joel
Painter of Dragons, Maker of Mirrors
I'd forgotten about them. They really do take the P*ss on pricing, but illustrate that there is a serious market for this.
60's & 70's amplifiers
- Thread starter Patcam
- Start date
This thread makes me want to finish my Pioneer SA-9100 off. One channel won't adjust bias properly and the other has variable dc on the output that is fine with no signal but seems to track the music signal. I have carried out the capacitor and transistor replacement as per recommendations on Audiokarma. It just needs a bit more work and it should be done
Tony L
Administrator
None of this comes as a huge surprise to me and I'm sure there will be a very healthy emerging market for those able and willing to service these vintage classics well. One needs to remember that the better Japanese stuff was superbly built and very far from cheap. Modern equivalents e.g. Accuphase, Luxman etc more than illustrate the pricing and market position, so £350 to fully service a Yamaha 2020 or whatever doesn't sound unrealistic as long as it is for a full recap, i.e. makes the item usable for another 20 years or whatever. I'd love to try a fully refurbished 70s Japanese high-end amp one day, something like a Pioneer 9800 or one of the top-end Sony V-Fet jobs.
Arkless Electronics
Trade: Amp design and repairs.
I'll have to keep an eye on the market and maybe reconsider my recent announcement on the matter if there seems enough interest
I just can't see people being willing to pay £350+ to refurbish an amp they won on ebay for £70..... especially as they would probably get say £200 for it if they re-sold it....
I well remember the dark ages of flat earthism when 8 year old range topping Japanese amps were going for £30!
Tony L
Administrator
You could have filled a shed with cheap 301s, LS3/5As, Tannoys etc too... Thankfully we now live in rather more enlightened times now those making audio no longer own the mass media. The internet and forums such as this one have changed the game entirely.
Arkless Electronics
Trade: Amp design and repairs.
Yep. I paid £20 for my first Leak Stereo 20 around 1984!
joel
Painter of Dragons, Maker of Mirrors
Many a container was filled with cheap Garrards, Tannoys and much else besides, and then shipped to Japan.
Times certainly are more enlightened and a lot more fun!
But they were there for people to buy, so why didn't the non-flat earthers here clean up? I ask because I got a Moog Rogue synth for £10 and Tiesco 60 for £20 in about 1987 from the record and rip off in Notting Hill. Just before the Acid House fuelled analogue renaissance. Not because I knew it was coming but because I liked the synths.
linnfomaniac83
I bet you can’t wheelie a unicycle!
Wow, I paid a lot more than that for one, it cost around £180 for it needing restoration, I spent about the same again getting it right, then a baby came along and the amp went. I got my money back but they are fetching crazy prices now. Sounded lovely with my ELAs though!
Robert
Tapehead
Listening to my 9800 as I type.
Fabulous thing - its phono section is actually quieter than many line stages for noise!!
If you said to someone 'build a phono circuit and don't worry about the cost' whats inside a 9800 is roughly where you'd be.
I generally agree with Jez on rebuild costs though. At the moment it's OTT for most people to have something completely rebuilt as the rebuild cost is usually far higher than the purchase price.
However, I'm planning on publishing an article soon on the performance of old capacitors and it makes interesting reading. I have quite literally a bucket load of old caps pulled from kit going back to the mid 70s. Amazingly <1% actually test bad, <5% 'ok' and the remainder absolutely fine with many performing to modern standards.
I've been coming the the view in recent months that wholesale cap replacement is unnecessary, costly and sometimes even harmful.
istari_knight
pfm Member
Humm ... interesting observation Robert. I have often wondered about this myself. Being the owner of several pieces of vintage HiFi it would cost me a fortune and a ridiculous amount of time to do a whole sale Re-Cap on all the electrolytic caps in all of my equipment. Like you I also feel that the risk of damage to the PC board tracks and surrounding components is a risk that needs to be considered before simply ripping out and replacing components.
There are some components that are obviously suspect such as bulging or leaking electrolytic caps or the ROE capacitors in the phenolic resin casings but only if they show signs of cracking or leaking.
It has been explained to me that the best way to preserve or maintain the electrolytic layer in a Capacitor is use it occasionally. I try to make sure most of my vintage equipment gets powered up and soaked for a couple of hours every 6 months or so.
As a side note and a little bit of trivia I had to update some MSDSs at work the other day, did you know that Phenolic resin contain Formaldehyde. So dont eat, inhale or poke any ROE caps into you eyes. But if you do at least I now have the MSDS's that outline the appropriate first aid treatment safe storage details and how to deal with it if it should catch on fire.
LPSpinner.
Tony L
Administrator
I can understand the first two points, but not the last - why would it be harmful to refresh electrolytics like for like?
PS I'm absolutely convinced it is worthwhile in old loudspeakers as I've heard the before and after several times now. I was never entirely convinced with Naim recapping and often felt it took a fair while to relax back to how I liked it, and other than that I've no real opinion - my Quad stuff has been more than a recap in most cases, though I'm in no doubt that the 34/306 you did and my 303 are improved, but neither are entirely like for like (especially my Dada 303). I've got a 405/2 that hums so I assume is in dire need of a recap... and as for my Leak Stero 20, well that was in a right state (a job in progress at present)!
flatpopely
Prog Rock/Moderator
Well having 'come into the light' I just replaced caps that were suffering in my JVC and they made a big difference and left the rest alone. They must be fine as it sounds superb. Just listening to 'Brave' by Marillion on Tidal via the optical digital input and it just does everything so right.
Robert
Tapehead
Will post more tonight, but the function of the capacitor is key when considering replacement. So in a crossover where precise values are setting filter frequencies, yes it's good practice to swap them out. However in amplifiers the jobs performed by capacitors is varied and drift in certain parameters doesn't always impact performance.
My warning over dangers relates to damage done to old pcbs where tracks are fragile, plus is physically complex units the disruption and stress on wiring.
Yes, this has been my personal experience. Despite having a good clean iron and more than a few years of experience, heating up old and fragile PCBs can easily cause the copper tracks to come away from the board. While this can usually be fixed or covered over, it makes any further work on that area of the PCB very difficult.
Also the insulation on some wires can become brittle and quite fragile over 20 plus years, moving or bending it too much can easily cause the insulation to break or crack.
Sometimes you will need to replace an aging component but these days I only do it if the component has failed or showing physical signs of distress. I no longer do wholesale replacements of parts just because they are old.
LPSpinner.
Robert
Tapehead
Just to pick up on the points above, here are a few examples to consider.
- Your 'speaker system feeds the tweeter via a 3.3uf electrolytic capacitor and the crossover point is at 3kHz. After 30 years the capacitor ESR has increased from 0.5R to 1R and the capacitance now measures 6mfd. In the context of the 8 Ohm tweeter the ESR rise has little effect but the capacitance drift will have moved the crossover point down closer to 1kHz.
Clearly this should be replaced.
- Your amplifier uses an input coupling capacitor rated at 47uf in order to block incoming DC. This feeds an operational amplifier with input impedance at 100k Ohms. Measurement indicates that you need no more than 1uf to give a ruler flat response down to <5Hz. Your 30 year old coupling cap now measures 10uf and its ESR has tripled from the original 0.2 Ohms to 0.6 Ohms. The drift in values makes absolutely no difference to performance, and replacing this capacitor would be pointless. In many amplifiers the coupling and input caps are chosen purely because they are 'large enough' with ample margin and because the manufacturer saves money buying a crate of common values.
- Your valve power amplifier uses valve rectification and employs a cap/choke/cap in the smoothing circuit. These caps are typically around 47-100uf at 450-600v. The first capacitor is having to deal with considerable ripple current close to its limits, while the second receives the filtered signal after the choke. Not only is the first capacitor running near its limits but its running next to a searingly hot rectifier. it will be completely farked in <5 years. Clearly these caps need regular replacement because low ESR is essential for low noise.
- The chip based regulator in your pre amplifier is using a small 10uf electrolytic capacitor on its output to ensure stability. Ripple is low, heat is low, and it runs well within voltage rating. ESR needs to be moderate - too low and the circuit becomes unstable - and therefore even a tripling of the original value ESR has no effect. The capacitance value isn't critical within +/- 50% limits.
If these look fine, and the circuit is quiet - it can clearly be left alone.
Actually using a modern high performance low ESR cap in this situation will often give worse performance.
Just some examples of why wholesale ripping out of electrolytics is unwise IME.
Not a view I've always held but one developed after spending a good few years ripping things to pieces and testing them
Over the weekend I'll post some actual test results for 30+year old caps. The results will surprise many - they certainly surprised me.
PS: Agree entirely with LPSpinner.
- Your 'speaker system feeds the tweeter via a 3.3uf electrolytic capacitor and the crossover point is at 3kHz. After 30 years the capacitor ESR has increased from 0.5R to 1R and the capacitance now measures 6mfd. In the context of the 8 Ohm tweeter the ESR rise has little effect but the capacitance drift will have moved the crossover point down closer to 1kHz.
Clearly this should be replaced.
- Your amplifier uses an input coupling capacitor rated at 47uf in order to block incoming DC. This feeds an operational amplifier with input impedance at 100k Ohms. Measurement indicates that you need no more than 1uf to give a ruler flat response down to <5Hz. Your 30 year old coupling cap now measures 10uf and its ESR has tripled from the original 0.2 Ohms to 0.6 Ohms. The drift in values makes absolutely no difference to performance, and replacing this capacitor would be pointless. In many amplifiers the coupling and input caps are chosen purely because they are 'large enough' with ample margin and because the manufacturer saves money buying a crate of common values.
- Your valve power amplifier uses valve rectification and employs a cap/choke/cap in the smoothing circuit. These caps are typically around 47-100uf at 450-600v. The first capacitor is having to deal with considerable ripple current close to its limits, while the second receives the filtered signal after the choke. Not only is the first capacitor running near its limits but its running next to a searingly hot rectifier. it will be completely farked in <5 years. Clearly these caps need regular replacement because low ESR is essential for low noise.
- The chip based regulator in your pre amplifier is using a small 10uf electrolytic capacitor on its output to ensure stability. Ripple is low, heat is low, and it runs well within voltage rating. ESR needs to be moderate - too low and the circuit becomes unstable - and therefore even a tripling of the original value ESR has no effect. The capacitance value isn't critical within +/- 50% limits.
If these look fine, and the circuit is quiet - it can clearly be left alone.
Actually using a modern high performance low ESR cap in this situation will often give worse performance.
Just some examples of why wholesale ripping out of electrolytics is unwise IME.
Not a view I've always held but one developed after spending a good few years ripping things to pieces and testing them
Over the weekend I'll post some actual test results for 30+year old caps. The results will surprise many - they certainly surprised me.
PS: Agree entirely with LPSpinner.
Tony L
Administrator
The capacitor thing is food for thought. My main issue as a punter is that if I'm paying a good wedge for a service I'd want the job doing to the extent the item was done for 10-20 years. I'm perhaps over-paranoid/way too OCD in this respect, but when I restore a piece of vintage kit (either myself or paying someone else to do it) my aim is to make the item as-new again, e.g. I consider myself to have a brand new Quad 303, 34 & 306, a brand new pair of JR149s etc. Getting it done right is my only priority. I can take this line of thought too far (e.g. TD-124!), but it's just how I work.
PS Check this Luxman CL-32 preamp out; silver facia, tubes and a Quad style tilt control! What's not to like?
PS Check this Luxman CL-32 preamp out; silver facia, tubes and a Quad style tilt control! What's not to like?
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flatpopely
Prog Rock/Moderator
Tony.
There is a requirement for rebuilding old amps, possibly replacing like for like with new. However indiscriminate application of this may not be the best thing, as I said with my JVC just a few tired caps replaced made a huge difference.
If an amp was rebuilt with 100% new parts then there would be no issue but that's not practical.
I used to believe in recapping until I got the JVC
P.S. If I was a amp refurbish person I'd be looking at this very closely.
There is a requirement for rebuilding old amps, possibly replacing like for like with new. However indiscriminate application of this may not be the best thing, as I said with my JVC just a few tired caps replaced made a huge difference.
If an amp was rebuilt with 100% new parts then there would be no issue but that's not practical.
I used to believe in recapping until I got the JVC
P.S. If I was a amp refurbish person I'd be looking at this very closely.