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1. Harrison Labs: Sounds bright, hard. Smeared soundstage. Compressed and poor low level details. Basically throw away SQ.
2. DIY Belden: Sounds very natural. Good soundstage and low level details. For general usage.
3. DIY CAT5: Very musical and smooth. Very good low level details. Very good soundstage. Can be used to tame a slightly bright system
If you are listening at 12 or 2 o'clock, you are fine. But if you are listening at 9 o'clock, the signal may be too hot. You may need an attenuator. Inline attenuator is very convenient. But a cheap one can easily destroy SQ.
Follow Ups:
Tried a few different ones and never liked them. My take on the "sucks the life out of the sound" comments often related to these is that it screws up the phase in certain bandwidths.
Unfortunately, I hear the same problem with PLLXO's.
that requires system matching.Historically, a full function preamp had 40 db for phono and 20 db for line sources. The latter is typically too much for modern digital sources having enough gain (if not proper impedance ) to drive a power amp directly. Mine works great with 58 db to drive my medium output MC cartridge with only 14 db for line. Obviate need for SUT while not overdriven by DAC.
Edits: 03/03/25
I used a decent in-line pair of -10db attenuators years ago between my CJ Prem.3 and power amp. The CJ just had too much gain with volume reaching extremely loud levels before a 9 o'clock setting on the vol. control. The attenuators allowed me to "maybe" get to 10 o'clock on the vol. setting, but after a couple weeks, I realized they were sucking the life out of the music. Went back and just lived with the extreme gain.
Unfortunately, I can't remember the product manufacturer, but I'm pretty sure I researched and didn't cheap out on my purchase. Regardless and as already mentioned, this is the type of product you will just to buy and try in your system....hopefully with a return option.
Your comment about the attenuators sucking life out of the music makes some sense to me. I have found that good "gain matching" between components will help with dynamics. This is one reason why passive attenuators don't sound quite right is some systems. Sufficient "gain matching" on the preamp & amp side seems to help with dynamics w/o the need for life killing inline attenuation.
As for passive preamps, the only passive setup that I had that sounded decent consisted of a CDP source that was especially 'hot' and robust on the output signal (Cary CD 306/200) and an amp with a good amount of gain along with speakers that were somewhat sensitive. I tried the passive preamp on more typical gear and it was a little lifeless.
What sucked the life out of the music for me was the hiss I got without 10 dB attenuators (PS Audio DS DAC Mk 2 - PS Audio BHK preamp - BHK 250 amp - GoldenEar Triton Signatures).
Too much gain with this combo. Noisy. The attenuators were a godsend.
I've since been using a Dennis Had Inspire 300B amp without the attenuators and found my sweet spot.
Too much gain can be a double edged sword.My first Class D amp was the PS Audio HCA-2. The early models had 30dB gain and worked great with a passive preamp. On the other hand, the background hiss was audible with an active preamp especially with somewhat sensitive speakers. Without announcing it PS Audio lowered the gain on newer versions of the HCA-2 amp.
On the Cary side, some of my favorite electronics came from Dennis Had including the budget friendly AES/Six Pac EL34 tube monoblocks. I thought the SLP-05 preamp was probably the best tube preamp I ever owned and I really enjoyed the Cary CD 306/200 CD player. (The 306/200 had a somewhat 'hot' and robust output signal making it a great source component for a passive setup).
Edits: 03/04/25 03/04/25
My current setup gives me "just enough" gain with my rather sensitive speakers. The amp is, of course, single-ended (RCA) with volume cranked up to 11 lol. The 8 WPC 300Bs and 6SL7 driver provide more-than-adequate gain in my small-ish LR.
Patrick McDonald, who was the engineer for the music (and has a part in the movie playing himself) for "This is Spinal Tap", taught me how to engineer a record.
I love that the "goes to 11" thing just won't die!
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
How about one of these?:
https://www.schiit.com/products/sys
They are supposed to be pretty clean.
I use one for bi-amp setup.
I have no direct experience with the Schiit Sys but I've had a couple other Schiits including the Freya + and Kara. Both of these can be run in fully passive mode, buffered passive mode, but in my setup I much preferred them in active mode with gain.
The MAIN thing passives are known for is ultimate transparency but IMHO sometimes they sacrifice too much in other areas. They are very cable dependent and system component dependent, more so than when using an active preamp, so short cables and component matching with a passive are much more critical.
The SYS is totally passive and has no effect on the sound when in the circuit. I use one to balance the ARC tube amp playing the mids and highs with a Mc transistor amp for the bass. Changing leads didn't change the sound so far as I could hear. I use this setup for music.
LowIQ
One correction on that passive preamp. It's max output impedance is 2.5k not 5k
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
What were the values of each attenuator in your post?
What were you attenuating? From what to what?
Now I realized that I am too eager to help. Take easy.
I was just looking for context in your findings. To simply rank the attenuators doesn't offer much.What were the resistor values for each attenuator in your post and the dB attenuation? Were they all the same? Different? What were you attenuating? From what to what? And what were their respective output / input impedances? Too many unknown variables for me.
Without the details surrounding each attenuator set your ranking generalization isn't very useful IMHO.
Edits: 03/06/25 03/06/25
I am not wiling to share the design.
Here is a little information which is not top secret.
Input impedance 10K. Amp input impedance 47K. Default attenuation 4:1 -12dB. Used on which side (output or input) this is top secret. I have the schematic and the formula to calculate the attenuation. Also connector model and cable model.
Be nice.
I'm not nice because I was curios about the detail to better understand your claims? I did not realize the details are "top secret".;-)
Edits: 03/08/25
Thanks for the info.
Does anyone know of a decent sounding attenuator that is not diy?
"Does anyone know of a decent sounding attenuator that is not diy?"
LoL. Of course not.
Years ago I used a pair of these to match an Audio Research SP9 preamp to a pair of Bryston 7BST power amps with good results. Opinions on their effects on sound quality are all over the place - your own ears are the best reviewers. You have to order them direct from Rothwell in the UK.
Do you state the input impedance of your amp when ordering?
If not, then how would anyone know what the db loss will be?
Above is a (approximately) 10db attenuator (1/3 of the input voltage) but the input impedance of the amp will be in parallel with R2 so there will be more than a 10db loss.
In this example if the input impedance is 10k then the value of R2 becomes 5k (10k//10k) and the db loss is now 14db (1/5 of the input voltage). If the input impedance is something different, then there will be a different amount of db loss.
I would just build my own. That way I can make the db loss whatever I need it to be.
https://www.sowter.co.uk/decibels.php
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Tre said:
"Above is a (approximately) 10db attenuator (1/3 of the input voltage) but the input impedance of the amp will be in parallel with R2 so there will be more than a 10db loss.
In this example if the input impedance is 10k then the value of R2 becomes 5k (10k//10k) and the db loss is now 14db (1/5 of the input voltage). If the input impedance is something different, then there will be a different amount of db loss."
A few basic questions . . .
My understanding, based on our previous discussion elsewhere, is that putting a voltage divider on the preamp / source side of an interconnect affects the output impedance of the preamp / source. And that it also interacts with the capacitance of the interconnect itself, which affects the low pass rolloff point.
In that scenario (voltage divider on the preamp / source side) does the value of R2 also change the input impedance of the amp?
My understanding was that, if the voltage divider is on the amp side of the interconnect, it has no effect on the output impedance of the preamp / source and it doesn't interact with the capacitance of the interconnect.
Do I have this right?
Also, it would seem to me that there wouldn't be any advantage in lowering the input impedance of the amp significantly. Especially if it is low to begin with, as is the case with a SS or Class D amp where 10k to 20k is typical. Wouldn't lowering it further just make it harder to drive?
If minimal change to the input impedance is desirable, wouldn't it be better to use higher values for R1 and R2?
For example, if you used 2M for R1 and 1M for R2 it would result in the same amount of attenuation and the input impedance of the amp would be 9.9k rather than 5k.
It seems like the main concern would then be the effect on the low pass rolloff. For a tube amp it might be easier to determine that since tube data sheets list capacitance specs. But what about SS and Class D? Do manufacturers publish those specs or can they be easily measured?
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