View Full Version : All this talk of head amps got me looking......
PaulStewart
17-11-2013, 16:06
With all this talk of head amp bringing back memories, I've just bought THIS (http://www.ebay.co.uk/itm/251378294011?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649) on fleabay. At under 70 squids it's got to be worth a play :) I don't remember them well, but don't recall any nasty tales about them.
On the main system I use the phone stage in the Art Audio VPS with a matching transformer, I'll give this device a listen when I get it and report back. I think I might have to mod it for loading, but thats not the end of the world. The seller made an error and listed in as being for MM carts. which may explain the low price. Fair play to the chap he did mail me and point out the error after I had won it, so I presume he would have let me cancel if I'd wanted to. Can't wait to have a play.
Cheers all
Ali Tait
17-11-2013, 16:12
Interesting. Might be quite good?
The Barbarian
17-11-2013, 16:15
I remember the Grant amps coming out,nice with moggy side cheeks.. i'll admit i did fancy one..
Arkless Electronics
17-11-2013, 16:21
I predict noise problems.... lots of them if it is indeed an all valve head amp! Apparently that model you have is rare as rocking horse droppings so a good find anyway!
Noise won't be as good as SS or a step up, but a pair of 88's as a MC front end can sound very good. Depends on your cartridge, but noise should be below the vinyl background level with a 300uv or so cartridge. Picking the right ECC88 will go a long way towards getting the noise as low as possible.
Arkless Electronics
17-11-2013, 16:45
Noise won't be as good as SS or a step up, but a pair of 88's as a MC front end can sound very good. Depends on your cartridge, but noise should be below the vinyl background level with a 300uv or so cartridge. Picking the right ECC88 will go a long way towards getting the noise as low as possible.
They can certainly sound very good, that's not the issue. I have a valve head amp here of my own design which uses 4 x ECC88, to give theoretically 3dB less noise than 2 x ECC88. The noise is adequately low in practice for me but I suspect many people would, if they compared it to a SUT or SS head amp, comment on it being "a bit noisy". I didn't find it a problem in practice, as you say once the arm is lowered the vinyl noise is far greater. However, even Mullard E88CC's were only just good enough and I had to change valves with alarming regularity. Valves which were fine for ANY other application were still too noisy for this and any good set would have one go a bit noisy before long (usually rustling or crackling sounds rather than hiss). It's the head amp equivalent to owning and using a vintage sports car I suppose.... temperamental and expensive to run!
The Barbarian
17-11-2013, 16:47
Well at least he got a bargin with the postage
:wave:
They can certainly sound very good, that's not the issue
Well, if I read the original posters intention, its very much the issue. Its just a play for <£70. I agree they can sound very very good, I found the best was a ultra high gm pentode E810F, but thats an insane valve (it will oscillate in it box :-)) and they are getting expensive. It was the sound of that pentode front end that took me to the jfet front on a valve phono stage.
Arkless Electronics
17-11-2013, 18:34
Well, if I read the original posters intention, its very much the issue. Its just a play for <£70. I agree they can sound very very good, I found the best was a ultra high gm pentode E810F, but thats an insane valve (it will oscillate in it box :-)) and they are getting expensive. It was the sound of that pentode front end that took me to the jfet front on a valve phono stage.
I looked at that valve myself.... and some even higher transconductance ones that exist! Silly money and like you say a bit tetchy when it comes to oscillating!
Agreed it's a steal at £70 as something to have a play with though :)
I use JFET's in some of mine (the new head amp included) and also have JFET/valve hybrid designs.... it's not the designing them that's the problem... it's the marketing etc! :eek: Is this your experience as well Nick?
I built a MC preamp some time ago using matched pairs of Mullard E88CC valves with DC heater supply. Beautiful liquid midrange, but obviously noisier than SUTs and SS preamps. In the end I replaced it with various SS devices.
Perhaps I should dig it out and see if it could be improved?
Arkless Electronics
18-11-2013, 00:18
I built a MC preamp some time ago using matched pairs of Mullard E88CC valves with DC heater supply. Beautiful liquid midrange, but obviously noisier than SUTs and SS preamps. In the end I replaced it with various SS devices.
Perhaps I should dig it out and see if it could be improved?
Why not... I may even dig out mine and update it a bit! I may have problems with finding enough valves that are quiet enough now though :rolleyes:
belloire
18-11-2013, 10:25
the phono stage in my AI S200 pre is all valve. uses 2 x ecc83 + 1 x ecc82 for the mm stage, and a further ecc83 for the mc. (is 88 the norm for this? or does 2 x 88 = 1 x 83?)
it is a bit noisy, but it's also seen of some very good competition.... i have a nice SUT to try with the mm stage now too, so i'll see how that goes
Arkless Electronics
18-11-2013, 11:12
the phono stage in my AI S200 pre is all valve. uses 2 x ecc83 + 1 x ecc82 for the mm stage, and a further ecc83 for the mc. (is 88 the norm for this? or does 2 x 88 = 1 x 83?)
it is a bit noisy, but it's also seen of some very good competition.... i have a nice SUT to try with the mm stage now too, so i'll see how that goes
An ECC83 is not a good idea for a head amp! It's far too noisy and has characteristics that just don't suit using it in such a way..... Are you sure there's no SUT? I'm certainly not saying it wouldn't work, just it would likely be very noisy even by valve head amp standards...
The ECC88 (6DJ8, 6922, E88CC) is by far the most popular valve for head amps. There are even better valves than the ECC88 but non that aren't very expensive and difficult to obtain.
belloire
18-11-2013, 12:24
we thought the same, but can't see any transformers. it's most odd, and though it's a bit noisy, it's really good. i'm going to look for a low microphony 83 to replace the one that's in there, see if it makes a difference.
An ECC83 is not a good idea for a head amp! It's far too noisy and has characteristics that just don't suit using it in such a way.....
Am I understanding this wrongly, Jez? Isn't Darren saying that he uses ECC83s (together with 82s) in his phono stage, not his head amp? Certainly, that's what he appears to be saying here:
the phono stage in my AI S200 pre is all valve. uses 2 x ecc83 + 1 x ecc82 for the mm stage, and a further ecc83 for the mc.
:scratch:
Marco.
Arkless Electronics
18-11-2013, 14:17
Am I understanding this wrongly, Jez? Isn't Darren saying that he uses ECC83s (together with 82s) in his phono stage, not his head amp? Certainly, that's what he appears to be saying here:
:scratch:
Marco.
It seems to me that what is being described is an all valve phono stage with an internal MC head amp using ECC83's rather than an internal SUT... unless it's me that's misunderstanding it!? Maybe if Darren can be bothered to post some close up pics of the circuitry we can get to the bottom of this.. A ECC83 is a VERY bad choice for a MC head amp :eek: To the point that I'd be surprised if there is not more to the story here ;)
Yes, it's all rather confusing... ECC83s would indeed be a brutal choice of valve for a head amp, but not a phono stage. The two are separate entities - or not, in Darren's case!
Tune into next week's episode where all will be revealed.... :eyebrows:
Marco.
belloire
18-11-2013, 15:39
rather than not being bothered, i don't presently have a pic of the stage internals (if i can be bothered seems a little harsh, i only offered information!)
there are 2 versions of the S200, 1 with MM only, 1 with MC. the difference is the extra ecc83 and some bits, but the step up is all valve (i'm told).
i don't know anything about electronics in reality, but i do know the phono stage is very good, punching way beyond the £250 i paid for it as a passive preamp with a phono stage built in.
Arkless Electronics
18-11-2013, 15:48
rather than not being bothered, i don't presently have a pic of the stage internals (if i can be bothered seems a little harsh, i only offered information!)
there are 2 versions of the S200, 1 with MM only, 1 with MC. the difference is the extra ecc83 and some bits, but the step up is all valve (i'm told).
i don't know anything about electronics in reality, but i do know the phono stage is very good, punching way beyond the £250 i paid for it as a passive preamp with a phono stage built in.
No offence intended! :) All I meant by it was that I would perfectly understand someone not wanting to go to the trouble of removing it from their system, taking the lid off and then taking photos and posting them on here all just for the sake of our curiosity! :)
PaulStewart
19-11-2013, 23:11
Well It's arrived thanks to the wonders of Parcel Force who combined with PayPay crashing when I tried to select another delivery address, delivered it to my office (no one was there, we were out on assignments) It should have gone to our warehouse, where of course there were people to sign for it. However, it's at home the Mrs. has unpacked it, plugged it in and switched on the Stax energiser, so it will be ready for me to wire up and have a listen to, when I get this paper to bed and go home around 2:00am :( However I can't wait :) really intrigued with this one.
Cheers all
PaulStewart
20-11-2013, 02:49
Right it's here and a bit noisy/crackly there a 4 valves in there not two, I'll open it up tomorrow and get some new ones. On first listen albeit through cans, it has a huge soundstage and without overemphasising anything, it has one of the most fluid, lucid mid bands I've ever heard. Brass and strings have tremendous texture, drums are properly percussive. I'll report more once I've sorted it.
PaulStewart
21-11-2013, 01:00
Right I've now had a chance to open it up and have a look inside..... And it has FOUR ECC88s and a transistor per channel. I can't see what they are yet as I was using an inspection mirror, the valves are 20 year old Brimars so I'll get some good ones ordered ASAP.
Sound wise it is an amazing bit of kit, vast soundstage, extremely fluid and lucid mid band with an amazing amount of detail. Great bass, treble and dynamics the noise floor is higher than the pre with an SUT but it's well below the level of the vinyl and it even came with the original box :)
Arkless Electronics
21-11-2013, 02:27
Right I've now had a chance to open it up and have a look inside..... And it has FOUR ECC88s and a transistor per channel. I can't see what they are yet as I was using an inspection mirror, the valves are 20 year old Brimars so I'll get some good ones ordered ASAP.
Sound wise it is an amazing bit of kit, vast soundstage, extremely fluid and lucid mid band with an amazing amount of detail. Great bass, treble and dynamics the noise floor is higher than the pre with an SUT but it's well below the level of the vinyl and it even came with the original box :)
Four per channel!!? That can't of been cheap when new !
Firebottle
21-11-2013, 08:04
I think he meant 4 ECC88s in total plus a single transistor in each channel :doh:
Would be interesting to know what sort of current level the ECC88s work at :hmm:
:cool: Alan
PaulStewart
21-11-2013, 11:01
It's as Alan says two bottles and a tranny per channel, just ordering the new valves now, going the NOS route. Mullard or Tungsram seems to be the question.
Ali Tait
21-11-2013, 11:04
Amperex are nice too IMHO.
Arkless Electronics
21-11-2013, 12:14
I think he meant 4 ECC88s in total plus a single transistor in each channel :doh:
Would be interesting to know what sort of current level the ECC88s work at :hmm:
:cool: Alan
Usually in this type of application around 10 - 15mA per triode ;)
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