I've been poking around on the net trying to decide which SET kit I should build for my first DIY amp project. I was going to go for the Lux from diyhifisupply but I've now settled on the above. This appeals to me for a number of reasons:
- you can configure it for several different types of valve; 45, 300B, 2A3 etc.
- you just buy the PCB (at a reasonable price) so you can choose your own brand of components, and there are excellent assembly guidance notes on the website
- I really like the ethos of George Anderson. There is not even a hint of misplaced ego, bullshit or snake oilyness on the website.
- I think it will be more educational for me than the Lux kit
- the design seems really interesting and includes a CCS input circuit and a mosfet follower.
Any adverse responses will probably not affect my decision but has anyone heard one of these perchance?
Regards
Ian
TubelabSE
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Paul Barker
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#2
Congratulations you seem to have found a novel one.
5842's are expensive these 3look like you will get a good deal.
You may have trouble obtaining the mosfet.
In principle I like it and look forward to hearing it one day.
I have the option to use 45 or 2a3 at the moment but am finding the 2a3 necessary.
Don't be tempted substituting the 6c45pi for the 5842.
Since the circuit uses a ccs load for this valve there ins't really any need to use a high transconductance valve, so I would be radical and alter the circuit to employ something a low transconductance type for reasons of my own.
A quick glance of the schematic be aware the coupling cap between the 5842 and the NFET is probably meant to be 0.22 microfarad not 22 microfarad.
5842's are expensive these 3look like you will get a good deal.
You may have trouble obtaining the mosfet.
In principle I like it and look forward to hearing it one day.
I have the option to use 45 or 2a3 at the moment but am finding the 2a3 necessary.
Don't be tempted substituting the 6c45pi for the 5842.
Since the circuit uses a ccs load for this valve there ins't really any need to use a high transconductance valve, so I would be radical and alter the circuit to employ something a low transconductance type for reasons of my own.
A quick glance of the schematic be aware the coupling cap between the 5842 and the NFET is probably meant to be 0.22 microfarad not 22 microfarad.
#3
Paul
many thanks for that and I will be delighted to demo it at a Yorkshire meet at some point in 2008 assuming I can translate my respect for fast moving electrons into common sense (Did you see the page on his website about his monster prototype 833 amp - 1500v !)
Ian
many thanks for that and I will be delighted to demo it at a Yorkshire meet at some point in 2008 assuming I can translate my respect for fast moving electrons into common sense (Did you see the page on his website about his monster prototype 833 amp - 1500v !)
Ian
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Paul Barker
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#4
Exactly, a man who is prepared to take off his shirt and play his guitar through an 833 glowing far too hot is either on the right track or completely nuts.
I think he's on the right track.
Andrew was using those current IC's I wander how he got on with them?
I have no problem with a good ccs seems like he has found a good one, your amp would be a lot lighter than mine with it's 12 chokes not including the power supply! On top of which yours might sound better, it will certainly sound different which usually translates to better at just about everything else except the one thing I am listening for, which I prefer to have at the cost of everything else. Don't ask me what that is, but I know when I've got it and that's what's important.
The mosfet drive to the output stage is really not new Chris Vry was trying to get me to do it for driving the 212, probably I should have, so I've ordered a pair, you can get them on ebay. I don't think I'd bother with two stages of mosfet for me it would be sufficient to power drive the output valves, Interesting that he even finds it advantagous on the 45?
The last time I had the 212 up and running it was really driving it that was my problem, I had gone to 211 cathode follower, and it just didn't have that thing I was talking about above. Reflecting about it the best 212 sound in public was at my house some 5 years or so ago when Nick and Ali Tate were there I was using 6em7 voltage amp and cathode follower direct coupled drive. I am looking forward to finding out whether the NFET can sound like that or better.
I think he's on the right track.
Andrew was using those current IC's I wander how he got on with them?
I have no problem with a good ccs seems like he has found a good one, your amp would be a lot lighter than mine with it's 12 chokes not including the power supply! On top of which yours might sound better, it will certainly sound different which usually translates to better at just about everything else except the one thing I am listening for, which I prefer to have at the cost of everything else. Don't ask me what that is, but I know when I've got it and that's what's important.
The mosfet drive to the output stage is really not new Chris Vry was trying to get me to do it for driving the 212, probably I should have, so I've ordered a pair, you can get them on ebay. I don't think I'd bother with two stages of mosfet for me it would be sufficient to power drive the output valves, Interesting that he even finds it advantagous on the 45?
The last time I had the 212 up and running it was really driving it that was my problem, I had gone to 211 cathode follower, and it just didn't have that thing I was talking about above. Reflecting about it the best 212 sound in public was at my house some 5 years or so ago when Nick and Ali Tate were there I was using 6em7 voltage amp and cathode follower direct coupled drive. I am looking forward to finding out whether the NFET can sound like that or better.
#5
Can some post a link to the circuit?
Was the Andrew me?
5842's may break the bank, if you are driving the output valve with a solid state buffer, which I'm only guessing at, without seeing the cct then you could try a different valve.
Or, you could try a triode wired E180F instead of the 5842, these are cheap but get a few and select the ones that don't go zing when you tap them in circuit; they can be microphonic little buggars. E180F are supposed to SQ (special quality) valves as well, don't pay more than a pint of beer or so each. I paid $5 for mine.
Others are better at recommending alternatives as I tend to stick to what other recommend or stuff I can get hold of cheaply, i.e. current production.
cheers,
-- Andrew
Was the Andrew me?
5842's may break the bank, if you are driving the output valve with a solid state buffer, which I'm only guessing at, without seeing the cct then you could try a different valve.
Or, you could try a triode wired E180F instead of the 5842, these are cheap but get a few and select the ones that don't go zing when you tap them in circuit; they can be microphonic little buggars. E180F are supposed to SQ (special quality) valves as well, don't pay more than a pint of beer or so each. I paid $5 for mine.
Others are better at recommending alternatives as I tend to stick to what other recommend or stuff I can get hold of cheaply, i.e. current production.
cheers,
-- Andrew
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Paul Barker
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#6
Sorry Andrew my mind must be playing tricks, someone has tried them I'm sure, must have been someone over at WAD.
Anyhow for a beginner it's one of the simplest ways to make a ccs and might be one of the best, time will tell. Certainly the benefits of a ccs are enjoyed by many here, though at the moment I am all chokes I wouldn't like to call it. There are much greater sound advances to be had elsewhere, and the ccs is so cheap and so light. No brainer.
Yes it seems unecessarily expensive choice of voltage amplifier considering that it isn't required to provide a low impedance either to the next stage or to the load. Anything like a ecc83 or 6sl7 would do current of ccs set achordingly.. But if the 5842's can be obtained within budet easier for a first built to follow the schematic like an automaton.
Anyhow for a beginner it's one of the simplest ways to make a ccs and might be one of the best, time will tell. Certainly the benefits of a ccs are enjoyed by many here, though at the moment I am all chokes I wouldn't like to call it. There are much greater sound advances to be had elsewhere, and the ccs is so cheap and so light. No brainer.
Yes it seems unecessarily expensive choice of voltage amplifier considering that it isn't required to provide a low impedance either to the next stage or to the load. Anything like a ecc83 or 6sl7 would do current of ccs set achordingly.. But if the 5842's can be obtained within budet easier for a first built to follow the schematic like an automaton.
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Paul Barker
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#8
Yes that's what I meant, so little time we buy these things put them asside, when we do find time, we can't find them, later we find them, what are these?
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Paul Barker
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#10
Right, well I have the bits for the plasma tweeters on order. OOPS.
But I do need to check that one out like all the other things I've tried, it might be a keeper, we'll have to see, I was sure the Ariels were the end of the story before I had them.
But I do need to check that one out like all the other things I've tried, it might be a keeper, we'll have to see, I was sure the Ariels were the end of the story before I had them.
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andrew Ivimey
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#11
If I did that t'other Andrew I'd still never finish!
JAN NOS Raytheon 5842s are not the silly Mullard prices - a fiver each plus whatever it takes to get them to you or Ian. I still have some Mullard NOS E180Fs - how much is a pint these days - you are welcome!
I am running at least 6months behind on things discussed in these here pages but I was determined to at least give voltage regulation a go. So, The 'doddington special' only needs a tad under 200volt HT and a smidgeon less than 90ma, so voltage regulation was easy.
But I could only get up to about 70ma - did I care? Nope. For the couple of hours I was running the amp, before melt down became a possibility, (and I am becomming ever more willing to do anything to overcome hum,) the voltage regulator circuit took all the hum away and left just signal.
BUT, and this is my tentative conclusion, voltage regulation is sterile and NASTY and I will not bother with it again - except people like them in pre-amps - um, why! I don't know.
And we have found that CCS can do wonderful things and can ruin the sound of an amp too. very interesting. I have a couple of ixcys copies from diyhifisupply.com for experimenting with the current supply in a pair of 6N6Ps on the front end of an Amity amplifier - right now I am content to use a couple of resistors and a cap (just to get things going) and implementing the VR valve (OD3 - 150v) made things sound great .... er, VR? ... which takes me back to the beginning.
-wonder what the new year will bring? peace in Pakistan and my new O-Netics transformers.
JAN NOS Raytheon 5842s are not the silly Mullard prices - a fiver each plus whatever it takes to get them to you or Ian. I still have some Mullard NOS E180Fs - how much is a pint these days - you are welcome!
I am running at least 6months behind on things discussed in these here pages but I was determined to at least give voltage regulation a go. So, The 'doddington special' only needs a tad under 200volt HT and a smidgeon less than 90ma, so voltage regulation was easy.
But I could only get up to about 70ma - did I care? Nope. For the couple of hours I was running the amp, before melt down became a possibility, (and I am becomming ever more willing to do anything to overcome hum,) the voltage regulator circuit took all the hum away and left just signal.
BUT, and this is my tentative conclusion, voltage regulation is sterile and NASTY and I will not bother with it again - except people like them in pre-amps - um, why! I don't know.
And we have found that CCS can do wonderful things and can ruin the sound of an amp too. very interesting. I have a couple of ixcys copies from diyhifisupply.com for experimenting with the current supply in a pair of 6N6Ps on the front end of an Amity amplifier - right now I am content to use a couple of resistors and a cap (just to get things going) and implementing the VR valve (OD3 - 150v) made things sound great .... er, VR? ... which takes me back to the beginning.
-wonder what the new year will bring? peace in Pakistan and my new O-Netics transformers.
Last edited by andrew Ivimey on Sun Dec 30, 2007 12:40 pm, edited 2 times in total.
#12
Ok, but assuming it didn't melt down, try with a 10R resistor into a good elect or film cap, maybe 20uf or so, then take the amp supply from that combination.BUT, and this is my tentative conclusion, voltage regulation is sterile and NASTY and I will not bother with it again - except people like them in pre-amps - um, why! I don't know.
You may still not like it, but I would be interested in your findings.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
#13
Hi Andrew,andrew Ivimey wrote: JAN NOS Raytheon 5842s are not the silly Mullard prices - a fiver each plus whatever it takes to get them to you or Ian. I still have some Mullard NOS E180Fs - how much is a pint these days - you are welcome!
Sold, can you save me a pair or four, if you have them to spare, until we next meet up? I should have got around to needing them by then.......to drive the LCR on the phono.
ta,
t'other.
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andrew Ivimey
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#14
Okay, Andrew Mact'other.
Nick, this is adding what is effectively an(RC) filter then and this helps matters (?). I will try what you suggest, eventually.
Right now I have put the Dodd. back together again though using choke, cap, choke, cap for PS. There is no hum but a tiny hint of a whisper and the amplifier sounds a lot better
I'm using a pair of 208s in front loaded horns 15 inches deep by 36 high. They sound marvellous - such bass, albeit in quite a small room. But there is a lot missing in the top - supertweeters needed!
Beginner's question:- why don't we use big caps (after the choke) in valve amplifiers PSUs like they do with SS? What does, say, a 1000mfd cap bring to the valve amplifier (particularly SE, I suppose) that is undesirable?
Nick, this is adding what is effectively an(RC) filter then and this helps matters (?). I will try what you suggest, eventually.
Right now I have put the Dodd. back together again though using choke, cap, choke, cap for PS. There is no hum but a tiny hint of a whisper and the amplifier sounds a lot better
I'm using a pair of 208s in front loaded horns 15 inches deep by 36 high. They sound marvellous - such bass, albeit in quite a small room. But there is a lot missing in the top - supertweeters needed!
Beginner's question:- why don't we use big caps (after the choke) in valve amplifiers PSUs like they do with SS? What does, say, a 1000mfd cap bring to the valve amplifier (particularly SE, I suppose) that is undesirable?
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Paul Barker
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#15
your 208 speakers sound interesting.andrew Ivimey wrote: I'm using a pair of 208s in front loaded horns 15 inches deep by 36 high. They sound marvellous - such bass, albeit in quite a small room. But there is a lot missing in the top - supertweeters needed!
Beginner's question:- why don't we use big caps (after the choke) in valve amplifiers PSUs like they do with SS? What does, say, a 1000mfd cap bring to the valve amplifier (particularly SE, I suppose) that is undesirable?
supertweeters needed here too
1,000 uf caps of high sound quality scarcity I suppose.