Amity Horror becomes Amity V2 becomes …

What people are working on at the moment
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Dave the bass
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#31

Post by Dave the bass »

andrew Ivimey wrote:
Phroaaaaaaar! to paraphrase another member.
Oi! You missed out 7 'W's after the 'ph' and that 'r' goes at the end.

Pay attention :D

DTB

PS. Well done on attained a state of sonic nirvana banana.
"The fat bourgeois and his doppelganger"
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andrew Ivimey
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#32

Post by andrew Ivimey »

Mark's comment is right though - let's see after two weeks.

But, assuming I am now in the right playing field,ball park or what, Amity is pretty good and I can tweak to finish the amp off as the preamp (as low impedance wire with gain) can now be a constant.

Right now 'Mysterious Traveller' is sounding particularly nice - great dynamic range too with lots of lovely percussive tinkly bits that ribbons do so well.
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andrew Ivimey
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#33

Post by andrew Ivimey »

Two weeks or so have gone by.

I was able to try the amp out with massive tannoy speakers / schroeder arm etc etc etc (i.e. a superb system).

Not bad at all! amazing clarity and detail, 'speed' wow! not perfect but hugely impressive - best amp yet? perhaps. (Ongaku is different and on a plinth of its own, too) but Amity is seriously making me consider why bother with all/any of the others?)

I have been worrying about that oh so critical ultrapath cap on the driver stage. Could I afford 10mfd PIO Audionote? Had I the space?!

First things first, the driver stage now has no ultrapath cap. It sounds very good indeed. I believe there is a small tonal diffference, but I am not sure. I will try to rig up a switched system for trying several possibilities but ultrapathschmultrapath - who needs'em?
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#34

Post by Cressy Snr »

Calm down Andrew, calm down :D

Seriously: glad to hear you are getting there with the amp.
I have tried ultrapath too in my PP amp driver stage and can't make up my mind. One day I like it, the next I'm not so sure. I finished up taking it out and TBH I haven't missed it.

Steve.
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IslandPink
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#35

Post by IslandPink »

Hello Andrew
Looks like it's going pretty good then ?
I suppose one advantage of the ultrapath cap is you can use something better quality than the main PS caps, but if you don't, the effect of ultrapath may be marginal .
How high is your B+ ?
If it's less than 350, you might want to try a Black Gate VK 22u / 350v which are very nice indeed - I use them as the critical decoupling cap for stage 1 in my phono .

ILPS
"Once you find out ... the Circumstances ; then you can go out"
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andrew Ivimey
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#36

Post by andrew Ivimey »

I'm mussing along at around 315 volts, depending on how I'm feeding the HT into the amp.

VKs are polarised aren't they? I have never thought that I could use polarised caps for ultrapath.

I am looking forward to some sustained time to try and play and test. At present the amp looks like a dog's breakfast - so depressing. Build 3 is essential but won't get built till long after e.g. Owston.
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Nick
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#37

Post by Nick »

VKs are polarised aren't they? I have never thought that I could use polarised caps for ultrapath.
Can't think of any reason why not, the cathode will never be higher in potential than B+
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andrew Ivimey
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#38

Post by andrew Ivimey »

True, but all ultrapaths I have seen have not been using electrolytics so I blithely assumed non polarity as being right..

p s. why do they all go on and on about PIO for ultrapaths then? (smaller values need only apply whereas in this design I think in one version it used 80mfd. - and that is the driver stage not the output stage.)
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Nick
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#39

Post by Nick »

Well, avoiding the what sounds best argument, I guess it comes from the fact when the circuit was originally presented, that was about all that was available at the required voltage (maybe).
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#40

Post by IslandPink »

No, I don't think so, I guess the idea was to use something better than an electrolytic - LynnO used the best he could think of for that size, which was GE polyprop/oil with a teflon by-pass . Those are jolly good actually .

There would be a problem using any electros or Black Gates in that circuit because Lynn was pushing 500V and now uses over 500V for the output stage .
I used a smaller KP-SN for the driver stage on mine .

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andrew Ivimey
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#41

Post by andrew Ivimey »

Well, touch wood the CCS issues seems to be fixed; 65volts across them and all seems well.

Now back to the ultrapath .... that one component should make such a difference ... right now I am using 30mfd film in oil obligatto and teflon 0.056. I think it sounds fine but tomorrow I get a chance to try the amp with rather large Tannoys.

Then a rebuild to tidy thigs up....

or is that a Raven-like pre-amp I feel should be done. Some sort of pre-amp is necessary and an AVI one, although very reassuring to have around, just isn't de-rigeur!

I connected up my 2A3 baby ongaku yesterday and immediately I heard 'SE' - all very nice but very confusing to my ears that have accustomed to Amity.

And I have lost any objectivity I once may have had about the quality of Amity, but it does still draw me in to careful listening.

Others need to hear it and you can be harsh (or not) with me! :wink:
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#42

Post by Cressy Snr »

Hi Andrew

It's the same with the PP 6AS7 It does things that SE can't do but one day I like it the next I like the SE amp. I can't really be objective about it. I suspect the driver stages in my PP amp need beefing up a bit in terms of current drive to the outputs. I think I have taken it a bit too low, losing a bit of the dynamics, in an effort to make it be all things to all men. This is why it is currently in bits while I sort out the drivers.

I have given the SE a good workout this morning with the 2007 Simon Rattle Mahler 9 with the BPO. All I can say is 2 Watts goes a long way, especially when the low end is handed off to a pair of 100 Watt subwoofers! I still daren't play the Mahler 8 though :shock:

Mahler on the Amity through those Tannoys will blow your socks off. If you like that sort of thing, that is. :D

Steve
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andrew Ivimey
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#43

Post by andrew Ivimey »

I do indeed like that sort of thing Steve. Last time Amity met Tannoys we started with Mozart flutes to Frankie Goes to Hollywood and then some techno - disco rubbish to test the low frequency response; synthesised bass really does go atrociously low, (but you need a speedy resonse or you miss teh attack transient to mush) a touch of Nirvana and the rest of the night was given over to serious Shostakovich. Mahler 8 might get taken to a desert island but I actually prefer Mahler 9 when there is choice.

I caught myself thinking as I was cycling home just now that weedy SEs just can't cut it with complex music. I was just thinking ......


ducks ....
:wink:
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#44

Post by Cressy Snr »

andrew Ivimey wrote:I
I caught myself thinking as I was cycling home just now that weedy SEs just can't cut it with complex music. I was just thinking ......


ducks ....
:wink:
You'll be turning into Greg if you're not careful Andrew :D

Seriously though the SE managed very well with the Mahler. It thickened up only once during the last movement for about 1 second where a trumpet blast combines with a sudden spurt of violas plus an almighty whack on a timpani. You could hear the brass duck in volume as something or other ran out of steam. Could have been the speakers with their tiny drivers compressing but I'm inclined to blame the amp there.

This is however in a very small 12x12 room. I wouldn't dream of asking it to do Mahler at Owsfest unless I wanted egg all over my face.

Steve
Last edited by Cressy Snr on Thu Apr 03, 2008 3:25 pm, edited 2 times in total.
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pre65
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#45

Post by pre65 »

There might be enough of us PP lovers soon to fight off the SE brigade !! :wink:
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