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In the Forum: Melquiades Amplifier
In the Thread: Valve Preamplifier for Macondo/DSET
Post Subject: All sourcesPosted by anthony on: 8/16/2020
 Romy the Cat wrote:

Again, it was very interesting, but… Let agree that methodologically you did not try Placette as it performance was masked out by you need to use your Neurochrome buffer to get gain. Your chain will sound as the worst element is and in case of 10Y you have the worst element removed. I do have high high probability that if you were able to run Placette and 10Y directly then they will sound identical as the same volumes. I think it is simple to test. I do not know what output in your Phasure DAC. Get any DAC with a op-amp in output stage, most of them are. Find where a feedback provided to the output op-amp and reduces it to gain10-12dB more gain from the DAC. If Phasure DAC has no op-amp in output stage, then get any other DAC. The quality of the DAC is not import you need it purely foe prove the methodological concept. Then repeat the experiment. I think that you will find then Placette will hold his own.

Yes, true.  A few more observations about the listening:

Having one preamp playing for extended periods always gave me the best sound, whether that was the Placette with the Buffer or the 10y.  When the 10y was in for extended periods I thought it worked better than when swapping them in an out to do relatively quick comparitive listening.  Likewise, when the Placette was in for extended periods I thought it sounded better than when swapping it in an out for quick comparitive listening.  Psychoacoustics?  Probably.  There are guys here that buy into the whole cable settling theory but I do not know...all I know is that when swapping things in and out that the sound was not quite as good as when things were left in place for hours or longer...perhaps it was my mood at having to change all those cables.

The quick comparitive listening was a little confounding.  When in for the long run I thought the 10y held a larger advantage than when doing the quick comparitive listening.  Swapping things in and out more quickly the sounds became more or less the same and I was really struggling to hear the 10y as being any better than the Placette at all.  I used my observations from the longer term listening as a starting point in the short term stuff and they just were not observable to the same degree.  As I reported, there was not much in it.  Perhaps it is the dac HF issue and DSET poisoning you mentioned earlier.  Sounds like it.  Maybe there is just very little between the two, which is an excellent outcome for me.

I the past few weeks I have purcased a Pioneer UDP LX-500 universal disc player so that I can listen and watch my Bruckner and other DVD's and Blu Rays.  Well, like pretty much everything these days it is 2Vrms output and needs some gain to get loud enough.  I played that Gogol Suite CD you mentioned earlier in the thread (to scope out how much gain I might really need) and used pretty much the entire 18dB the 10y had to offer...through the Placette without any gain it was like trying to listen to whispers.  Anyway, point here is that I need gain from my dac, disc spinner, phono stages, even from the little dac I use to stream Tidal because none of them give more than 2Vrms output.  That is my issue.

To my ears there is very little separating the Placette and the 10y.  I think I may be able to improve the 10y once it is boxed up with a more ideal layout and perhaps also with an unregulated power supply.  The Placette could possibly be improved by using a different dac and by using one of Guys buffers for gain which in essence is exactly the same concept as the Buffer I am using.  Guy has made it clear that nothing more is going in the case of my Placette and that if I need gain there will be another box for his buffer.  How that works for multiple sources I have not yet figured out.

In the end I have breadboarded a preamp with gain that at least runs in the same league with the Placette.  Two things about this were certainly not expected:  firstly, I did not expect to be able to get the Placette working as well as it does now, but sorting out the power supplies has really helped as has the polarity thing with much of the digital music I listen to; secondly, I did not expect the valve preamp to be so immediately successful.  Sure, it is a proven design with SS output and I did my reading between the lines to choose a valve that drew enough current, was not microphonic, and gave a sound that was not overtly sweet or warm, but I only gave the project a 50% chance of success and even then after much, much more effort than has gone in thus far.  That a DHT is so neutral and transparent and can compare to modern engineering such as the Placette is extraordinary.

 Romy the Cat wrote:
So, where it lives you. Obviously if you have frond-end with more output then I am very convinced that Placette will fulfill all your expectations, I am not kidding it is very hard to beat it. 

Three weeks ago I would not have agreed with this statement, but now I do.  The Placette is very hard to beat.  If both systems were optimised, I am not sure the 10y will beat it, but they will be more or less equivalent.

 Romy the Cat wrote:
What is very important to understand that in case you have both of the scenarios implemented then you should have identical result the end. Another very important message you might consider is that in case of your 10Y the main beneficiary to sound is not the quality of tube or your auto-former but a presence of preamp that acts and post-DAC low pass filter.

I am certainly not ruling that out, and will mull over consequences and actions in relation to HF and dacs, but I do need gain from all my sources.

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