Upgrading the Acurus Pre

I did not know the LS-11 would put out 10 volts...
And I never ran a crosstalk sweep, just at 1khz. I did not realize crosstalk changed that much with frequency.

Ya do nice work Kevin. I do apologize about the knobs and faceplate. I run that unit before washing my hands after coming in from the field sometimes.
 
Being able to overlay before and after traces is pretty cool...
 
laatsch55 said:
I did not know the LS-11 would put out 10 volts...
And I never ran a crosstalk sweep, just at 1khz. I did not realize crosstalk changed that much with frequency.

Ya do nice work Kevin. I do apologize about the knobs and faceplate. I run that unit before washing my hands after coming in from the field sometimes.
Click to expand...


Oh yeah 10+ volts out pretty easily.

It is pretty common to see 6dB or more per octave increase in the crosstalk numbers.
Here's what the Audio Critic had to say about crosstalk in their design review and measurements of the Acurus L10, "Careful use of ground planes prevents crosstalk between channels and unselected inputs. This care was reflected in the superb measured crosstalk. Even in the less good channel it stayed below -90 dB up to 1 kHz and then rose at a 6 dB per octave rate to -71 dB at 20 kHz. For comparison, identical mea-surements made by Stereophile on preamps costing up to an order of magnitude more than the L10 are not this good at 20 kHz. For example, Stereophile measured a separation figure of -46 dB at 20 kHz on the $2000.00 Krell KSL, and the $4500.00 Krell KBL measured -60 dB at the same fre-quency."

No problem on the cleanliness of the unit and yours was far from the worst I've received. It only took about 10 min in hot soapy water to wipe those knobs clean. The worst pre's I get are those that have seen use by a heavy smoker. I've had a few come in with knobs that had yellowed cigarette tar/smoke imbedded in the outer rim of the volume & power knobs. Thats some tough stuff to get out and it never really fully comes out, hot soapy water doesn't touch it and even after soaking the knobs in acetone they still show yellowing from the smoke and tar. But I always try to clean them back up becuase it only takes a few minutes once its already apart and the pre looks so much better after reassembly.
 
Liking this thread, very nice work Kevin. Currently running a RL11 in my main system and I have a 28k waiting in wings I want to try next.
 
Geegz, The 28k is a nice preamp. I had one for several years that I upgraded to use a custom external power supply that I housed in an original Aragon IPS chassis (the triangular one). I used separate transformers for the remote circuitry and analog circuitry and split the ground planes inside of the 28k so that the two supplies didn't see each other. The only downside was that it needed a 5-pin XLR to handle all of the feeds from the external PS. I sold it recently to a local audiophile that had previously bought one of my modded L10's.
 

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By the way, thanks for the kind words on the quality of my work. Its always nice to hear good things from other DIY'ers as they're a critical crowd. Its a lot easier to please those folks that aren't as knowledgeable in this hobby.
 
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Putting Kevin's upgrade to the ear, while opening up the smoked 400.
Was pretty drunk Wednesday night...just now feeling human...
 

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I don't suppose you had your SPL meter out for that party??
 
Yesd I did as a matter of fact but not on when the 400 smoked. It smoked on "God Particle" BTW. We were bin the 125 to 129 db range most of the night...
 
They've been here for as long as I have....since 86....Except the one to the south...and that house has been vacant for a year and a half..
 
Kevin....very sweet pre bud...I might be hard pressed to tell the difference between this and the Coherence in a blind test. Now....if the Coherence was in Batt Mode I think I'd have a chance. Maybe a difference in piano...
 
laatsch55 said:
Kevin....very sweet pre bud...I might be hard pressed to tell the difference between this and the Coherence in a blind test. Now....if the Coherence was in Batt Mode I think I'd have a chance. Maybe a difference in piano...
Click to expand...

Well the Coherence is a helluva pre so the fact the modded Acurus is in the same ballpark as it is a good thing to hear. I'm really partial to the Acurus pre's for the price the build quality and design are hard to beat.

125 - 129dB RANGE!!!
WTH man you are close to breaking windows. :)
 
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