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Paul Spencer

DIY audio: what are you building?

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Posted (edited)
On 23/05/2019 at 3:25 AM, 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

 

 

 

On 23/05/2019 at 5:08 AM, Muon N' said:

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

Well that's interesting, I was going to assume that with two dual 5532DD opamps after my DAC chip the two channels L&R would go to one opamp and then out of that onto and into the next opamp and then out and onto the coupling caps...essentially.

 

But I'm glad I had a look at the schematic, as the L out from the TDA1541 goes to one of the two dual opamps and the R out from the TDA 1541 goes to the other of the two dual opamps.

 

Hmm...at least I'll be good to go and take the signal from close to the outputs from these opamps, but I'm not doing away with any of them this way! I better trace what is going on around each one tomorrow.

 

Edit: arrg..I think that one dual is used as two opamps for one channel.....each.

 

Edit: OK, I'm slowly learning :)

 

They are coming out of pin 3 and back into pin 5, so I need to take it from after pin 3, I think. Hang on! that can't be right! unless this is how they do the U/V conversion? I need to think about this more. OK, I think I have it now after leading myself astray just then, so confusing the first time :$ I take it after pin 1 A-Output from each dual opamp. So they are going into A-Input on the first half and A+Input is going to ground.

 

5532DD.jpg.c7abfa76270b29128ddd319fc749552e.jpg

Edited by Muon N'

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Posted (edited)
On 26/05/2019 at 7:58 AM, Muon N' said:

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

:D

 

I suppose in "trek" parlance, the reference to an externally shorted resistor is not in full light of the borg intention and welcome address...

 

We are the Borg. Lower your shields and surrender your ships. We will add your biological and technological distinctiveness to our own. Your culture will adapt to service us. Resistance is futile

 

Unlike the resistor, the "crew" were never shorted.  The nanoprobes screwed them over.  IMO, the borg intention would be better illustrated with additional electron pathways (nullifying the resistance) and borg paraphernalia in and out of the resistor body.

 

My apologies to AJ.  I do like the shirt (its a nice shirt) and i will not be adding to the thread detour.

Edited by keinesorge

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Finished my stands, pretty happy with the result.

 

 

Paradigm 9se stands.JPG

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49 minutes ago, Janus77 said:

Finished my stands, pretty happy with the result.

Looks good.

What sorta spikes did you use for the build ?

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I got spikes from a UK seller on ebay.  Search for "Monacor fine version".  The speakers already had feet on them.

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1 hour ago, Janus77 said:

I got spikes from a UK seller on ebay.  Search for "Monacor fine version".  The speakers already had feet on them.

👍

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Posted (edited)

Cool, no magic smoke evident xD

 

A little less gain, not an issue in my system, and things sound a little cleaner/smoother on a quick test.

 

Have to have a good listen shortly.

121093347_Afterfirstopamp.jpg.f1aea92c78841a18159a52593c5faf33.jpg

Strrings are more prominent, as are some things that were previously more recessed, and bass is more layered. The slight loss in gain isn't all that evident, and the presentation sounds more complete at very low levels.

Edited by Muon N'

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I wasn’t happy with the chip board in the first build of the hybrid headphone amp LeManja. I have now replaced it. Better matched parts, neater build and some upgrade tweaks along the way.  Still only low ESR caps and I bypassed the output caps with polies for better HF reproduction.  Sound glorious, very, very happy. 

 

Tried it with both 32 and 250ohm Sennheiser and Beyerdynamic phones.  It drove both loud with no distortion or clipping. 

 

It will be going up for sale so PM if interested. I should have a price by tonight. 

349EBD3B-04F0-4723-972D-5C1CA25EF8FB.jpeg

BA496E23-8EC5-4777-A482-BCF1B12E6AE0.jpeg

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Yet another portable headphone amp. In the past I have built a number of Oatley K272? Tube and chip devices. Also a few CMoys. Lov’m. But after building the latest home base unit and hearing how good the PT2308 chip was I have decided to make an all PT2308 chip based unit.

 

Because I take these overseas, on the train and use them on the plane I am trying to get size and weight down. That imposes more design issues. The amp is built on Vera-board and is about as small as I can get it. 4 X AAA lithium’s will power the unit. Should be complete in the next few days. 

48BA4581-1B15-45A7-A6B4-4B0B913583C6.jpeg

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Be interesting to see. I love me a good headphone amp.

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1 hour ago, betocool said:

Be interesting to see. I love me a good headphone amp.

Hope to get into it tomorrow. I needed some more bits. 

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Posted (edited)

Finally, after a few stuff-ups, got the cct. brd. for the next portable HP complete. NP input caps and LESR output caps. Yet to add some hookup wires and then on to drill the small ABS enclosure. Not hard to see how small it is. At 67 I’m finding it harder and harder to work at this level. It’s on Vera-board. 

7177957E-12BA-48C8-934E-648BFD918DC1.jpeg

Edited by mwhouston

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I feel the pain!

Though doing better than myself and you have 9 years on me, have some mileage to go on you still, Mark :thumb:

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1 minute ago, Muon N' said:

I feel the pain!

Though doing better than myself and you have 9 years on me, have some mileage to go on you still, Mark :thumb:

The shakes and poor eyesight make it hard. Big stuff, tube amps etc. OK!

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With you there, Mark......I hate circuit board work, especially very crowded ones, and forget that SMD stuff xD that I'll defiantly leave for the youngins.

 

I try and confine myself to tinkering on the bigger stuff, and point to point construction...so much easier.

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1 hour ago, Muon N' said:

With you there, Mark......I hate circuit board work, especially very crowded ones, and forget that SMD stuff xD that I'll defiantly leave for the youngins.

 

I try and confine myself to tinkering on the bigger stuff, and point to point construction...so much easier.

Agree. 

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