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Paul Spencer

DIY audio: what are you building?

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On 16/05/2019 at 12:30 PM, mwhouston said:

The tranni box box is two 12V 300VA Trannies back to back to produce 250VAC and 12VAC for the two 6V filaments (in series). 

Damn, I thought I was the only one who used that method.  :) 

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46 minutes ago, aussievintage said:

Damn, I thought I was the only one who used that method.  :) 

I’ve used it dozens of time of a small and large scale. My tube preamps run from a 24V 1A AC wall wart that backs into the secondary of a small  24V step down Tranni to give me ~250V. 

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36 minutes ago, mwhouston said:

I’ve used it dozens of time of a small and large scale. My tube preamps run from a 24V 1A AC wall wart that backs into the secondary of a small  24V step down Tranni to give me ~250V. 

I use a 12Vac wall wart, but, same.  Much easier to get than a 'proper' valve power transformer.

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6 hours ago, aussievintage said:

 

What a lovely looking machine.  That certainly was a different era in electronics.

 

Sure is and 50 years later it is still one of the best tube testers around.

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Posted (edited)

Can anyone see what I have done wrong here TWICE! All values are correct but here is a hint - look at the red wire which connects the positive voltage. Only three guesses gents. 

B1F862FB-C61B-4FBD-B282-AD3D08B3E91B.jpeg

Edited by mwhouston

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Posted (edited)

The hybrid headphone amp (LeManja) is completed and sounding good. Still trialling the limiting resistor for the reg but all else checks out. With a  universal front end any 12A?7 can be installed with no adjustments to bias etc. The backend is driven by a PT2308 - a dedicated headphone very low distortion driver chip (Class A/B). The chip runs on 7V max so I’ve used a 6V reg. 

 

About to have a be a big listen.  Current tube is a new Ting Sol gold pin. 

CBC1BD20-9421-49E0-A585-1BB299C8C1FA.jpeg

82255926-15BA-419C-9CAE-294D4724DF2D.jpegAfter seven hours on the end of this new HP amp I am extremely impressed. So very pleased. It will go up for sale. PM if interested. 

Edited by mwhouston

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I think I want this t-shirt - in fact I’ve ordered one. My wife won’t get it - in fact I can only think of 1 friend who actually would haha IMG_1479.jpg

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7 hours ago, mwhouston said:

Can anyone see what I have done wrong here TWICE! All values are correct but here is a hint - look at the red wire which connects the positive voltage. Only three guesses gents. 

B1F862FB-C61B-4FBD-B282-AD3D08B3E91B.jpeg

Isn't V+ supposed to be 4?

 

Cheers,

 

Alberto

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1 minute ago, betocool said:

Isn't V+ supposed to be 4?

 

Cheers,

 

Alberto

No 8 is V+. But you are in the right track. 

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31 minutes ago, A J said:

I think I want this t-shirt - in fact I’ve ordered one. My wife won’t get it - in fact I can only think of 1 friend who actually would haha IMG_1479.jpg

👍 Where’d you order that from mate?

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I'm just a lowly part swapper so not really building.

 

Installed some better caps on the out put of my old bog standard CD65, an easy improvement. Removed the remote and Digital board to utilise the rca holes to mount some ETI sockets.

 

Might get me back into listening again.1173739948_ACaps.jpg.de084fec69350878843036de1f4d6631.jpg

 

 

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8 minutes ago, Muon N' said:

I'm just a lowly part swapper so not really building.

 

Installed some better caps on the out put of my old bog standard CD65, an easy improvement. Removed the remote and Digital board to utilise the rca holes to mount some ETI sockets.

 

Might get me back into listening again.1173739948_ACaps.jpg.de084fec69350878843036de1f4d6631.jpg

 

 

I hope it gets you back into listening. Very important. 

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@mwhouston I think they will do it, and I might even look at stealing the signal from after the first op-amp as well.

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If you liked my three of a kind in my “Wood Cheek” series hopefully you’ll like five of a kind. Since the last images I have made a hybrid headphone amp (LeManja) and a 180W Class D Tripath power amp. All have external PS. Really there is seven in the series but two of the preamps “Elite” and “Grace” have gone to other homes where they are well loved. 

 

In the image left left to right - front to back;

  • 180W power amp - “Njira”
  • hybrid tube and chip headphone amp - “LeManja”
  • EAR834p phono preamp - “Calibre 834”
  • Psvane 6SN7 globe preamp - “Elite”
  • Chuguang 6SN7 preamp - “Icon”

All are for sale and if interested PM me. 

 

4BB8B5D0-007B-4FB1-B3E3-22A4375E7E0E.jpeg

67A94C3F-9C6B-4772-9609-55AB6DF045ED.jpeg

A83DC837-5302-4AFE-87BC-667D39B1A49F.jpeg

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20 hours ago, keinesorge said:

In the t-shirt pic... the resistance has been shorted.

Isn't that why It's Futile? :)

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