|Grounded Grid TRANSCENDENT line
Copyright 2008 © Troels Gravesen
- couldn't agree more!
April 2008: Making a test on the sound
quality of capacitors is a difficult task. In any
scientific work we would as precisely as possible
describe the conditions under which the experiment was
performed because our work doesn't hold any credibility
unless others are able to reproduce - and possibly
confirm - our results.
At a certain point I made a switchboard allowing A-B testing of up to six different caps and much to my surprise, this wasn't the way to go. Being able to zap between caps in a matter of seconds is highly confusing. After a short period of time you end up not being able to hear a damned thing!
The problem with testing things like this
is that we know what is going to happen and we have all
sorts of expectations about what to hear. We can't help
preparing our mind for the event and we're in for all
sorts of self-delusions.
The complete chain of components going into hifi system is enormous. From the phono cartridge with its phono wires, the cables including cable plugs to the RIAA with its internal wires and coupling caps, the cables from the RIAA to the line stage with its coupling caps, wires again to the power amps - with its coupling caps - and the cables to the speaker crossover - with its coupling caps - before the signal finally reaches the speaker drivers. From phono cartridge to speakers I have 6-7 coupling caps, all adding to the sound of the total system (Garrard 401/Linn Ittok LV II/Dyna DX20, Transcendent RIAA, Transcendent line stage, Audio Mirror 6AS7 PSE 20 wpc monoblocks, JA8008/TW034 DTQWT). And this is only a fraction of all the things that - more or less - adds to sound colouration. All caps in the current chain of components are high-grade silver or silver/gold caps, cables are silver plated cobber in teflon wrapping and I claim I hear differences when I change this single cap in the Grounded Grid line stage. I'm also sure that if anyone made me do a blind test on 5 different caps I'd probably be in deep trouble. That's how difficult I think it is.
I'm not going through the caps seen below and give a detailed description on each single cap. The silver/1% gold is the best followed by the Jantzen Superior Z-cap and the Russian 0.22 uF alu/teflon caps. The latter two I find almost the same. The 1 uF Russian alu/teflon giant was a disappointment, lacking in resolution despite a decent tonal balance. The brown Russian "cookie" isn't bad at all - if you listen to classical acoustic guitar and nothing else - and maybe harpsichord. Smooth and sweat but not able to keep apart complex orchestral works. Kind of surprising... Resolution is one thing - but one cap can display good resolution as long as you don't feed it complex musical signals. I'm not an expert in the transmission of electrical signals, but I see (hear) that one important parameter is the ability to transfer complex signals, i.e. electron load, amplitude and different frequences at the same time. Some skilled in the art of designing caps may tell us why this is so.
I've been listening a lot to vocals and piano for these tests. To my ears the most difficult sounds. The Steinway piano on Keith Jarrett's The Köln Concert was one of my favourite tracks. I've had this record for more than two decades. It contains both quiet and loud complex passages and covers a wide frequency spectrum. Any system will be put to the test from this recording - not least the phono cartridge and loudspeakers.
I have ordered 1 uF Mundorf MCAP Supreme
Silver/Gold caps for comparison and more to come when
these have been tested.
20-05-2008: To make a long story short: These Mundorfs will stay. They leave all caps tested here behind. The prototype silver/gold is good, really good - but the Mundorfs are better. The overall tonal balance from these two caps are much the same but the Mundorf excel in the level of transparency - and I'm a sucker for transparency. If a cap is slightly bright I can tune my speakers accordingly.
More cap test, Feb-09
From SOVCOM I bought some more caps, just to know first hand what these Russian vintage caps can do. Initial plans were to test them in my 300B amp, but the GG preamp is a convenient amp for testing caps. The three caps seen above were all tested against the Mundorf Silver/Gold cabs and the PIO caps really aren't bad at all. Surprisingly good, actually. The Mundorfs may excell in overall resolution, but I might as well pick one of these two PIOs for smooth and balanced presentation. The Silver Micas are some chunky beasts and to cut a long story short, I might as well leave these caps in the GG for good. These cabs can be stripped from the metal case (magnetic) and put into some wooden containers filled with wax. I got two of these caps for 17 US $. Two 0.22 uF Mundorfs are ~82 US $.
The Final Mods
I strongly believe it doesn't get much better than this. If you think you may have a better line stage, drop me a mail. The impact on sound from the latest mods is arguable, but possibly a slightly more easy-to-listen-to presentation - and it wasn't too expensive and for the benefit of the doubt.... As always the basic circuitry and coupling cap(s) is what has the greatest impact on sound.
Feb-09: I really shouldn't have made the statement above, because I've recently tried a TRAM w.o.t. line stage and driving the modded Audio Mirror mono-blocks, this amp beats the GG in the midrange. The TRAM from diy-hifi-supply/Hong Kong is no longer available, so I'll have to clone this line stage. I thought I was in for some years of peace on the line stage front, but apparently not....
The final-final mods
It's always a good thing to go back and
see (hear) if the changes we make really are worth while.
So, I re-installed all the original components - except
the coupling caps - and to my ears, it didn't sound any
different from all the Black Gate stuff. I've tried
expensive caps for power supplies in other amps and
always found the benefits to be small, if noticeable at
all. The coupling caps are important, no doubt about it.
This is where I would spend the money. Two good caps is
all the GG needs - to my ears.