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In the Forum: Horn-Loaded Speakers
In the Thread: RAAL “Water Drop” tweeter for Macondo.
Post Subject: The RAAL and an amplifier.Posted by Romy the Cat on: 2/20/2007

 Paul S wrote:
  The "calm HF" effect is something I have long sought but seldom experienced from repro, and I have blamed the amps as much as the ribbons.  Mere HF extension is not enough.  Hard to say whether the amp or the ribbon is typically at fault, but either these ribbons via a crossover are a real bitch for any amp, or the ribbons themselves are very unforgiving of the amp via the crossover.  In my experience an amp typically has as hard a time with these dinky-ass HF ribbons as it would with big LF drivers, and no doubt this has contributed to putting some people off the idea altogether.’

Here is the subject! Under no circumstance I presume that I have my final opinion about it but here are my up to now experiences of dealing with the Water Droop’s peripherals.

The people who know me know that I would not BS myself and others and it I stuck with Melquiades then I have very strong, not ego driven, reasons to do it. I do not have any other amps in my listening room now besides a full-range Melquiades and the Super Melquiades DSET. So, when I was driving the Water Droop stand alone I was using full-range Melquiades with Vintage EVS attenuators in the Milq’s input (they use to be phenomenal and had absolutely transparently sounding devises). All cables in the system are PAD Domonus, not the todays but the “older”… if you know what I mean. The sound of the “bare Water Droop” was  OK with firs order but complete dies with second order at 12kHz. Also, when I moved up on the transition slope with first order the sound very much craped out below 0.8uF it…

Alex suggested that it is the way how it should be as HF over 12Khz there is no musical information but juts noises. Well, I did not really subscribe it and blamed the Alex’s transformer, my filter or whatever else I was able to blame. Alex also suggested that a ribbon should sound better when some LF harmonics supplement it’s HF “noises”… Well, looking what I heard from Water Droop he was correct. Still I was annoyed that a stand-alone driver did OK with first order turn to sound so crappy with second order…. I never seen that a pass-band would be so affected with the filter change…

Well, when I reversed the phase and was able to ingrate the Water Droop with Vitavox then I recognized that I can completely painlessly do go for second order with no negative effects to sound. Initially I thought it is because my Vitavox provide that so necessary for the ribbons” LF harmonics supplement” then I began to question it. I asked myself why the sound does not turn crappy with second order as it use to be what I was driver juts alone Water Droop? Perhaps Alex was correct and the “HF artifacts” should not be head alone but only in context of the meaningful LF? Well, not necessary….

I asked myself: if with my full-range Melquiades the Water Droop turns itself to shit with second order but with the Super Melquiades it does not then why doesn’t I listen the Water Droop stand alone but driven by the Super Melquiades HF channels? I disconnected speakers from all other Super Melquiades channels I drover the Water Droop by only one Super Melquiades’ HF channel.  So what? With the Super Melquiades HF channels regardless of the crossover point and the steepness of the slope Sound was WAY different then with a regular Melquiades. (I did tried the Super Melquiades HF channels on the Water Droop before but it was during my “in phase” story)

“Wow”, - said, this was something that I completely did not expect.

Let see what is the difference between the full-range Melquiades and the Super Melquiades’ HF channel. The driver stage in Milq in ultra fast tube that feels very comfortable in MHz region. The fixed-biased 6C33C is well know as “hard” tube that with improper use become to sound even like a bad SS amp.  The HF in Melquiades electrically restricted by the low pass filter that made by grid resistor and the Miller capacitance of the driver’s tube - it is something about 100Hz The output transformer of the full-range Melquiades at the 20kH when I measured it was caring a full 15W unto 88Khz. However, it said absolutely nothing about the phase variations, distortions or any other nastiness that takes palace in this transformer at HF. I realty have no knowledge to asses the Melquiades OPT’s HF objectively and no auditable experience to interpret the results of my measurements. The friends of mine who know the subject suggested me the realistically and practically I can get out of a full-range Melquiades 9H transformer around 20kHz -21kHz and then the inductance of the primary as long as many other things begin to crap out HF.

Well, when I was making the Super Melquiades DSET and when I was thinking about HF channel I went for isolation between upperbass and HF amplifiers not because I was trying to bet better HF – I did not have any problem with HF of a full range Melquiades. I did the isolation because I recognized sonically the inductance of the upperbass’s driver affected the Vitavox’s voice coil. THAT was something that I was trying to eliminate with my DSET. Still, while I was making my HF channels of the Super Melquiades, knowing that it will be caring juts from 3.8kHz and up, I decided to go for a output transformer of the same core-mass (I need to drive 6C33C’s current though it) but with a VERY limited amount of turns (as little as coupling would permit). Mr. Lundahl picked among his transformers the one with 0.85H that he used for some kind of line-operation, winded it with amorphous core and that I put in the Super Milq HF channel. I do not think that you even seen me telling that my Super Milq has subjectively better HF then a full-range Milq, in fact it was almost opposite because my loading audio-Moronity™. However, the problem was, presumably, that I juts did not have tweeters to discriminate the difference. The Water Droop did not work well with a full range Milq, however with HF of the Super Milq DSET it runs fine… was it the HF out ptrsfpor in the Super Melquiades eventual pays itself off?

Hm… I do not know how about the PP amps. They usually have a lot of asymmetry at HF, not to mention the phase splitters, crossover and switching distortions. Many PP usually use feedback that even further screws up HF. Obviously an A1 SET is the topology to drive the Water Droop but I wonderer if anything ease even further. I presume that if Alex can make a transformer with high ratio then, considering the high crossover point and no needs for harmonics it would be fin to drive this thing with an OTL…  I can see now the Franch Vincent Brient is laughing…

Anyhow, the demands for the Water Droop amplification are high and frankly speaking I would like to see how the Water Droop would behave not with a Super Melquiades level amplification but with a conventual amplifier. The only problem is that the Water Droop dos not travel well and in whomever listening room it goes it will ware this room on itself…

Yes, Paul, you were correct: it is not juts the tweeter but everything all together. Nothing deferent from anything else…

The caT

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