Hi everyone, I recently purchased a Denon HA-1000 mc headamp. It's in great condition, working fine and sounding fantastic.
I opened her up and there is either some mild leaking of some EL caps but it could also just be glue. Most of the edges are really smooth so that probably means glue. There is one place where some crystals are showing so that area is probably from a minor leak. All the other caps show no signs of glue or leaks. The unit is probably from the late 70s or early 80s so some preventative recapping is not terrible idea.
I've found a schematic online and I'm looking at what I might want to change. I really like the sound so I don't want to change too much right away, but I am open to discussion if there is something (like improved voltage regulations) which could elevate the sound. In general I don't like the shotgun approach of changing everything at once. I'll just start with a few select locations where the caps could be leaking or stressed from age, or where I think a more modern cap can be an improvement.
My plan so far is to focus on the rather generic black wrapper chemicon larger caps. I want to do Panasonic FR for the outboard PSU (2200uf/35v: C4,C5), the larger rail bypasses (1000uf:C11,C12; 2200uf:C7,C8,C9,C10,C33,C34,C35,C36; 330uf:C13,C14) and I'm also thinking about Panasonic OSCON for the input blocker caps (470uf/6.3v: C1,C2,C3,C4) and maybe for the 1000uf at C15,C16 which I think might be part of the feedback loop. The input caps are too big a uf value for film caps, so I think OSCON is a reasonable upgrade. Since it is just a MC headamp there is no RIAA circuit.
I still need to measure the diameters of the caps and lead spacing so I am in no rush. I'm just at a planning and thinking stage now.
I'm searching for some discussion on the circuit. Is there some other parts I should focus on?
After the initial re-capping, is there some part of the circuit that could use an upgrade like improved voltage regulation.
cheers jeshi
I opened her up and there is either some mild leaking of some EL caps but it could also just be glue. Most of the edges are really smooth so that probably means glue. There is one place where some crystals are showing so that area is probably from a minor leak. All the other caps show no signs of glue or leaks. The unit is probably from the late 70s or early 80s so some preventative recapping is not terrible idea.
I've found a schematic online and I'm looking at what I might want to change. I really like the sound so I don't want to change too much right away, but I am open to discussion if there is something (like improved voltage regulations) which could elevate the sound. In general I don't like the shotgun approach of changing everything at once. I'll just start with a few select locations where the caps could be leaking or stressed from age, or where I think a more modern cap can be an improvement.
My plan so far is to focus on the rather generic black wrapper chemicon larger caps. I want to do Panasonic FR for the outboard PSU (2200uf/35v: C4,C5), the larger rail bypasses (1000uf:C11,C12; 2200uf:C7,C8,C9,C10,C33,C34,C35,C36; 330uf:C13,C14) and I'm also thinking about Panasonic OSCON for the input blocker caps (470uf/6.3v: C1,C2,C3,C4) and maybe for the 1000uf at C15,C16 which I think might be part of the feedback loop. The input caps are too big a uf value for film caps, so I think OSCON is a reasonable upgrade. Since it is just a MC headamp there is no RIAA circuit.
I still need to measure the diameters of the caps and lead spacing so I am in no rush. I'm just at a planning and thinking stage now.
I'm searching for some discussion on the circuit. Is there some other parts I should focus on?
After the initial re-capping, is there some part of the circuit that could use an upgrade like improved voltage regulation.
cheers jeshi
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Hello,
IF it sounds fantastic i would not change to much.
If the capacitors are not stressed at all by high temperature of the surroundings or high current needed by the circuit they still can be very good.
Changing the input capacitor could improve the sound but you will have to be careful and use the right one. I dont know which one that will be.
Of course there will be people who will tell you to upgrade the power supply. There are some tiny boards available that could do the trick but then you could end up with '' destroying '' the inside looks of your device. AND you will need the knowledge or the help of some people to do it right.
Maybe there are some switches that you dont need and that could be bypassed?
Greetings, eduard
IF it sounds fantastic i would not change to much.
If the capacitors are not stressed at all by high temperature of the surroundings or high current needed by the circuit they still can be very good.
Changing the input capacitor could improve the sound but you will have to be careful and use the right one. I dont know which one that will be.
Of course there will be people who will tell you to upgrade the power supply. There are some tiny boards available that could do the trick but then you could end up with '' destroying '' the inside looks of your device. AND you will need the knowledge or the help of some people to do it right.
Maybe there are some switches that you dont need and that could be bypassed?
Greetings, eduard
thanks eduard, good to know that the caps might actually still be ok even after 40years if they are not stressed.
I might just do the bypass capacitors at some point this year and leave the input capacitors alone for a while. Changing these united chemicon 2200uf, 1000uf and 330uf caps to something like Panasonic FR should have minimal affect on the sound but they might clean up the power a little. Should be reasonably safe maintenance.
I use all the functions on this unit so I need all the switches. Some of the switches are startup timed relays, some are switching the gain of the unit or bypassing when using a MM cartridge.
Here is some info on the HA-1000. It's in Japanese though sorry.
https://audio-heritage.jp/DENON/etc/ha-1000.htmlI'm still pretty much a beginner/hobbiest when it comes to circuits so I'm always open to learning more.
cheers jessica
I might just do the bypass capacitors at some point this year and leave the input capacitors alone for a while. Changing these united chemicon 2200uf, 1000uf and 330uf caps to something like Panasonic FR should have minimal affect on the sound but they might clean up the power a little. Should be reasonably safe maintenance.
I use all the functions on this unit so I need all the switches. Some of the switches are startup timed relays, some are switching the gain of the unit or bypassing when using a MM cartridge.
Here is some info on the HA-1000. It's in Japanese though sorry.
https://audio-heritage.jp/DENON/etc/ha-1000.htmlI'm still pretty much a beginner/hobbiest when it comes to circuits so I'm always open to learning more.
cheers jessica
C1 - 4 and C29 - 32 are in the signal path and will effect the sound. The rest are all power supply or local power supply bypass caps. They bigger supply caps will have lost some capacitance by now. The input and output caps largely determine the sound so if you replace them do it so you can put them back in if you don’t like the change. Modern PS caps are a lot better than the old ones so change those out with new ones that fit. Use the same or higher voltage, same uF. You can bypass the input and output caps with some small polystyrene caps to make them a little faster giving you better highs but that is totally subjective. The unit is well built and well designed so don’t mess with the circuit itself. The PS caps should give you lower noise and cleaner sound. The input and output caps will give you more clean detail. Just enjoy your new hobby. It will become an obsession if you are not careful and remember it’s all about the music not the technical numbers. If it sounds good to you that’s what matters!
That’s a pretty cool old amp there. What you are saying and what you are planning on doing are different things. The parts you are planning on replacing are likely standard types of parts. Both the oscon and fr are both extremely low esr parts, and may not play nicely, or may even cause oscillations if used in certain parts of that circuit.
I’d probably stick with more standard parts until you really know the circuit, like the designer did.
Not saying that because I am against modifying things by any means however…
I’d probably stick with more standard parts until you really know the circuit, like the designer did.
Not saying that because I am against modifying things by any means however…
thanks so much. I'm glad to hear this is such a well designed and well built circuit and doesn't need any "tweaking". I'm still a little worried about those leaky capacitors in the photos.
Am I correct in thinking that replacing just the power supply and local power supply bypass caps with something modern like a Panasonic FR or FM shouldn't cause problems and it is good idea given the age of the unit? Or is "phase" correct above saying that the Panasonic FR is too low an ESR, might cause oscillations and that I should replace with a similar grade of bypass capacitor (maybe Panasonic FC)? I thought low ESR is a good thing for a local power supply bypass capacitor.
I will definitely be very cautious about changing anything in the signal path. I do like the idea of playing with bypassing the input/output caps with some parallel polystyrene or other caps (paper-oil, PP etc) to see if I like the change in sound. It would be easy to reverse (un-solder) if I don't like them and I would not have modified the original circuit.
thanks everyone
will a low ESR capacitor cause oscillation problems in a simple local power supply bypass? I can see how a lower ESR capacitor might cause problems when in series in the signal path (like a blocking capacitor), but when tied to ground as a power supply bypass I thought that would be ok?
This is an interesting discussion! Several different nuances of recapping theory that are new to me. Thanks
Might be a better plan to get a kit board and try all this stuff on it before experimenting on vintage gear.
And keep reading, searching all your ideas, many have tried these things before and with a better understanding, you can make more informed decisions about what to try and where.
And keep reading, searching all your ideas, many have tried these things before and with a better understanding, you can make more informed decisions about what to try and where.
sorry I have tried several kits and just never completed them (phono boards, amp boards...). I'm friends with @xrk971 and he has tried to get me to build several amps and circuits. I'm really just looking for some advice on re-capping my denon HA-1000. I shouldn't have add in the part about "improving" the circuit. I was just hoping to get some feedback on the circuit and how people here think about it.
I would just get parts that are more standard replacement and enjoy that amp, low esr parts aren’t going to improve much there, and have a risk of more noise, stress on other parts.
I have alway purchased the kits complete, that way they at least work, then can be changed if desired later. I should have mentioned that before.
I have alway purchased the kits complete, that way they at least work, then can be changed if desired later. I should have mentioned that before.
like here is a blog post from a guy who recapped his HA-1000 but he just changed everything with nichicon audio grade which seems a bit random and he mentioned the sound changed a lot.
https://bmwkrs.exblog.jp/22825838/I'm trying to get some more information before I do anything
https://bmwkrs.exblog.jp/22825838/I'm trying to get some more information before I do anything
ok now I understand what you are saying. thank you
I live in tokyo and there are some shops in akihabara which sell nichicon and chemicon capacitors like the united chemicon KMG. that way I can just pick up a few and not worry about placing a large order with mouser
Parts like that are likely what was used back when it was made.
I would do one thing at a time, and then give it a couple weeks of listening store making another change.
That can be more work, but not if something changes in a bad way and you then need to correct it. The audio branded parts usually have less noise, yet are not without their own character. Often if all of the parts are one type and brand, it can be less desirable, a mix seem to be better, wider range of that makes sense.
I would do one thing at a time, and then give it a couple weeks of listening store making another change.
That can be more work, but not if something changes in a bad way and you then need to correct it. The audio branded parts usually have less noise, yet are not without their own character. Often if all of the parts are one type and brand, it can be less desirable, a mix seem to be better, wider range of that makes sense.
I checked my photos and it looks like they are Nippon chemicon SL and ST series capacitors. They aren't made anymore and I haven't found spec sheets but I did find this seller of NOS SL which says they are long life low ESR milspec capacitors.
https://richelectronics.co.uk/produ...electrolytic-capacitor-1000uf-16v-85c-mbe002fI'll keep searching for more information on the ST series.
I might also just send an email to Nippon Chemicon and ask them what a modern equivalent for the ST and SL series would be.
https://richelectronics.co.uk/produ...electrolytic-capacitor-1000uf-16v-85c-mbe002fI'll keep searching for more information on the ST series.
I might also just send an email to Nippon Chemicon and ask them what a modern equivalent for the ST and SL series would be.
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That sounds like a good plan to ask Nippon for information. Is always good to have as much information as possible before making changes.
I wonder what was considered “low esr” in 1977?
That part, being part of the feedback portion, will likely have a larger effect on the sound/stability of the amp. If I see it correctly, that is.
I wonder what was considered “low esr” in 1977?
That part, being part of the feedback portion, will likely have a larger effect on the sound/stability of the amp. If I see it correctly, that is.
Hello,
I have a friend with an Hiraga power amplifier i build for him more than twenty years. After some small changes i told him we could try to change the caps in the power supply by Kemet top of the line caps. The original caps were one of the best available back then.
Conclusion the old caps were way better according to my friend.
You will be able to find a few new caps that will be better than the old ones. BUT surely not every new high grade cap will gave you an improvement.
IF the present caps are almost dead a newer one would be better. But you can just start replacing the ones that are important.
Of course the caps located on the input will probably make a big difference.
Somewhere i read that changing the cable at the output of the circuit ( probably the one going to the cinch chassis part) is one of the biggest improvements to be made.
Of course the best thing to do is just skip the connector and have the output cable running from the circuitboard of the HA1000 and just use a cinch plug to connect it to your phono pre amp just like Denon did with the AU310 mc transformer.
Greetings,Eduard
I have a friend with an Hiraga power amplifier i build for him more than twenty years. After some small changes i told him we could try to change the caps in the power supply by Kemet top of the line caps. The original caps were one of the best available back then.
Conclusion the old caps were way better according to my friend.
You will be able to find a few new caps that will be better than the old ones. BUT surely not every new high grade cap will gave you an improvement.
IF the present caps are almost dead a newer one would be better. But you can just start replacing the ones that are important.
Of course the caps located on the input will probably make a big difference.
Somewhere i read that changing the cable at the output of the circuit ( probably the one going to the cinch chassis part) is one of the biggest improvements to be made.
Of course the best thing to do is just skip the connector and have the output cable running from the circuitboard of the HA1000 and just use a cinch plug to connect it to your phono pre amp just like Denon did with the AU310 mc transformer.
Greetings,Eduard
If you have the meter to measure the power supply caps, unsolder one and see how far gone it is. If close, don’t worry about them. Any modern cap is likely to have a lower ESR than those old caps and since this is an audio frequency preamp I doubt you will get into trouble with too fast a cap. Remove the parts so you can reuse them if you don’t like what you hear. Try the bypass caps on the signal path caps. Yes, all caps effect the signal but the ones in which the signal enters and exits the preamp are what I’m talking about. You will end up with a sound that has more transparency and darker background allowing you to hear more low level detail. Preamps are not hard on power supplies like amps are so just replace the caps with the modern equivalent according to the manufacturer and don’t oversize them as many like to do, there is a reason they were that size. Do one step at a time and listen for a while. If it you like it keep it. Like is said before, it only matters if you like the sound not some know it all telling you what you should like.