Poundland 45

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Cressy Snr
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#121 Re: Poundland 45

Post by Cressy Snr »

The tube rectifier returns. The cap goes back underground.
57F2A2D4-5678-4F0C-850E-5C085D79C61A.jpeg
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“Idiots make it into every company. They tend to interview well.”

Bonnie Garmus (2022) Lessons in Chemistry.
Cressy Snr
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#122 Re: Poundland 45

Post by Cressy Snr »

I like it like this. Interesting that you can keep making ‘improvements’ then remove them all and find you have improved things again.
Just shows how completely unreliable the trusting of one’s ears can be.
“Idiots make it into every company. They tend to interview well.”

Bonnie Garmus (2022) Lessons in Chemistry.
Cressy Snr
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#123 Re: Poundland 45

Post by Cressy Snr »

Mind you, me of all people should know full well that the mind lies through its teeth, makes up stories and is not to be trusted.
“Idiots make it into every company. They tend to interview well.”

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izzy wizzy
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#124 Re: Poundland 45

Post by izzy wizzy »

I'm not sure it's about ears being unreliable but more about how we can overthink a design. I don't mean that to be a derogatory comment.

I think in this hobby, we have a lot of noise to filter in order to find our place or recipes. The notion that we have to control (regulate) stuff is up for grabs but it's a hard path to avoid. Coz you can always make it "better" by regulation. As Nick says, the devil's in the small details.

I've diappeared down similar rabbit holes for years. Now I don't change more than one thing at a time and then live with it for ages to see if it really is better for me long term. Might sound "better" on a short listen but over time, maybe not so.
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Ray P
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#125 Re: Poundland 45

Post by Ray P »

Now, stop fiddling and enjoy listening to your music Steve - I'm assuming that's why you built it - if you feel the need to do something buy yourself an Airfix model or something...
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#126 Re: Poundland 45

Post by Cressy Snr »

I’ve got the kitchen to decorate before Christmas, so I won’t have time to fiddle with electronics.
Eckhart Tolle, one of the pioneers of mindfulness based cognitive behavioural therapy, makes an interesting observation in his book, ‘The Power of Now.’
‘The inability to stop thinking is a terrible affliction and has caused endless suffering over millennia.’
Fiddling with electronics, shuts up the incessant mental chatter for a while and makes me feel calm. I don’t negatively judge the paths this kind of tinkering takes me down any more. I let these paths and diversions simply be. The fact that I’m back where I started just ‘is’ There’s not a lot else to say. It’s a therapy and a very effective one.
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Ray P
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#127 Re: Poundland 45

Post by Ray P »

Yeah, but I'm being selfish Steve, I'm looking forward to hearing your 45s, et al, at Owston...
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#128 Re: Poundland 45

Post by Cressy Snr »

The longer I’m at this game, the more I want simplicity and things reduced to their essence.
A simple, permanent amp for day-to-day listening, and a breadboard for messing about with, is probably the best way to go I think.
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Cressy Snr
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#129 Re: Poundland 45

Post by Cressy Snr »

I've wound up this project. Below are the up-to-date schematics:
Screenshot 2021-11-17 at 19.31.35.png
Screenshot 2021-11-17 at 19.31.35.png (75.27 KiB) Viewed 1448 times
Screenshot 2021-11-17 at 19.30.28.png
Screenshot 2021-11-17 at 19.30.28.png (77.96 KiB) Viewed 1448 times
“Idiots make it into every company. They tend to interview well.”

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Cressy Snr
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#130 Re: Poundland 45

Post by Cressy Snr »

The above stuff is about as simple and minimal as it gets and the sound is great.
There has been a lot of evaluation of the effects of different power supply schemes and also input/driver valves. I have recorded all of this in the thread.
I have settled on the schematics above, because taken together they give the most musically satisfying sound from the pair of 45s, pushing it as far as it will go within the constraints of the driver tubes I have available.

The driver valves tried out have been ECC88s, ECC82s and ECC81s. The ECC88, in theory, is the most linear driver valve and should give the lowest distortion, it also has sufficient gain to drive the output to full power, and for a while, it gave me what I thought I ought to have wanted out of the circuit. Eventually however, it began to sound emotionless and frankly boring.

The ECC82 was nice and I could have lived with it long term but there was insufficient gain as a single stage, which led, unfortunately to a sound that lacked dynamics and speed.

The ECC81 is the best overall, combining the tubey sound of the ECC82 with decent levels of punch and speed, without everything becoming aggressive or harsh.

One could be forgiven for thinking that the ECC81 is a bit of an insult to the 45 and it might very well be, but as a system it does a decent job of driving a small DHT.

A couple of stages of cascaded 26 or British battery valves, would probably wipe the floor with the ECC81, but complexity, size and weight would increase, with DC supplies being mandatory for the input and driver stages at least, plus another four heater transformers, making six in all, plus mains. Frankly I simply can't be arsed with all that malarkey.

I think this little amp fulfils the design brief I had in my head. It is super-compact, electrically quiet and gives me a nice big dollop of the magic of the 45. I love it.
Last edited by Cressy Snr on Wed Nov 17, 2021 8:15 pm, edited 1 time in total.
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#131 Re: Poundland 45

Post by Ant »

Cressy Snr wrote: Wed Nov 17, 2021 7:37 pm I've wound up this project. Below are the up-to-date schematics:
Screenshot 2021-11-17 at 19.31.35.pngScreenshot 2021-11-17 at 19.30.28.png
Where have we heard that before :mrgreen:

I bet its different already
Also starring Rex Hamilton as Abraham Lincoln

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Cressy Snr
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#132 Re: Poundland 45

Post by Cressy Snr »

No it isn’t :)
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andrew Ivimey
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#133 Re: Poundland 45

Post by andrew Ivimey »

!
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.
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#134 Re: Poundland 45

Post by steve s »

Steve, reminds me of my 1st decent se amp, ecc81 driving el84, it was rebuilt by me from an old radiogram. I preferred it to every commercial 300b amp I had listened to previously. But that probably says more about commercial 300b amps in the 90s than it being a good amp
Can't wait to hear it at owston
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
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Paul Barker
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#135 Re: Poundland 45

Post by Paul Barker »

the character of the driver is a big influence, Anth; naughty step!
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