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Heifetz

stepped attenuator differences

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39 minutes ago, georgehifi said:

Hi Bob, I would try this first: 

ZYX 1000 Airy 3 cartridge  >  Hashimoto 7 SUT  >  Audio Note Phono (try feedback on and off)  > Lightspeed  >  TS Lim Diva Blue Sky Power Amp. (forget the AN preamp)

 

See if you have enough volume, don't be worried if it's up around 4 o'clock so long as it's loud enough for you, should be as you have the gain of the Hashimoto 7SUT (30db) and the AN phono stage  another 10x gain.

Thank you George,

I have arranged the components as you have suggested and there is plenty of volume. Wow!!

Thank you so much. I'm going analyse the sound now but on first 3 minutes listening I can say that its very transparent. I wouldn't say that its lost any 'tubey' sound. 

Thank you, Bob

 

 

 

 

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1 hour ago, Heifetz said:

I have arranged the components as you have suggested and there is plenty of volume. Wow!!

Everything should sound more open. 

Try the AN Phono stage with feedback on and off.

Off should have more gain,  richer mids, and may have less very low bass. 

Feedback on will be more controlled and should be truer sounding, and should have less gain, so you may have to turn up the Lightspeed more.

 

Cheers George  

Edited by georgehifi

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7 hours ago, georgehifi said:

Try the AN Phono stage with feedback on and off.

Hi George,

Thank you. However, I don't understand what 'feedback' on / off means. My Phono doesn't have a switch marked 'feedback'.

 

Is it the same as a high/low gain switch. If so , then my phono doesn't have one. 

Thx, Bob 

Edited by Heifetz

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10 hours ago, Heifetz said:

Hi George,

Thank you. However, I don't understand what 'feedback' on / off means. My Phono doesn't have a switch marked 'feedback'.

I saw it here under the Technical Specs under input sensitivity.

https://www.audionote.co.uk/m1 

 

The switch could be inside, but also this could just be a measurement only parameter and not user adjustable, or it could have been even on an earlier model. And yes the gain would be affected hi/lo

 

Cheers George 

 

Edited by georgehifi

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On 15/06/2018 at 12:04 PM, georgehifi said:

Here are the differences explained with the series v ladder v shunt, volume controls, the best is "ladder" which is series and shunt combined, especially if it can be done with no contacts in the path (see diagram).

 

http://diyaudio.co.kr/wwwboard1/data/board1/compare.pdf

 

Cheers George

 

 

 

volumecontrol-e1398261583626.jpg.08795d16f8c7563bc1fc116b1d7ebc63.jpg

What is  being shown on the right is the relationship of signal ground to LDR cathode, at exactly the same ground potential, worded as "Fixed No Contact"    

 

Rather,in a good LDR circuit the signal ground and  the "cathode" (- conventional current leaves a polarized electrical device )  , are always separated by a potential difference.  

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1 hour ago, georgehifi said:

saw it here under the Technical Specs under input sensitivity.

https://www.audionote.co.uk/m1 

Hi George,

My Phono is an older model - may be 20 years old. 

But I'll have another look just in case.

However, it does sound great. There is more space and transparancy and there is plenty of space. 

So I'm very happy.

If there was another set up that you might suggest to try then I'm all ears! But this is already a success.

I guess every place where the LS volume knob sits is a 'sweet spot' unlike the usual 'contact' attenuators. Is that correct?

Also, I understand (now) that the job of a preamp is magnify the signal only keeping it 'true' and not add a colour or any other addition on top of the source.

Thank you. 

Thx, Bob

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2 hours ago, Heifetz said:

I guess every place where the LS volume knob sits is a 'sweet spot' unlike the usual 'contact' attenuators. Is that correct?

Yes it sounds the same down low and up high.

To test this you need two gains from the source low and high to be opposingly different. So your hear the two positions low and high of the Lightspeed at the same db level, so then your ears won't play tricks on you

 

Cheers George.

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@georgehifi

Hello George,

I am enjoying the LightSpeed very much. It has a transparency that receives the mids. 

I had a question about the resistors. Would different resistors in the LS change the sound? 

I ask this because in a previous preamp I changed the resistors on the stepped attenuator to the Charcroft 100k 0.4w Z Foil Resistor. I loved the improvement in the character of the sound from that change to the Charcrofts. 

Is it possible to change the resistors in the LS to Charcroft 100K and what do you think the kind of change I might experience?

Thank you, Bob

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32 minutes ago, Heifetz said:

@georgehifi

Hello George,

I am enjoying the LightSpeed very much. It has a transparency that receives the mids. 

I had a question about the resistors. Would different resistors in the LS change the sound? 

I ask this because in a previous preamp I changed the resistors on the stepped attenuator to the Charcroft 100k 0.4w Z Foil Resistor. I loved the improvement in the character of the sound from that change to the Charcrofts. 

Is it possible to change the resistors in the LS to Charcroft 100K and what do you think the kind of change I might experience?

Thank you, Bob

I don't think there are resistors in the signal path.

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1 hour ago, Heifetz said:

I had a question about the resistors. Would different resistors in the LS change the sound? 

 

41 minutes ago, misternavi said:

I don't think there are resistors in the signal path.

Correct, there are no resistors in the signal path, just one LDR.

 

Cheers George

Lightspeed Attenuator MkII Circuit Diagram.jpg

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17 minutes ago, georgehifi said:

Correct, there are no resistors in the signal path, just one  LDR

LDR = Light Dependent RESISTOR  :) 

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@georgehifi

I have read that a battery can be used instead of the mains.

 

Is this something that you advocate and what differences would be noticeable?

Which brand/type would you recommend?

Thx so much, Bob

 

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15 minutes ago, Heifetz said:

I have read that a battery can be used instead of the mains.

 

Is this something that you advocate and what differences would be noticeable?

Which brand/type would you recommend?

Thx so much, Bob

Yes, many use a 12vdc battery, just make sure it's has a 2.1mm X 5.5mm plug, and very important centre is positive.

 

I recommend these rechargeable lithium-ion (li-ion) ones, which would give up to a couple of  weeks of listening, before a recharge is needed.

 

 https://www.ebay.com.au/itm/Portable-3500mAh-DC12V-Lithium-Battery-Pack-Rechargeable-Li-ion-LED-Board-CCTV/182278402926?hash=item2a70a3b36e:g:UTAAAOSwAfVb3UP6

Make sure with the seller it has a 2.1mm x 5.5mm plug and center is positive.

 

Cheers George

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1 hour ago, georgehifi said:

I recommend these rechargeable lithium-ion (li-ion) ones

Hello George,

Is the benefit of the battery due to it supplying 'cleaner' power?

Thx, Bob

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15 minutes ago, Heifetz said:

Hello George,

Is the benefit of the battery due to it supplying 'cleaner' power?

Thx, Bob

Yes even though the power supply that comes with the Lightspeed is a toroidal supply and very low in noise, the battery has just a touch less measured noise, and many say they can hear a difference but couldn't A/B it, it's small but there, for an even blacker background.

 

BTW stay away from SMP (Switch Mode) wall warts they are noisy

Cheers George 

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Is it the power coming through from the mains that is 'dirty' or is it the wall wart that makes the power 'dirty' or is it both?

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Here's a novel little experiment to show how bad SMP's can be, get an AM portable radio set it low on the dial off station, turn up the volume control and go near to an SMP with it, and hear it squeal like a stuffed piglet.

 

Cheers George

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1 hour ago, georgehifi said:

Here's a novel little experiment to show how bad SMP's can be, get an AM portable radio set it low on the dial off station, turn up the volume control and go near to an SMP with it, and hear it squeal like a stuffed piglet.

 

Cheers George

 

I'm sure what you described has that effect.  However what that experiment does, surely, is show how much EMI is coming off the SMPS ... which is impacting the AM portable radio's aerial?

 

Whereas an equally bad result from a crappy SMPS (particularly a 'wallwart') is that they inject crap back into the mains - to 'infect' other components.

 

 

(I always use a hash filter between a SMPS and the wall socket, to stop this hash transfer.)

 

Andy

 

Edited by andyr

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40 minutes ago, andyr said:

However what that experiment does, surely, is show how much EMI is coming off the SMPS ... which is impacting the AM portable radio's aerial?

Yes and also penetrating any unshielded audio cable/equipment in vicinity, and radiating back into the mains.

 

Cheers George

Edited by georgehifi

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1 hour ago, georgehifi said:

Yes and also penetrating any unshielded audio cable/equipment in vicinity, and radiating back into the mains.

 

Cheers George

 

Absolutely, George!  :thumb:  Then again, IMO anyone who uses unshielded interconnects deserves what they get.  :lol:

 

And surely equipment cases - well, those that have 3-wire power cords, anyway - are earthed?

 

Andy

 

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7 minutes ago, andyr said:

And surely equipment cases - well, those that have 3-wire power cords, anyway - are earthed?

Not if they're those stupid wood chassis ones.

 

Cheers George

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1 hour ago, georgehifi said:

Not if they're those stupid wood chassis ones.

 

Cheers George

 

Aah, true - had forgotten about those.  :)  Then again, I have read of those who say a circuit in a wooden case sounds much better than the same circuit in a metal case!

 

Andy

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