Poundland 45

What people are working on at the moment
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8882
Joined: Mon May 21, 2007 9:42 pm

#31 Re: Poundland 45

Post by Paul Barker »

OK, Ive been watching a load of nice SE amps on youtube and their iron is mounted like yours so the flux merging doesnt apparently matter.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
Cressy Snr
Amstrad Tower of Power
Posts: 10552
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

#32 Re: Poundland 45

Post by Cressy Snr »

Paul Barker wrote: Sun Jul 04, 2021 11:28 pm OK, Ive been watching a load of nice SE amps on youtube and their iron is mounted like yours so the flux merging doesnt apparently matter.
Hi Paul,
Which set of transformers are you objecting to?
Is it the output transformers next to each other, or is it the mains transformers in the screened box at the back being near to the output transformers. The choke is also screened, but as part of a pi filter, I can’t see it radiating much of an electric field: certainly not to the extent it would if it were part of a choke input supply.

Or is it just that the whole kit and caboodle is so filled with compromises for the sake of aesthetics that it is frankly an insult to the 45 valve?
Sgt. Baker started talkin’ with a Bullhorn in his hand.
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8882
Joined: Mon May 21, 2007 9:42 pm

#33 Re: Poundland 45

Post by Paul Barker »

we just have a different perspective, my amps and speakers look crap. If transformers sat bang next to each other works for you and others and ive been wrong all along to space mine out it doesnt matter. Im happy.
Last edited by Paul Barker on Mon Jul 05, 2021 12:10 pm, edited 1 time in total.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
Cressy Snr
Amstrad Tower of Power
Posts: 10552
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

#34 Re: Poundland 45

Post by Cressy Snr »

OK,
Got the baseboard and the feet on:
C3D9347A-88A0-45DC-AA54-902FE4A4C1F1.jpeg
C3D9347A-88A0-45DC-AA54-902FE4A4C1F1.jpeg (88.66 KiB) Viewed 2602 times
FE60843F-497B-4EE3-88A8-7B96F4DED2C3.jpeg
FE60843F-497B-4EE3-88A8-7B96F4DED2C3.jpeg (80.91 KiB) Viewed 2602 times
And before anybody starts: yes I know one of the speaker terminal’s fixing holes has drifted off. I call these things lovable quirks these days, rather, than using them as an excuse to get all OCD about them.
Sgt. Baker started talkin’ with a Bullhorn in his hand.
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8882
Joined: Mon May 21, 2007 9:42 pm

#35 Re: Poundland 45

Post by Paul Barker »

it is beautiful. And it sounds far better than it looks.And I musnt start a sentense with And.
"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: 8882
Joined: Mon May 21, 2007 9:42 pm

#36 Re: Poundland 45

Post by Paul Barker »

Ive been listening to this guys amps, theyre all squashed together like your new iteration, so I must have been wrong all these years. but im not changing, for me if theres a possible route for cross talk and mysterious hum I close it with spacing my iron whether potted or not.

Image
honda crz 0 60
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
Cressy Snr
Amstrad Tower of Power
Posts: 10552
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

#37 Re: Poundland 45

Post by Cressy Snr »

Didn’t really like the large feet: too flash and they competed for attention, causing my eyes to be constantly flipping between feet and main body of the amp. I replaced them with simple rubber feet: much better. :)
F182D544-4834-433D-96E1-A2B44E2DA3DF.jpeg
F182D544-4834-433D-96E1-A2B44E2DA3DF.jpeg (87.54 KiB) Viewed 2580 times
Sgt. Baker started talkin’ with a Bullhorn in his hand.
User avatar
IslandPink
Amstrad Tower of Power
Posts: 10041
Joined: Tue May 29, 2007 7:01 pm
Location: Denbigh, N.Wales

#38 Re: Poundland 45

Post by IslandPink »

The little feets will not fail you now !
"Once you find out ... the Circumstances ; then you can go out"
Cressy Snr
Amstrad Tower of Power
Posts: 10552
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

#39 Re: Poundland 45

Post by Cressy Snr »

IslandPink wrote: Mon Jul 05, 2021 4:14 pm The little feets will not fail you now !
ISWYDT.
Sgt. Baker started talkin’ with a Bullhorn in his hand.
User avatar
Ray P
No idea why I do this anymore
Posts: 6294
Joined: Thu Nov 22, 2007 5:18 pm
Location: Somerset

#40 Re: Poundland 45

Post by Ray P »

I like it Steve - do you have that proud father feeling?
Sorry, I couldn't resist!
Cressy Snr
Amstrad Tower of Power
Posts: 10552
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

#41 Re: Poundland 45

Post by Cressy Snr »

Ray P wrote: Mon Jul 05, 2021 7:36 pm I like it Steve - do you have that proud father feeling?
Yep,
It has turned out well beyond what I expected, both in terms of looks and sound quality.
Last edited by Cressy Snr on Mon Jul 05, 2021 8:01 pm, edited 1 time in total.
Sgt. Baker started talkin’ with a Bullhorn in his hand.
Cressy Snr
Amstrad Tower of Power
Posts: 10552
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

#42 Re: Poundland 45

Post by Cressy Snr »

OK, so I've now got the proper 5R4GY rectifier installed.
IMG_0739.jpeg
IMG_0739.jpeg (51.29 KiB) Viewed 2526 times
Revised schematics below:

Kiwame resistors now load the anodes of the ECC88 and I got a nice 25K Allen Bradley dual gang volume pot off our Ant. In exchange I gave him a couple of 100K mono TOCOS pots.
Screenshot 2021-07-05 at 19.45.37.png
Screenshot 2021-07-05 at 19.45.37.png (90.48 KiB) Viewed 2526 times


Power supply is set up to treat the 45s nice and gentle.
Screenshot 2021-07-05 at 19.36.13.png
Screenshot 2021-07-05 at 19.36.13.png (89.72 KiB) Viewed 2526 times
Sgt. Baker started talkin’ with a Bullhorn in his hand.
Cressy Snr
Amstrad Tower of Power
Posts: 10552
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

#43 Re: Poundland 45

Post by Cressy Snr »

Cressy Snr wrote: Sun Jul 04, 2021 10:22 pm
… the physical layout of the two 45s and the single ECC88 driver stage, means it is completely impossible to mess with; there simply isn’t the room. I took a conscious decision with this amp to deliberately make it difficult, if not impossible to modify. There can be no alternative drivers apart from those in the ECC88 family. There can be no octal driver substitutions, no room. There can be no DC modules for the 45 filaments, no room. No HT regulators: solid state or otherwise, no room. No fancy stepped attenuator, no room. The amp is basic, is what it is and is forced by its small size to remain so, which is good.
Well I didn’t bargain for the scope that a 5V rectifier on an octal socket scheme would give for endless plugging and unplugging. :banghead:
Anyway I’ve taken the initiative, and shut down that particular avenue good and proper, with the aid of a B5 socket and 0.47R power resistor to give near as dammit a 4V/2A rectifier spec.
The 4V transformer I have is too big to fit, which is actually a good thing, because the 0R47 resistor means only 4V/2A spec unless the resistor is changed. The resulting inconvenience stops any chance of me even thinking about Mullard FW4-500s and their 3A ilk.
My sole Mazda UU4 is now in residence in the rectifier position. It is the only 4V, full wave rectifier valve I have. Fecking about is now shut down on all fronts.
04E58C5A-1B43-4DA0-A1BE-3C93B69F89BE.jpeg
04E58C5A-1B43-4DA0-A1BE-3C93B69F89BE.jpeg (90.13 KiB) Viewed 2447 times
Peace. Perfect peace. :flower: :flower:
Sgt. Baker started talkin’ with a Bullhorn in his hand.
User avatar
andrew Ivimey
Social Sevices have been notified
Posts: 8307
Joined: Mon Jun 11, 2007 8:33 am
Location: Bedford

#44 Re: Poundland 45

Post by andrew Ivimey »

Oh you'll find a way! Onwards...
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.
Cressy Snr
Amstrad Tower of Power
Posts: 10552
Joined: Wed May 30, 2007 12:25 am
Location: South Yorks.

#45 Re: Poundland 45

Post by Cressy Snr »

Have finally got it finished properly. A baseplate has been fitted, made of 1mm perforated steel. This is earthed via a copper strip from the chassis safety ground. Contact is made to the strip when the plate is screwed to the wood frame, so that the base can be removed without having to deal with an earth wire.
Everything has been filed and rounded over to remove any sharp edges, so it is not as hand shredding, on two of the edges as it looks. :)
86F97CB2-49EF-4394-96C9-A8A8DCA503F3.jpeg
86F97CB2-49EF-4394-96C9-A8A8DCA503F3.jpeg (190.53 KiB) Viewed 2251 times
Sgt. Baker started talkin’ with a Bullhorn in his hand.
Post Reply