeks.

26/06/2023

This stunning NAD 90 amplifier from 1976 emits a respectable 55 Watts into 8 Ohms (actually higher). The amp has been overhauled and serviced including replacement of most electro capacitors with audio grade caps (mostly Nichicon FG, KA). Original Sony outputs tested and new thermal washers installed. Inputs, controls cleaned with Deoxit. DC offset and bias voltages re-adjusted. Some transistors, resistors and meter lamps also replaced.

18/06/2023

This Sansui AU-555A was given a comprehensive overhaul including all improvement mods from Leestereo (Audiokarma) using high quality parts. The amp has sprung to life again better than ever and taken to the next level. This one will be for sale soon after I have enjoyed it a bit more.

02/05/2023

Another Sansui revived. This 1969 Sansui AU-222 had electrolytic capacitors replaced with audio caps including Nichicon KG Gold Tune, Nichicon Fine Gold, Nichicon UKL low leakage, Elna Silmic II. TO92 transistors were replaced on control board, phono and main boards. Oil type spark suppression cap replaced with poly cap (this reduced the start up pop greatly). This little amp seems surprisingly powerful for it’s 18W output and has great sounding phono, which I suspect is helped by the original mica caps, which also appear on tone and main amp boards.

21/02/2023

This Sansui AU-417 from late 70s limped in one day with the usual issues common to this series of amps. It was barely coming out of protection and when it did, sounded like fireworks popping off. All boards needed a proper overhaul.
This included replacing electrolytic capacitors (except main filter caps – these tested perfectly). Most of the other caps removed were now out of spec. Suggest using good quality audio caps as these make an appreciable difference in sound quality in an amp like this.
Other problem parts were replaced including most TO92 transistors (many in this amp are known to go noisy), varistors and fusible resistors. Most of the fusible resistors measured up to 3 times their face value, so it was surprising the amp came out of protection at all.
All boards were also re-soldered as the old joints were pretty dry and there was some rust remediation needed on chassis and baseplate. On main output transistors, the thermal washers and messy heatsink paste was removed and replaced with modern silpads (no paste required).
Sansui amps from this era are starting to show their age now and more and more are failing or experiencing problems due to aging components. If yours has not been checked or serviced since new, it would be wise to get it overhauled and properly serviced as they really are running on a wing and a prayer now. Remember, these things are over 40 years old now.

Col's Vintage Hi Fi Restorations

07/10/2024

22/09/2024

19/09/2024

22/04/2024

01/12/2023

01/10/2023

30/07/2023

02/07/2023

26/06/2023

18/06/2023

02/05/2023

21/02/2023

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