Valve amplification to go with Garrard 401

[selfaddict]

I recently read this article and thought that there might be a change to try valve amplification with my speakers after all ;) .

http://www.symphonysound.com/articles/tubefriendly.html

I have not managed to find impedance chart to my speakers(nominal impedance 4 ohm), but it seems that Dali Helicon 800's are not especially "hard to drive" so I might get away with 30W per channel or so.

The one and only source for me is my Garrard 401 and I am now looking for suitable integrated valve amplifier to go with it.

Any recommendations?

[Ali Tait]

That's an interesting article but there's no substitute for just having a go and seeing if it works.Also,many valve amps will have 4 and 8 ohm taps,and it's worth trying both with your speakers to see which works best for you.If you haven't used valve amps before,you need to hear single ended designs against push pull to see which you prefer before deciding on a particular amp.

[colinB]

I cant help you mate but i have to thank you for digging out an interesting article.
Recently started using a Icon Audio valve phono stage and love it. Ive asking the same question, could a valve amp drive my AVI neutrons , speakers that the manufacturer states can only be properly driven by a100w amp.:scratch:

[selfaddict]

That's an interesting article but there's no substitute for just having a go and seeing if it works.Also,many valve amps will have 4 and 8 ohm taps,and it's worth trying both with your speakers to see which works best for you.If you haven't used valve amps before,you need to hear single ended designs against push pull to see which you prefer before deciding on a particular amp.

I totally agree with home demo idea, BUT because I am living in a isolated island in the middle of Irish sea it is impossible unless you risk the gear breaking during transportation :(.

What I have read about tube amplification so far, it seems that I need to forget SE design because of low output power and concentrate my search to the PP. I really like my current speakers(as does my wife), so I need to re-built my system back to front. Or actually only the middle part is missing :).

[selfaddict]

I cant help you mate but i have to thank you for digging out an interesting article.
Recently started using a Icon Audio valve phono stage and love it. Ive asking the same question, could a valve amp drive my AVI neutrons , speakers that the manufacturer states can only be properly driven by a100w amp.:scratch:

It is a bit of a gamble I think(I have the same problem) and only way to find out will be to have a home demo unfortunately :rolleyes:. My speakers are recommended by Dali to have amplification between 50-400W.

Actually now I started to think are these speaker manufacturer recommendation on 8 or 4 ohm impedance :scratch:

[colinB]

I heard a demo of your speakers at the ( cough!) what hi fi show and they sounded great. The Danish guy was on his own in a small crap room and had to borrow a av reciever of the Denon people and still managed a better sound than the Cyrus and Naim room! Always fancied a pair, best demo i heard.

[Ali Tait]

A transmitter valve SE amp would provide enough power I would think.What kind of music do you listen to?

[selfaddict]

A transmitter valve SE amp would provide enough power I would think.What kind of music do you listen to?

This is getting interesting :).

My music taste is mainly female vocal and light rock/pop, occasional classical music. So should not be hard for the amp. No heavy base or tecno music at all :spew:

[Ali Tait]

In that case I'd say an SE amp would suit you better,though I'd advise a visit to a dealer to hear both types of amp with your speakers to see which you prefer.I would say you'll probably get away with less power than you think.I used to have a Mr Liang 845 which was a great amp,and it was just up for sale this week by the chap I sold it to,though I think he's got a buyer now.If you find you prefer SE,something like that would be suitable I think.Not all Chinese stuff is poor quality,the Liang stuff is good,but I don't think it's made anymore.Perhaps you could get some Ming Da monoblocks through a British dealer.You'd pay a bit more,but you'd have the peace of mind of a guaruntee.Another option is I could put you in touch with someone who could build you a superb 211 SE amp that runs in A2,giving about 32w a channel.That would be my choice,this chap's amps really are world class.He's currently building me a pair of direct coupled amps to drive my electrostatics.

[DSJR]

If you've never owned valve gear before, then my advice would be something like one of the WD amps ready made - not expensive, easily tweaked later and a forum to help you with advice..

I'm not sure how any transformer coupled valve amp will be with 4 Ohm speakers as this technology was designed for 15 Ohm models ideally. Even with 4 Ohm transformer tappings, the amp's output impedance will be rather high and this will have an effect on the speaker crossover points I'm told.

You could do even better than "just" a valve amp and try a Croft Series 25/7 pre and power. You'd get a great phono stage too with this pair and hopefully the output stage would deal with a modern 4 Ohm speaker better too.

P.S. Garrard 401's go with ANYTHING as long as the plinth is suitable in keeping motor and idler-noise down.

[John]

I think your system should sound pretty special with the new amp Ali keep us posted and please add pics too

[Ali Tait]

I certainly hope so John,or I've wasted a lot of money! I will put put up pics etc as soon as,but don't hold your breath,it'll be a while yet.

[Ali Tait]

If you've never owned valve gear before, then my advice would be something like one of the WD amps ready made - not expensive, easily tweaked later and a forum to help you with advice..

I'm not sure how any transformer coupled valve amp will be with 4 Ohm speakers as this technology was designed for 15 Ohm models ideally. Even with 4 Ohm transformer tappings, the amp's output impedance will be rather high and this will have an effect on the speaker crossover points I'm told.

You could do even better than "just" a valve amp and try a Croft Series 25/7 pre and power. You'd get a great phono stage too with this pair and hopefully the output stage would deal with a modern 4 Ohm speaker better too.

P.S. Garrard 401's go with ANYTHING as long as the plinth is suitable in keeping motor and idler-noise down.

Couple of things here- I agree about the WD stuff,the problem is they are not replying to calls and emails at the moment,which does not bode well.Also,only PP amps are available from them in the power required.

As for the impedance issue,my statics go down to less than 2 ohms in the treble,yet sound better on the 8 ohm taps of every valve amp I've used on them.I don't think it's fair to make sweeping statements like that,it's always best to actually try it and see how it goes.

Also,I don't think valve amps are "just" anything! I'm sure the Croft stuff is great,but I doubt it gets anywhere near the best that Nick builds.As I've said before,it may be great value for money,but it's built to a price as Glenn has to make a living! Nick has no such contraints,it's just something he enjoys doing.For example,his 211 amp,given the quality of transformers and parts used to build it,if it was produced commercially,I reckon it could retail around the 10k mark.The sound quality alone would certainly justify such a price tag IMO.

[Marco]

Hi Ali,


I'm sure the Croft stuff is great,but I doubt it gets anywhere near the best that Nick builds.


I totally agree with where you're coming from, but I suspect some of it might once it's been judiciously fettled, like my own Croft has. The Charisma-X is a great circuit, sonically restricted purely (as you say) by commercial economy.

That's why I use people like Nick, Anthony TD and Duncan to fit nice juicy caps, hugely over-specced PSUs, and quality stepped attenuators inside, which effectively make my preamp comparable with the best D.I.Y designs.

Ian Walker tells me that Nick's new 'cost-no-object' preamp is sensational. I don't doubt it, and I look forward to hearing it against my Croft when it's finalised and he brings it round to Ian's. It'll act as a very good benchmark! :)


As I've said before,it may be great value for money,but it's built to a price as Glenn has to make a living! Nick has no such contraints,it's just something he enjoys doing.For example,his 211 amp,given the quality of transformers and parts used to build it,if it was produced commercially,I reckon it could retail around the 10k mark.The sound quality alone would certainly justify such a price tag IMO.

Yup - and the same goes for the copper amp. Anthony may sell these commercially, but he doesn't sell his kit for anything like it could fetch through a hi-end dealership. The 211 is a stunning amp too, and I know exactly what it's capable of through a big pair of Tannoys.....! :eek:

However, that aside, I also know from experience that for commercial products built to a price which can't compare to high quality D.I.Y designs built from scratch with no such restrictions, Croft amps punch way, way above their price tag, sonically.

I mean what other manufacturer supplies a high-quality, hard-wired, valve preamp with a superb built-in phono stage for £350? :mental:

And his top £1500 preamp, the 25R, which I've heard, is easily as good as most rival commercial designs at up to £3k - and most of those are line-only!!

So whilst agreeing with you, Ali, I can also sympathise with where Dave is coming from.

Marco.

[Ali Tait]

Yes indeed Marco,I don't disagree with anything you've said,but if you get someone to mod one of Glen's designs,then it's no longer his design,but something different.The point behind my remarks though was for the OP,and where IMO he could get the best bang for his buck.

[Marco]

I agree, Ali, but my point is that you're not changing the design, as such; it's still Glenn's circuit, so the design stays the same - all one is doing is fitting better quality components of the same value in order to release the full sonic potential of the circuit, and thus hear what it's capable of :)

This is precisely what I've done with my Croft C-X.

I'm totally with you on your last sentence, dude :cool:

Marco.

[DSJR]

Couple of things here- I agree about the WD stuff,the problem is they are not replying to calls and emails at the moment,which does not bode well.Also,only PP amps are available from them in the power required.

As for the impedance issue,my statics go down to less than 2 ohms in the treble,yet sound better on the 8 ohm taps of every valve amp I've used on them.I don't think it's fair to make sweeping statements like that,it's always best to actually try it and see how it goes.

Also,I don't think valve amps are "just" anything! I'm sure the Croft stuff is great,but I doubt it gets anywhere near the best that Nick builds.As I've said before,it may be great value for money,but it's built to a price as Glenn has to make a living! Nick has no such contraints,it's just something he enjoys doing.For example,his 211 amp,given the quality of transformers and parts used to build it,if it was produced commercially,I reckon it could retail around the 10k mark.The sound quality alone would certainly justify such a price tag IMO.

it has been shown that transformer coupled amps, which have a highish output impedance as a matter of course, will firstly give less damping to lower impedance speakers, and, apparently alter the effects of the passive crossover network, raising the bass roll-off and lowering the treble one. Whether this is an issue with the OP's speakers is a matter for him to decide, but the facts are measurable if anyone cares to attempt it. This isn't about impedance dips outside the crossover "overlap" but at the frequencies where our ears are working.

Isn't saying that Glenn's designs "can't" be as good as Nick builds also a sweeping statement sir? I mean, I doubt you've heard Glenn's stuff any more than I've heard Nick's..... Glenn's designs are very simple with nothing superfluous needed or added. Just what I believe a circuit should be - and if it's a stable one, then boutique expensive components shouldn't be necessary to get good performance. Even Marco found his whizz-bang super-duper Croft derived preamp wasn't hugely different from the Series 25 "R" version, which would cost a lot less I believe..

I'm just trying to suggest some simple ways into valves that may stand a fair chance with a modern 4 Ohm speaker and do it right. I don't know the speakers concerned though, but if the amp chosen is the wrong one, then selling on won't be as difficult as it would be with something no-one's ever heard of ;)


Pics courtesy of Walrus..

http://i132.photobucket.com/albums/q8/DSJR_photos/croft_25.jpg

http://i132.photobucket.com/albums/q8/DSJR_photos/croft_Series7.jpg

The Walrus site should show these images more clearly..

[Ali Tait]

I didn't say "can't".My point is that though Croft gear may indeed be excellent,it is nontheless built to a price,as Glen has to make a living.Nowhere did I say though,that Croft gear is poor.As for boutique components,you may in some instances be correct,but in a valve amp transformers are everything,and good tranformers cost a lot of money.

I take your point about selling on,but I was suggesting a way for the OP to get a superb high power SE amp without spending an absolute fortune.I've heard a lot of valve gear over the years,and Nick makes some of the finest sounding amps I've ever heard.

In regard to the impedance issue,theory is all very well,but is no substitute for just trying it!

[Marco]

Even Marco found his whizz-bang super-duper Croft derived preamp wasn't hugely different from the Series 25 "R" version, which would cost a lot less I believe..


That's actually not far from the truth, Dave. My C-X was markedly musically better in any area you care to mention, but not so as to justify the significant difference in cost.

Including the £2k I paid for it (second-hand) as standard originally, and with all the mods since, expensive NOS valves, etc, in total I've spent in the region of £3.2k, so the laws of diminishing returns kick in here as usual.

However if you heard the two side-by-side, and how my C-X handles music in comparison, (if one had the funds) I suspect you'd be whipping out your cheque book for it there and then ;)

In summary, I'd say that my C-X is the sonic equivalent of an £8-10k preamp, using commercial hi-end dealers retail prices as a guide, and the 25R is easily as good as anything up to £5k, using the same pricing guide.

As we say on AOS, that's (non-D.I.Y) SPPV at its best! :cool:

Marco.

[Ali Tait]

I agree, Ali, but my point is that you're not changing the design, as such; it's still Glenn's circuit, so the design stays the same - all one is doing is fitting better quality components of the same value in order to release the full sonic potential of the circuit, and thus hear what it's capable of :)

This is precisely what I've done with my Croft C-X.

I'm totally with you on your last sentence, dude :cool:

Marco.

Yes indeed,but in changing components,you are changing the resulting sound,which is therefore different to the designer's intention.Whether it is better is a subjective matter.

[Marco]

Of course, but who's to know that Glenn wouldn't have used the components I've chosen if he'd had a bigger budget to play with at the start?

Like you say, commercial stuff is built to a price, therefore I'm pretty sure Glenn didn't choose the stock components he did because they were the absolutely best examples on the market for creating the sonic signature he wanted ;)

The improvements I've made are entirely sympathetic to the intrinsic sound of the circuit, dude, I can assure you, as that's the way I wanted it :)

Marco.

[Ali Tait]

I'm not disputing that mate,the point I'm making is that in the original design,components will be chosen to not only keep within the stipulated budget,but to voice the component to the designer's preferences.The point I'm making is that if you change any of the components,the resulting sound will be different to the designer's original intentions.Don't forget that many designs are deliberately made to be not as good as they could be in order not to be serious competition for more expensive kit from the same range.

[anthonyTD]

hi all,
some good points and i agree with most, glenn croft hasnt been around as long as he has by turning out rubbish, far from it, but like most manufacturers in this ever deminishing industry,,, equipment has to be made for a specific price in order to get it out to the most likely of candidates. on the other hand there is no substitute for quality and i am a firm believer that if you make a piece of equipment specificaly for the high end market it has to be of a "no compromise" design from the start! saying that it dosent mean fitting overly priced trinket value components that have little benefit apart from releiving one of their hard earned,,, no, there is a recognised value or price to pay for a realistic and beneficial upgrade in sonics and reliability, and that is what i,,, and i am sure others like glenn are in favour of. as ali has already stated where valve amps are concerned there is no substutute for decent transformers, be it mains or output, these are the heart and soul of any valve amp. some people opt for fitting exotic components in badly designed circuits where their affects do not cure faults but actualy mask them, i for one am not in favour of such things, instead i believe it is esential to get the circuits to work properly in the first place.
A...

[DSJR]

I'm so sorry everyone for stirring up a bit of a hornets nest...

AnthonyTD has it spot on and I suspect the lack of possibly decent transformers at a fair price is the reason why Glenn went to FET's for the output stage, yet kept the valve driver(s). The thing is, IMO Glenn gets the basic design spot on, so that the Marco's of this world (Gawd, are there more than one - :eek:) can fine tune them - not changing the performance overtly, but wringing out more of what is there in the first place..

It's amazing how valvey my own system is quietly becoming at a low price and I'd love a decent STABLE top end valve based power amp. sadly, one of Anthony's or Nicks amps are out of the question as as I'm the permanent custodian of the Quads (long story), I cannot and shall not sell them. the crowns in bridged form aren't so far off the 3-D midband anyway and the bass and treble is better than the Quads anyway..

Apologies to the OP for drifting off as usual.

[Marco]

I'm not disputing that mate,the point I'm making is that in the original design,components will be chosen to not only keep within the stipulated budget,but to voice the component to the designer's preferences.The point I'm making is that if you change any of the components,the resulting sound will be different to the designer's original intentions.


No worries, matey, I get where you're coming from :)


Don't forget that many designs are deliberately made to be not as good as they could be in order not to be serious competition for more expensive kit from the same range.

That would most certainly apply with equipment from other commercial manufacturers, but not from Croft - that's just not Glenn's mentality.

Anthony, spot on, mate!

Marco.

[selfaddict]

I'm not sure how any transformer coupled valve amp will be with 4 Ohm speakers as this technology was designed for 15 Ohm models ideally. Even with 4 Ohm transformer tappings, the amp's output impedance will be rather high and this will have an effect on the speaker crossover points I'm told.


P.S. Garrard 401's go with ANYTHING as long as the plinth is suitable in keeping motor and idler-noise down.

Hello again. Back from work finally :cool:.

I managed to get the impedance graph for Dali Helicon 800's and for my great suprice it is very very good news :):). The impedance stays nearly rock solid on 5 ohm and only peaks to 10 ohm 20 Hz and 65 Hz. So what this means to me is that I can actually "get away" with SET amplifier, can one have better news than that :grouphug:

I need to pop out to take the dogs out, but it seems there has been a lot discussion about this topic, which is only a good thing naturally.

[selfaddict]

What a glorious day it has been, sun is shining and I have a new(second hand) valve amplifier :eyebrows:.

It seems without intended my system is turning little by little more and more British. In the near future next to the wonderful Garrard 401, or actually below it, on the rack will be British made 13wpc SET amplifier. It is going to be zero feedback, pure Class A triode stereo design. It comes with 6ohm output impedance,which could not be better match to my 5 ohm speakers, so the amp will have "room to breathe". It weighs 60 pounds.

This purchase was really not what I was thinking as my introduction to valve amplification, BUT it was too nice amp to let go without giving it a change to show what it is made of. It should work very well with my speakers, at least the specks match good enough for me, but the judgment will be done next week...

[DSJR]

You mean 0.06 Ohm output impedance don't you?????

6 Ohm output impedance will need a 600 Ohm speaker to control it properly I think.....

Put it this way, an output impedance of 0.27 Ohms is enough to alter a typical modern speaker..

See, it's things like this which makes a trial in your own setup essential sadly....

[selfaddict]

You mean 0.06 Ohm output impedance don't you?????

6 Ohm output impedance will need a 600 Ohm speaker to control it properly I think.....

Put it this way, an output impedance of 0.27 Ohms is enough to alter a typical modern speaker..

See, it's things like this which makes a trial in your own setup essential sadly....

Well I am going with the manufacturers specs, which are:

Output Power:13 wpc
Input Sensitivity: 350mV
Input Impedance: 220K ohms
Output Impedance: 6 ohm

[DSJR]

That output impedance is frighteningly high. You MUST try it with no obligation in your own setup..

[Spectral Morn]

What a glorious day it has been, sun is shining and I have a new(second hand) valve amplifier :eyebrows:.

It seems without intended my system is turning little by little more and more British. In the near future next to the wonderful Garrard 401, or actually below it, on the rack will be British made 13wpc SET amplifier. It is going to be zero feedback, pure Class A triode stereo design. It comes with 6ohm output impedance,which could not be better match to my 5 ohm speakers, so the amp will have "room to breathe". It weighs 60 pounds.

This purchase was really not what I was thinking as my introduction to valve amplification, BUT it was too nice amp to let go without giving it a change to show what it is made of. It should work very well with my speakers, at least the specks match good enough for me, but the judgment will be done next week...

Obvious question....What is it ?


Regards D S D L

[selfaddict]

Obvious question....What is it ?


Regards D S D L

That is very obvious question in deed :lol:

It will be Art Audio Diavolo

[Ali Tait]

That's a pretty good amp from what I've read.Certainly a good amp to start with.Enjoy!

[selfaddict]

That's a pretty good amp from what I've read.Certainly a good amp to start with.Enjoy!

I have to admit I went a bit overboard with this, but hei ho, we only live once(I hope ;)) I will send some pictures and first impressions once the gear is in place. Being second hand, there should not be any burn in time required either.

[Ali Tait]

Be interested in how you get on.Pics please!

[Ali Tait]

That output impedance is frighteningly high. You MUST try it with no obligation in your own setup..

I think what he means is that the amp has a 6 ohm speaker tap,rather than 4 or 8 ohm.A lot of manufacturers do that in an attempt to better match modern speakers.I believe the actual output impedance is 200 ohms.

[Ali Tait]

BTW,you are aware this amp uses an output valve that is no longer made and was only ever made by KR Audio? You will be able to source replacements but they may not be cheap.

[Ali Tait]

Upon further reading,this amp was shipped with different output valves.Which does yours have?

[selfaddict]

Upon further reading,this amp was shipped with different output valves.Which does yours have?

Shuguang Black Treasure Valves in situ

Golden Dragon 274b as an spare.

I would be most interested in your input where to start looking for info regarding valves. I am total valve virgin, so I have no understanding what so ever of the subject, but very eager and quick to learn :).

[selfaddict]

I think what he means is that the amp has a 6 ohm speaker tap,rather than 4 or 8 ohm.A lot of manufacturers do that in an attempt to better match modern speakers.I believe the actual output impedance is 200 ohms.

This is what I meant, the amp is designed for 6ohm speaker impedance. This was one of the the main reasons why I went for it, it should work well with my 4-6ohm speakers(as seen from the speaker's impedance graph), but home demo will tell the truth...

[Ali Tait]

Yes that's a common compromise that's made nowadays to allow for the load of modern speakers.Looking on the net it's possible to change this to 4,6,8,and 16 ohms just by resoldering a wire on each output transformer,so good to try with new speakers if you decide to get any.As for the output valves,has this amp been modded? It was my understanding that this amp only worked with the high power 300b krxls from KR or it's original vv32b's or am I wrong?

[Ali Tait]

Regarding valve amps in general,I'm hardly a world's expert,what do you wanna know? The likes of Anthony TD here knows far more than me.

[selfaddict]

Yes that's a common compromise that's made nowadays to allow for the load of modern speakers.Looking on the net it's possible to change this to 4,6,8,and 16 ohms just by resoldering a wire on each output transformer,so good to try with new speakers if you decide to get any.As for the output valves,has this amp been modded? It was my understanding that this amp only worked with the high power 300b krxls from KR or it's original vv32b's or am I wrong?

Hello and many thanks for your advice. As I am a novice with the tube amps I have not asked the right questions obviously :o. Only thing I know that it has been modified by Tom at Art Audio from power amplifier to have volume control and 3 inputs, so I assume the amp can be used as an "integrated" amplifier. This does not really make a big difference to me because it will be solely used with turntable.

Next thing I need to start thinking is what tube phono stage to buy, but this will take some time because it means spending money which I don't have after this transaction :violin:

I attached a picture of the amplifier from the seller. I do not know if that reveals any info about the tubes to anyone???

[Ali Tait]

Those globe 300b's look nice! When are you picking up the amp?

[selfaddict]

Those globe 300b's look nice! When are you picking up the amp?

I am having it delivered early next week. I know it is not ideal, but living in a island in the middle of the Irish sea, only option unfortunately :(

[Ali Tait]

Hope the valves all arrive in one piece!

[selfaddict]

Hope the valves all arrive in one piece!

I had a visit from the courier company. They got it NEARLY right this time, only one box was missing :lol: The problem is that this box contained the amplifier itself. Fingers crossed the amplifier will arrive tomorrow, or latest by Monday.

The tubes that I received today are:

2* Shuguang 300BS
2* Shuguang 300B-Z black treasures
2* Golden Gragon 274B
2* Electro-Harmonix 6922
2* Electro-Harmonix 12BH7

[selfaddict]

The missing box arrived today, which was a nice surprise. Well packed and weight 30kg, so it required couple of deep breaths to get the amplifier safely from the box.

Not long after this it was sitting next to Garrard 401 in a well isolated rack. Then I installed all the 8 valves, speaker cables, interconnects and the power cord and let it settle for few hours before turning it on.

:stalks: Then what happened I am sure people with tube amplifiers can explain to me. There were several sparks inside the left rectifier tube and then nothing. I thought the fuse had gone from the power cord, but no Garrard was working just fine with the same power cord. Then I thought there must be a main fuse inside the unit, so I opened the bottom, but no fuse there.

So has the rectifier tube gone? I would think that the other channel would still work if this is the case?

Any help, please :(

[selfaddict]

Stupid me :doh:, there was a fuse under the power cord after all. It is integrated on the power cord assembly.
Will need T3.15A fuse and I can test the amp on Monday. I think there is an need for new rectifier valves, must have damaged during transport :(.

[DSJR]

Oh the joys of valve amp ownership... :)

I sincerely hope you get yourself up and running on Monday. Watch the affected valve VERY closely when switching on, as it's inadvisable to leave it for hours to "burn in." My Quad's faulty KT66 was fine for ten minutes, but the innards that shouldn't, started to glow red and the distortion quickly mounted. Replacing the valve fixed it completely.

I read on the London Sound forum that any old valve item that hasn't been used for a few years should be turned on for a second, then switched off. next for a couple of seconds and again switched off. next for five and then ten seconds before leaving for half a minute. if it survives this, then it can be left on for the duration - something to do with letting the caps re-form fairly gently and checking the old transformers for shorts etc... This may give Anthony TD a heart-attack, but as my Quads weren't used for over ten years, I thought it advisable to power them up this way. Apart from the valve which failed soon after (it was a used replacement from a few years before - long story) everything is fine.

[alfie2902]

The Art Audio Diavolo is a stunning amp :eyebrows: Such a shame you seem to of had some bad luck with it! I have very little knowledge of valve amps so after changing the rectiflers it would be back to Tom at Art Audio for me.

I suspect I have heard the very Diavolo you own! The mods Tom did to turn it into an integrated version by adding a left & right source selector one each side of the volume control & the 2 extra inputs make me think this must be Robs old one.

Once you get it sorted out I think you're in for a treat! The Diavolo I heard into a pair of Living Voice OBX-RW sounded truely stunning :eyebrows: So much so I nearly bought one myself (perhaps your very one) :)

It's a shame you're so far from Tom here in Notts, He's been really helpful the couple of times I've spoken with him.

Good Luck in sorting it out, it will sound superb!!

[selfaddict]

I suspect I have heard the very Diavolo you own! The mods Tom did to turn it into an integrated version by adding a left & right source selector one each side of the volume control & the 2 extra inputs make me think this must be Robs old one.

Hello.
You are right in deed, it is Rob's old one :). I found this out from another forum after I bought it. But as always in life one mans unluckiness is another mans lucky day,and this time it was my time to be the lucky one.



It's a shame you're so far from Tom here in Notts, He's been really helpful the couple of times I've spoken with him.

This is the drawback living in an island, it is so difficult and costly to get anywhere.I have talked with Tom couple of times about my Diavolo and different valve options I have in the future. I think I am for a treat with this amplifier :eyebrows:. I cannot recommend him enough, very nice person and a true gentleman.

[selfaddict]

I had the fuses delivered today, which was a positive step forward :).

I swapped the rectifier valves from right to left channel, to find out that it is the rectifier which is faulty and turned the amplifier on :stalks:. Same thing happened again, but this time on the left side. Sparks inside the tube and after a two seconds fuse blow again. Well this was something positive :scratch: at least I know that the amplifier should be OK and when I get new rectifiers I should be sorted again :rolleyes:.

Fortunately I had ordered a pair of Golden Dragon 274b rectifier valves this weekend, so if I am lucky I can get a sound from the amplifier by tomorrow, latest Wednesday :eek:.

[selfaddict]

I thought it is time to update what is happening :).

I am in love :champagne:and this one is going to last for a lifetime. I finally found a component in my hifi system that I am certain I do not need to change. Of course there is some tweaking in the future by changing and comparing different valves and combinations, but the Art Audio Diavolo is here to stay :trust:.

I had two sets of rectifiers delivered to me in Wednesday and as I expected they both sets worked without any problems, so the earlier problems were caused by a broken rectifier valve and the amplifier was undamaged.

I have listened my system now two nights, thats 7 hours and I can already say that I am for a treat here. The rectifiers have not even started to burn in and the sound stage is just amazing already. Also the bass has increased expotentially and has tightened considerably. But the biggest difference is with the clarity and resolution of the music, I can hear every string pick up when guitar is played and can determinate all the instruments more clearly. There is more space between instruments. And all this from tuner and cheap CD player. I never thought that I would just play CD after CD and just enjoy the music instead trying to rip it apart wondering what I could improve to make it sound better.

I can say for sure I will NEVER go back to SS amplifiers, I am in audio heaven :harp:

[Jonboy]

I'm pleased for you Juha, another valve convert to the club :)

[alfie2902]

Great news!

Really glad you're enjoying it Juha, It's stunning amp! one of the best I've heard! :eyebrows:

Enjoy the music :)

[selfaddict]

How time flies when you are having a good time. A lot has happened since my last post. I am still enjoying my Diavolo and ever increasing as well I have to admit. I have recently upgraded my rectifiers from Chinese Golden Dragon 274B's to NOS Mullard GZ33 and have ordered few extra pairs of NOS Mullard GZ37's as well for the future. I also changed the power valves from Shuguan 300B-c to Shuguan 300B-z "Black Treasures" and after this the real joy started.

I was a bit disappointed of the slightly bloated low end and thought it must be because of my listening room. Unfortunately I need to keep my Dali's 300mm from the back wall, which is not ideal. But I was more that surprised when I tried the Back Treasure power valves which came as an second pair of power valves with the amp when I bought it. This time I can agree with all the rave reviews what these valves have received. The low end turned very focused and tight and now it is much more in line with the rest of the sound.

So now I have found a lovely combination for the rectifiers (just need to compare the GZ33's to the GZ37's which should arrive soon) and the power valves. I am really happy for the sound as it stands. Of course there is a possibility to fine tune the sound with the pre section valves, but that can wait. I also bought myself a new toy :), a second hand valve tester, which I can use to test and pair valves in the future.

[Ali Tait]

What are the front end valves?

[selfaddict]

What are the front end valves?

Hello.

At the moment they are Russian Electro-Harmonic 6922 (aca.6DJ8 / E88CC) and 12BH7. Tom from Art Audio said that NOS Mullards would be a very good choise, so Mullard E88CC is something I would like to try some stage in the future. For the 12BH7 I think only option is American valves.

[selfaddict]

Hello all and merry Christmas from dull Manx weather :).

Ali could you post me any links regarding changing loading of my Diavolo. I recently bought Bastanis open baffle speakers and would like to change the Diavolo loading to 16 ohm. This will not happen until I have purchased another pair of wideband drivers,which makes the Bastanis truly 16 ohm, but I would like to see if this is a DIY job or do I need to send Diavolo to Tom at Art Audio.

Thanks



Yes that's a common compromise that's made nowadays to allow for the load of modern speakers.Looking on the net it's possible to change this to 4,6,8,and 16 ohms just by resoldering a wire on each output transformer,so good to try with new speakers if you decide to get any.As for the output valves,has this amp been modded? It was my understanding that this amp only worked with the high power 300b krxls from KR or it's original vv32b's or am I wrong?

[Ali Tait]

Hi Juha,

Can't find any at the moment I'm afraid,and I can't find the site that said there was a 16 ohm tapping on the output transformers. It may be there isn't one. Might be best to ask art audio before proceeding,though if you are happy to have a look inside yourself it should be straightforward to change,as long as you are well aware of the dangerous voltages inside the amp! Power supply caps in particular can keep their charge for weeks or even months,so bear that in mind if you have a look inside.

If the amp is anything like the WAD 300b PP I used to have,there will be several tags or wires coming from the output transformers,only one of each will go to the speaker terminals inside the amp. The tappings should have their value written on the transformers,next to each respective tag or wire. Assuming this,it's a simple matter of desoldering the 8 ohm wires from the back of the speaker terminals (assuming it's wired for 8 ohms at the moment) and reoldering the wires from the 16 ohm tappings to the speaker terminals,or if it's just tags at the transformers, desolder the wires from the 8 ohm tag on each output transformer, and resolder to the 16 ohm tag if there is one.

If you are unsure about this, you could post some pics of the innards and we could take it from there.

Only attempt this if you are confident you can keep yourself safe from the dangerous bits inside! A good rule of thumb is only to have one hand inside the amp at a time,and keep the other well away. This would prevent any shock from passing across your chest with possible dire consequences. Sorry to sound alarmist,but high voltages are looking for you,and want to kill you!

I'll keep looking and see if I can find the site for you.

[selfaddict]

Hello Ali and many thanks again for your help :respect:

I took the bottom plate off from the amp and it seems that there are two sets of wires coming from each of the transformer, one pair of yellow and one pair of grey per channel. Without taking the transformers out from the above, I cannot see if there are any additional tappings on the transformers.

[PRYML]

Sorry to sound alarmist,but high voltages are looking for you,and want to kill you!

I know it's no joking matter, but that little statement cracked me up with much needed spontaneous laughter :lol:

[selfaddict]

It definitely is not joking matter. Many years ago I treated a electrician who had rushed in his work and because of this we had to amputate his right upper limb including his shoulder plate. He was 'lucky' that the electricity had not gone through his heart, instead electricity burned itself through his body and came out left side of his rig cage. Not a pretty site I can tell you that.

I know one does not have same current/voltage on home environment, but since then I have been extra carefully what I do and don't do when it comes with electricity and hope everyone will do as well.


I know it's no joking matter, but that little statement cracked me up with much needed spontaneous laughter :lol:

[PRYML]

Oooo... you do paint a ghastly picture, Juha :doh:

[Reid Malenfant]

I know one does not have same current/voltage on home environment, but since then I have been extra carefully what I do and don't do when it comes with electricity and hope everyone will do as well.
Very sensible to ;) I just had to check that one of my multimeters wasn't malfunctioning or the battery wasn't low before i just tackled my central heating pump not running :doh: All good now though :)

If in any doubt at all:- Check, check & check again before dealing with mains voltages!

[Ali Tait]

It definitely is not joking matter. Many years ago I treated a electrician who had rushed in his work and because of this we had to amputate his right upper limb including his shoulder plate. He was 'lucky' that the electricity had not gone through his heart, instead electricity burned itself through his body and came out left side of his rig cage. Not a pretty site I can tell you that.

I know one does not have same current/voltage on home environment, but since then I have been extra carefully what I do and don't do when it comes with electricity and hope everyone will do as well.

I can see how it may be amusing, but in the 20+ years I've worked in the high voltage industry, I've been to seven funereals of workmates, the last being someone I'd known for most of those years. He was only 40, and left a wife and four young children. I really don't want to go through that again,or see others go through it, so please folks, BE CAREFUL!

[Ali Tait]

Hello Ali and many thanks again for your help :respect:

I took the bottom plate off from the amp and it seems that there are two sets of wires coming from each of the transformer, one pair of yellow and one pair of grey per channel. Without taking the transformers out from the above, I cannot see if there are any additional tappings on the transformers.

Hi Juha, it may be the trannies only have two tappings-4 and 8 ohms, or 6 nominal is it? There may be more tags on the trannies,but best to ask Art Audio first, as it looks like you'd need to remove the PCB's to get at them. Sorry I can't be more help, I've never seen or heard one of these amps before.

[Ali Tait]

Actually,looking at the picture, it wouldn't be too difficult to undo the fixing nuts holding the PCB's and lift them up for a look if you fancy having a go.

[Reid Malenfant]

Interesting that there are what appears to be possibly two secondary windings on each channel. Two Grey & two Yellow leads from each transformer suggests two starts & two finishes.

From what i can see they look to be in parallel right now as both yellows & both greys are joined together. It may well be that to get the loading you are looking for you'll need to wire them in series ;)

Like Ali says, check up with Art Audio & find out, you may be pleasantly surprised :)

[Ali Tait]

Yes, you may well be right there Mark. If there are two secondary windings,it may depend on how they are wired up.