Px 25 again

What people are working on at the moment
Post Reply
steve s
Shed dweller
Posts: 2829
Joined: Wed May 30, 2007 6:19 pm
Location: east yorks

#1 Px 25 again

Post by steve s »

Well after a short life as a small intergrated amp the latest px 25 build is now a double decker

What may look like a nice plinth houses 4 x power supplies, all cap input due to the fact this was more of a trial, and i used pairs of transformers i had.

Just got it together in the case tonight, so it will take a few days of running in and checking out.

Its very dynamic and realistic sounding, very similar to what you heard at the last meet, probably even more so, the real benifit is when playing complicated pieces when the seperation is so much better than my prevous efforts, the sound is cleaner yet i would say more detailed with the sublties coming more forward.
Thanks to dave and thomas for the inspiration...

The voltages are not quite where i would like them to be on the driver valves, i could have done with another 20 volts or so, ...so its not quite finished, but it will have to do for the wigwam show in 2 weeks.. Anybody going.. I have a big room so it could be a good meeting point?

Before then I now have the speakers to modify, the bass baffles need some work with some heavy damping required on the lines of my smaller speakers and the beyma's need mounting properly and the side cheeks removing from when the vitavoxs where installed.
A couple more weeks of stress...
Attachments
image.jpg
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
steve s
Shed dweller
Posts: 2829
Joined: Wed May 30, 2007 6:19 pm
Location: east yorks

#2

Post by steve s »

Another picture but this time in the nude.. Before i started tarting her up for installing in the box..
Attachments
image.jpg
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8879
Joined: Mon May 21, 2007 9:42 pm

#3

Post by Paul Barker »

That's a handy construction method, to make them in a skeleton, test them, and then drop a presentation case over the top.

Regarding the multiple power supplies. You guys have lifted the bar beyond the length of my arms.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8879
Joined: Mon May 21, 2007 9:42 pm

#4 Re: Px 25 again

Post by Paul Barker »

steve s wrote: the wigwam show in 2 weeks.. Anybody going.. I have a big room so it could be a good meeting point?
I have a Nephew wedding in Brighton.

Are you having a room to sell something or is it just what you have to do to demonstrate your stuff? Presumably it is considerable cost when it is as much as £12 just to walk in the door with nothing but the clothes you are wearing?
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
steve s
Shed dweller
Posts: 2829
Joined: Wed May 30, 2007 6:19 pm
Location: east yorks

#5 Re: Px 25 again

Post by steve s »

Paul Barker wrote:
steve s wrote: the wigwam show in 2 weeks.. Anybody going.. I have a big room so it could be a good meeting point?
I have a Nephew wedding in Brighton.

Are you having a room to sell something or is it just what you have to do to demonstrate your stuff? Presumably it is considerable cost when it is as much as £12 just to walk in the door with nothing but the clothes you are wearing?
You are right its about £12 but you save a couple by prebookingto get in, but there are around 50 rooms with all sorts of equipment combos, and a few other rooms with some good diy gear,
Its a good day out, some of the rooms are smaller bedrooms and are full with 8 visitors, this year i would be able to get 30-40 in the room. So consider myself very lucky
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
Cressy Snr
Amstrad Tower of Power
Posts: 10552
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

#6

Post by Cressy Snr »

A great amp Steve :D

Looks good as always. Looking forward to a listen.
How about when I visit, I bring my pp amp?

No doubt i'll go home a broken man. but will have learned something from the experience.
Sgt. Baker started talkin’ with a Bullhorn in his hand.
User avatar
thomas
Old Hand
Posts: 910
Joined: Sat Sep 26, 2009 1:52 am
Location: N.W.Kent

#7

Post by thomas »

Yep, looks great, and bijou too :D
steve s
Shed dweller
Posts: 2829
Joined: Wed May 30, 2007 6:19 pm
Location: east yorks

#8

Post by steve s »

Thanks all for the nice comments, i left it playing all day whilst i was working, i could hear a slight distortion every once in a while, so checked it out tonight , had to reset the driver auto bias as there was not quite enough current for the interstage, should have checked it properly as i knew the ht was lower than i'd hoped.
I can already feel a mark 2 coming up.. I know it should be choke input, and needs more voltage.

More than welcome to bring your push pull amp Steve, we will have to sort a date.
Cheers..
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8879
Joined: Mon May 21, 2007 9:42 pm

#9

Post by Paul Barker »

Yes Steve my first time hearing both valves. Nothing has changed, haven't heard a Chinese 845 worth the pain of building an amp for yet. But I haven't heard a psvane. Maybe they are made to closer tolerances. The issue was always the rattling of the anode against the support rods. Just shoddy workmanship came through in the sound.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8879
Joined: Mon May 21, 2007 9:42 pm

#10

Post by Paul Barker »

I may have put that in wrong thread. Ho hum.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
Deco-Doctor
User
Posts: 177
Joined: Sun Oct 28, 2007 8:58 am

#11 Re: Px 25 again

Post by Deco-Doctor »

steve s wrote:but it will have to do for the wigwam show in 2 weeks.. Anybody going.. I have a big room so it could be a good meeting point?
:hello2:
steve s
Shed dweller
Posts: 2829
Joined: Wed May 30, 2007 6:19 pm
Location: east yorks

#12 Re: Px 25 again

Post by steve s »

Deco-Doctor wrote:
steve s wrote:but it will have to do for the wigwam show in 2 weeks.. Anybody going.. I have a big room so it could be a good meeting point?
:hello2:
Be nice to see you Martin, there looks to be a few of us there, im steve 57 on the guide.
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
Post Reply