That's an expensive way to mount a chipamp to a heatsink.
It shows that Cambridge were concerned about chip temperature and were prepared to expend that money on reliability that has no measurable effect on the usual specifications published by manufacturers.
It shows that Cambridge were concerned about chip temperature and were prepared to expend that money on reliability that has no measurable effect on the usual specifications published by manufacturers.
Hi Stream,
You can only directly import one photo per post. You can use links to an external file server to link many photos. That would be the button beside the [[url]http://[/url]] button. You have used the "Attach File" function so far. Only one per post.
Your photo shows that they used NP0 / C0G capacitors for the ceramic capacitors. That shows some attempt at preserving some sound quality. C3 is large to try and retain the very low cutoff point. I'll bet they were worried about phase more than the lower -3dB point. If you can use some higher value film caps there, rather than the electrolytic, that would help. I know that 6.8 uF 50V caps are available with a 5mm lead spacing. That would be better than a 2.2 uF. Not the end of the world either way.
-Chris
You can only directly import one photo per post. You can use links to an external file server to link many photos. That would be the button beside the [[url]http://[/url]] button. You have used the "Attach File" function so far. Only one per post.
Your photo shows that they used NP0 / C0G capacitors for the ceramic capacitors. That shows some attempt at preserving some sound quality. C3 is large to try and retain the very low cutoff point. I'll bet they were worried about phase more than the lower -3dB point. If you can use some higher value film caps there, rather than the electrolytic, that would help. I know that 6.8 uF 50V caps are available with a 5mm lead spacing. That would be better than a 2.2 uF. Not the end of the world either way.
-Chris
Hi Mike,
Have a good listen to jaycee. The man has a lot of experience and is trying to bring a balanced approach towards what you have there.
May I make a suggestion here? In order to retain some sanity and the market value of your amp, just do "upgrade light". Simply replace some components with better. Don't install really expensive parts and forget the transformer for now.
A few people have tried to show you the limitations of this amplifier. You have electronic source switching. This will mess up the sound more than your volume control, transformer or anything else going on there. What I am suggesting is to do some small things to improve the sound quality and retain the original build.
Now what? You haven't done your upgrades that you so desperately want to accomplish. Well, time to build your own amp. It's the only way to control things like input switching, power supplies and PCB trace routing. The only way you will actually get anywhere positive is to build one from the ground up. Heck, the cost will be close, so you may as well end up with a bedroom system and a listening system. What you will end up with is a nice Cambridge system that works, and a great little amp that sounds far better and the pride of putting a complete one together. Also, as you work on the super amp, you will still have sound in the house. You won't be pressured to build things fast in a rush.
The reason I am leaning this way is that I can see you want to go "no holds barred" with your amp project. Since this is the case, your money is far better spent building new as there are some things in the commercial amp that are road blocks to really good sound. You will have a pile of parts left over from a modification that is almost close enough to build another unit. Think about this. Transformer, filter caps, volume control and all small bits. You are only missing a case, heat sink and the chips to make a complete amp.
-Chris
Have a good listen to jaycee. The man has a lot of experience and is trying to bring a balanced approach towards what you have there.
May I make a suggestion here? In order to retain some sanity and the market value of your amp, just do "upgrade light". Simply replace some components with better. Don't install really expensive parts and forget the transformer for now.
A few people have tried to show you the limitations of this amplifier. You have electronic source switching. This will mess up the sound more than your volume control, transformer or anything else going on there. What I am suggesting is to do some small things to improve the sound quality and retain the original build.
Now what? You haven't done your upgrades that you so desperately want to accomplish. Well, time to build your own amp. It's the only way to control things like input switching, power supplies and PCB trace routing. The only way you will actually get anywhere positive is to build one from the ground up. Heck, the cost will be close, so you may as well end up with a bedroom system and a listening system. What you will end up with is a nice Cambridge system that works, and a great little amp that sounds far better and the pride of putting a complete one together. Also, as you work on the super amp, you will still have sound in the house. You won't be pressured to build things fast in a rush.
The reason I am leaning this way is that I can see you want to go "no holds barred" with your amp project. Since this is the case, your money is far better spent building new as there are some things in the commercial amp that are road blocks to really good sound. You will have a pile of parts left over from a modification that is almost close enough to build another unit. Think about this. Transformer, filter caps, volume control and all small bits. You are only missing a case, heat sink and the chips to make a complete amp.
-Chris
Very true. I think I'll just go with a few tweaks such as better local decoupling caps and good quality resistors. When I take a few measurements I can determine if things like losing the NFB cap is viable. I can try some film bypass on the Smoothing caps too. I know I can loose a few decoupling caps from the signal path due to the low DC on the output of the LM4562. A better pot wouldnt hurt either. Its funny you mention the input switcher chip as I have had considerations on this myself. This is probably the most limiting factor on the amp. A couple of low noise regs will probably help it and the opamp though.
I wonder if I could replace the switcher for a set of reed relays...........Kidding of course!
I wonder if I could replace the switcher for a set of reed relays...........Kidding of course!
Mike, what kind of skills do you have at your disposal? I'm guessing electronics wise, you would be able to assemble kits, as you have done all these mods fairly well.
What about other things, like metalwork? Mainly I mean drilling holes accurately in thick metal, and mounting parts. One thing that often puts people off DIY builds is being able to case the stuff in something attractive looking. There are sellers who cater for this market, such as www.modushop.biz (the Pesante cases are gorgeous!) but you still need to be able to do some extra work.
What about other things, like metalwork? Mainly I mean drilling holes accurately in thick metal, and mounting parts. One thing that often puts people off DIY builds is being able to case the stuff in something attractive looking. There are sellers who cater for this market, such as www.modushop.biz (the Pesante cases are gorgeous!) but you still need to be able to do some extra work.
I can do all of these things pretty well. I can read schematics also. I have an engineering backgroud so given the right tools I could build something akin to a Peter Daniel special probably. Mouldshop, yes their cases are very nice. I have one infront of me now from a little starter project I had a while ago.
http://www.diyaudio.com/forums/showthread.php?s=&postid=1645019#post1645019
http://www.diyaudio.com/forums/showthread.php?s=&postid=1645019#post1645019
Hi jaycee,
Hey! Prototype heaven! They even have CD chassis, too bad they are not in North America.
-Chris
Hey! Prototype heaven! They even have CD chassis, too bad they are not in North America.
-Chris
Stream said:
Hi Stream,
I can't see your transformer in either photo, but the way the chip is mounted is great!
You can only upload one photo per post, unless you hotlink them from another host.
Hi Mike,
It sounds like you're now leaning towards something more DIY, which I'm very pleased about. If you want to keep things fairly simple a LM3886 with good power supplies, driven by the buffer Pedja Rogic (?) designed will sound loads better than your CA. You can put S Powers on that buffer and it sounds amazing! Point to point wiring is easy on an LM3886 too if that interests you.
There are also fun options for fancy remote volume and switching controls around. You could make a really, really smart and excellent sounding integrated amp for fairly sensible cash.
Simon
mikesnowdon said:
So, you easily possess the skills to build from scratch. I'd go for it 🙂 You might even consider more than a Gainclone, especially if your TDL speakers like to be driven by a bit more than 40/50W of power. There's plenty of options - that's the best part about DIYing it 😉
anatech said:
Yeah, the Pesante case is what I'd really like to put my amps into - but the VAT tax and shipping costs are nasty, even from italy to the UK
Pesante Dissipante would be ideal for the perfect 100W per channel amp i'd love to build!
Hi Jaycee.
Diy Hi-Fi do a nice case.
Link
Diy Hi-Fi do a nice case.
Link
An externally hosted image should be here but it was not working when we last tested it.
That is nice, but at £110 I'd rather go with the Modushop cases, which are sprayed and finished nicely.
Those cases do look like you could run a tank over them and not dent them, though 🙂
Those cases do look like you could run a tank over them and not dent them, though 🙂
Ok so Im going to build a nice amp from scratch at some point.
In the meantime lets put together a list of possible mods which would improve the CA 340A without going over the top:
Poweramp PSU:
- Change the diodes to MUR860.
- Add good quality film bypass caps to the main smoothers.
- Add a pair of Panasonic FC or simmilar (220-470uF) low ESR cap at the main smoothers.
- Upgrade local decoupling caps at the chips to BG N 100uF 50v.
Power stage:
- Upgrade resistors.
- Change LM3886 config to Peter Daniels. (No NFB cap etc)
Preamp:
(Allready has improved opamp and film dc blocking caps)
- Remove DC blocking caps from signal path exept the final pair infront of the power stages. (currently each channel has 4 caps in the signal path. DC output from LM4562 is low enough to remove most of these)
- 10uf 25v BG N local decoupling on opamp and selector chip.
- Upgrade resistors around opamp.
- Upgrade Ceramic feedback caps on opamp.
- Fit low noise regs at preamp PSU.
- Power rail traces to Regs are very thin. Possibly I could remove the solder mask and apply silver solder to the traces to improve their conductivity.
- Fit Alps Blue volume pot.
- Upgrade balance pot.
- Copper binding posts.
- Silver RCA's
- Oak cone feet on chassis.
- Bitumin resonance control.
- Upgrade volume knob to a 840A one!
I will update the above list as suggestions or advice are given.
Any comments?
Mike.😀
In the meantime lets put together a list of possible mods which would improve the CA 340A without going over the top:
Poweramp PSU:
- Change the diodes to MUR860.
- Add good quality film bypass caps to the main smoothers.
- Add a pair of Panasonic FC or simmilar (220-470uF) low ESR cap at the main smoothers.
- Upgrade local decoupling caps at the chips to BG N 100uF 50v.
Power stage:
- Upgrade resistors.
- Change LM3886 config to Peter Daniels. (No NFB cap etc)
Preamp:
(Allready has improved opamp and film dc blocking caps)
- Remove DC blocking caps from signal path exept the final pair infront of the power stages. (currently each channel has 4 caps in the signal path. DC output from LM4562 is low enough to remove most of these)
- 10uf 25v BG N local decoupling on opamp and selector chip.
- Upgrade resistors around opamp.
- Upgrade Ceramic feedback caps on opamp.
- Fit low noise regs at preamp PSU.
- Power rail traces to Regs are very thin. Possibly I could remove the solder mask and apply silver solder to the traces to improve their conductivity.
- Fit Alps Blue volume pot.
- Upgrade balance pot.
- Copper binding posts.
- Silver RCA's
- Oak cone feet on chassis.
- Bitumin resonance control.
- Upgrade volume knob to a 840A one!
I will update the above list as suggestions or advice are given.
Any comments?
Mike.😀
Looking good Mike. Personally speaking, I'd not use Pana Fc or any film caps unless in series with a resistor (snubber network). Those other mods should transform the sound. The best thing may well be the oak cone feet, which make a lovely difference you can't get any other way. Edit: just seen the signal goes through FOUR caps!!!! Wow, that will be night and day binning those off!!!
Simon
Simon
Bummer
I was thinking: If we are trying to reduce impeidance on the PSU, I could remove a few of the fuses perhaps? I would leave the fuse on the Live input to the trafo and bin the rest?
Mike.
I was thinking: If we are trying to reduce impeidance on the PSU, I could remove a few of the fuses perhaps? I would leave the fuse on the Live input to the trafo and bin the rest?
Mike.
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