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I received my second Adcom GTP-400 tuner-preamp today. Every bit as nice as the first one, and not surprisingly, they sound identical.
That serves to give me two complete systems with an Adcom GTP-400 tuner-preamp, Rotel CD player (an RCD-971 and an RCD-955AX), a pair of dual mono power amps(an Adcom GFA-545 II and a Rotel RB1050), and two pair of speakers with SEAS woofers (A26RE4 and 25F-EW) and SEAS 27TBFC/G tweeters with minimalist crossovers. I can mix and match the components in any combination, and the sound is very similar.
So, at least for now, I'm pretty much done with acquiring components and speakers. I do have a couple of loose ends to clean up, but nothing major, and I do want to replace the large filter caps in the Adcom gear. Of course, I can still be tempted! So we'll have to see how long I can resist. Any bets?
Jerry
Follow Ups:
Just last night my wife was telling her sister how crazy I was for selling & buying different gear. Now get this, she is talking about my "sickness" that has been going on for some 40 years now. Early in our marriage, about '73/'74, I had a larger model of ADS for mains & Sansui separates. I sold them after 4 yrs & acquired Maggies & Hafler, which I kept for about 8 yrs. I sold them & got something else (a mistake, so bad my mind has erased what they were). Fast forward to now & I have ML Source & ShengYa Integrated. I mentioned that I may sell my Martin Logans & get some Maggies again, which brought on her blank stare at me & her conversation with Sis about what could be wrong with me, I'm never satisfied. I could point out that we've been together for 44 yrs, but that wouldn't work. So I've had 3 or 4 systems over what, some 40 yrs. & I belong in an asylum (SO TRUE), but look in her (used to be "our") closet & there are maybe 50 or 60 pair of shoes, prolly 20 pocketbooks & Lord knows how many jewelry boxes full of bracelets, rings, necklaces, etc., but, according to her, that's normal for a woman. I agreed with everything she said, and that's why we still love each other after 44 yrs.
Everyone thinks I'm strange except my friends deep inside the earth
Let's see, we just celebrated our 53rd anniversary. Over that time, I've had countless pieces of gear. Back when we started out, money was tight, and continued that way for quite a while, so I made do with a lot of low buck stuff; mostly used. I repaired a lot of the early gear, and for a while, made enough on resale to pay for more gear. She never complained! But then things got better financially, and after that, I started swapping gear more often.
I don't think your turnover in gear is excessive. I'd guess most of the Inmates here have turned over their gear a lot more often than you have. If it's a hobby, then I'd expect some continual activity. Otherwise, it's a music appliance for your home.
Jerry
I've heard that Adcom GTP-400 is one of their better ones. Back when my son's old junk receiver that he somehow inherited from one of his fraternity brothers died, I picked up an Adcom GTP-450 that I paired with my old Belles 150A and was quite impressed for a $75 preamp. Have you ever heard the 450?
-Rod
Rod,
Yes, I have, in fact, I've owned 2 at different times. Frankly, I much prefer the sonics of the earlier GTP-350 or GTP-400. The GTP-450 has a remote control, and uses silicon switches to switch functions and inputs. I blame those for the lesser sonics, as the 350 & 400 use mechanical switches.
Jerry
We will be watching you! For even the slightest hint that you are going to buy another piece of gear. No one gets away with saying "I'm Done" and then purchases something new. We will decide what to do with you later but be forewarned....
You still have lots of music to explore! People are literally giving me CD's and thrift stores are selling them at $1 to $2 a piece. There never has been a better time to explore music!
Dave
Dave,
Yes, I'm still a listener, and still buying CD's. My favorite spot is our library's annual book sale. Last year I bought 40 CD's for $1 each. But I've run out of room, so there is an annual culling of less played ones that go to drawers in the garage or donated to the book sale.
I also still have a very good cassette deck, and about 200 tapes I made from my LP's to play in the car before cars had CD players. They are all in the garage, and may be crap by now as they haven't been played in at least 20 years when I transcribed the best of them to CD. I still have a Sony dual tray CD recorder. I was surprised how good some of the LP to tape to CD copies sound.
But now that I have equipment I like, except for some minor tweaking and a couple of loose ends, I am done with the hardware unless something fails.
Jerry
HiJerry,
I know what you mean about running out of room for the CD's. There is a store here now, called the Record/CD Exchange. It is definitely time to do some culling. AFAIK, they only take rock, pop, jazz and blues, but Backstreet Books will take classical. I have a lot of classical!
I don't have many tapes but I do have a Nakamichi ZX-7. One of those items I could not pass by ...
Dave
But I've run out of room, so there is an annual culling of less played ones that go to drawers in the garage or donated to the book sale.
Which is one of many reasons to move to a computer based music library. Space has not been an issue for me, but the ability to instantly access any track from my library in seconds via iPhone or pad has been quite compelling. I've re-discovered old friends that for one reason or another just didn't get picked off the shelf. And spend zero time shuffling disks from shelves and jewel cases to transports and back again. When I get a new CD, it is immediately ripped and added to the library. Time consumed - about two minutes.
Airtime suggested you venture into network based music. I second that motion. Once you're on the other side, you'll wonder why it took you so long to convert. The Millennials got it right about this part of the musical experience. :)
an Audio Research preamp in one of your systems?
I was first taken by the SP-3a in '74. Though I couldn't afford it at the time, the dealer lent me his over a weekend to compare with my H-K Citation 11. The SP-3a was so much more lifelike in top end resolution and soundstaging. I can still remember playing Do it Again by Steely Dan. The shakers and cymbals that open the piece just sounded real for the very first time.
They have been my choice for decades.
SP-6C: 1981 to 1998
SP-9MKII/III: 1998 to 2014
SP20: 2014 to ??
No, I haven't; although it has a terrific reputation. Sadly, I'm at the point, at 78.5, that my hearing is starting to go off in the highs. I'm a long ways from needing a hearing aid; but the upper treble is fading away. It's a lot of the reason I made the decision to get the second Adcom GTP-400 and quit there.
In one of those situations where classic measurements don't tell me anything, I've had a number of measured ruler flat frequency response preamps through here, and they all sounded and imaged differently. What I have not done, and probably should, is to run the preamps through an input/output linearity test. You put the input on the vertical axis of the oscilloscope, and the output into the horizontal axis, adjusting gain until the oscilloscope shows a 45 degree straight line. Any deviation from a single perfectly straight line shows the item under test is modifying the input. The sensitivity is such that if you can see a deviation, you generally can hear it. Phase shift changes the straight line to an ellipse, and amplitude non-linearities make the line curve. Distortion shows up as output along the X axis. Clipping shows up as vertical lines at the ends of the 45 degree line. You do need an oscilloscope that can do X-Y plotting and has a sharply defined trace, and when I bought mine, I made sure it could. That test dates back to the late 30's. It has fallen in disuse because of all the wonderful instruments we have that give numbers. The oscilloscope X-Y plot is subjective; but anecdotal evidence in both US and UK literature says it is sensitive and indicates things in combination that you can't easily measure together any other way, and does it on music. A lot of the test methods from the 30's and 40's are like that - they rely on cleverness as a substitute for measurements using precise instruments.
Jerry
Sadly, I'm at the point, at 78.5, that my hearing is starting to go off in the highs. I'm a long ways from needing a hearing aid; but the upper treble is fading away.
Those were simply impressions from the perspective of a teenager. :)
Today, I most appreciate their midrange focus, clarity, ability to project a wide and deep soundstage and render wide dynamics especially at the low end of the spectrum.
In one of those situations where classic measurements don't tell me anything...
Amen!
A lot of the test methods from the 30's and 40's are like that - they rely on cleverness as a substitute for measurements using precise instruments.
Or, simply the observations of those who are very familiar with the sound of live, unamplified music.
Or, simply the observations of those who are very familiar with the sound of live, unamplified music.
That works for setting up systems, or even voicing a speaker; but not so good as a diagnostic. You need something to tell you where to look. As in: why do two preamps that measure the same for frequency response and output impedance have noticeably different low bass with the same power amp and speakers? No problem hearing the difference; but I'd like to know why. If I knew why, maybe I could fix the weak one.
I'm sort of driven in that respect. Engineers generally want to know "how", and physicists generally want to know "why". Since I started as a physics major, maybe that's why I try to understand the why. I did it at work for years, too.
Jerry
As in: why do two preamps that measure the same for frequency response and output impedance have noticeably different low bass with the same power amp and speakers?...If I knew why, maybe I could fix the weak one.Very good question. From my experience with both tinkering with existing designs and comparing related ones, I'd venture to say the difference lies with the power supply. FWIW, the Pass Labs Xs preamp uses 100,000 uf of capacitance. :)
I find that "conventional wisdom" as to how stiff one should be seems to be underestimated using sine wave testing. The very best sounding gear I've heard employs heroic sized ones. :)
edit: I think I might have previously relayed this story, but I think it bears repeating. A Frank Van Alstine modified FET-5 preamp replaced my Citation 11 in 1976. Along with upgrading the quality of the passive parts and using LF356 op amps in place of LM301s, he greatly beefed up the power supply. That was also the era of "double Dyna 400" where he not only increased the number of output devices, but significantly boosted the size of the power supply via an external cabinet. As an inquisitive teenager passionate about sound quality, I followed his lead with an Audire One power amp acquired about the same time. It ran 20,000 uf of capacitance using ~ 50V rails for 100 watt/channel output. Julius Siknius' designs were clean, but I wanted more. So, I replaced the bridge with a 30A unit and added another 60,000 uF in an external cabinet. That increased the energy from 25 joules to 100 - which coincidentally was the value of my later 1981 Threshold Stasis 3 acquisition with comparable wattage.
Sonic difference? Much improved bass punch and dynamics with my Magnepan MG-II speakers. And, the music played on for about thirty seconds following power down. :)
Edits: 09/11/16 09/11/16
I've had similar improvements with beefed up; but less heroic power supplies. Adding extra caps in parallel increases the energy stored; but it also decreases the power supply impedance, allowing greater current flow rate. One of the design goals of the Adcom GTP-400, according to the designers, was to decrease the power supply impedance. The weaker sounding Rotel RTC940AX actually has 2x larger primary filter caps; but there is a lot of other circuitry between them and the output OP amps. The Adcom also uses OP amps; but there is nothing in the path between the filter caps and the OP amp. I may try adding some filter caps right at the output OP amp's power supply connections.
I also had a related experience with my Onkyo TX870 receiver, and an Onkyo A8190 integrated amp. The TX870 had very robust bass. It had a pair of 20,000 uF caps in the power supply, and in their literature, they touted the caps as having been selected for low ESR. The A8190 was from the same era; but used 12,000 uF caps and had an unusual "Real Phase Transformer" between the main power transformer and the rectifiers and caps. Both were nominally 100 W/ch; but the A8190 had noticeably less robust bass. So, on a hunch, I removed the Real Phase transformer, and the bass improved; but still not up to the TX870. Then, with the real phase transformer gone, there was room for another pair of caps of 8600 uF I had, so I put those in parallel with the 12,000 uF caps. Now the bass was quite close to the TX870. Next, I tried adding the real phase transformer to the TX870, and Poof!, the bass went wimpy.
The lesson I took from this little experiment was that the A8190's caps were too small, and lacked the special low ESR construction of the TX870's; and the extra windings of the real phase transformer added more series impedance to the power supply. Further, the added caps I put in were a low ESR type, so I don't know if it was the extra capacitance, or the low ESR, or both that did the trick. The NAD C350 I have also uses a pair of 22,000 uF caps; but again their literature talks about special low ESR types, and the C350 has a very solid low end, close to the bass power of the TX870.
Jerry
power supplies make a big difference in sound quality.
With my older Squeezebox Touch network player, I replaced the crappy SMPS with a linear (red box in pic) and enjoyed more resolution and clarity throughout the range.
With my current Sonore microRendu player (silver box at top center), I opted for a particularly stiff and quiet power supply for the same reason (black box at bottom right). Kinda dwarfs the player. :)
I am convinced that the overbuilt power supply is one of the reasons my Yamaha C2x sounds so good. This preamp is heavier than a few of my power amps!
Dave
When you think about it, devices that amplify are merely controls for the power supply. :)
Sure enough. EE courses used to actually teach that - I wonder if they still do? So much effort spent on signal path designs, and often the PS is neglected. Take a look at the Dynaco Stereo 70, for example. All kinds of mods to the PC board and different combinations of tubes; but the freak'n power transformer is undersized. That was also true of my Eico HF20 integrated amp. The power transformer got really hot in use; but that's another story.
Jerry
Take a look at the Dynaco Stereo 70, for example. All kinds of mods to the PC board and different combinations of tubes; but the freak'n power transformer is undersized.
FVA takes care of that today with his Ultravalve amp. :)
I still say you really should try a network player. You can get a wifi extender to wirelessly connect it to your stereo.
I use a netgear wireless router then use TP link extenders. Plug and play.
Sounds like you know what you like and you're sticking with it. Good for you. I'm pretty much in the same boat.
Took me a while to get here. Lots of false starts and detours along the way. This is by far my oldest hobby. It goes all the way back to 1953. So I've been at it for 63 years.
My other hobbies/interests have been building golf clubs, photography, and travel. Photography and travel go well together, so those are still active. I still enjoy music of various types, so listening goes on. And I pickup CD's at the library's annual book sale for $1; but I'm running out of room. And I've found that I can't build golf clubs as good as I can buy - that was not true even 12-15 years ago; but it is today. Do I still buy cameras? Yes, I do; digital cameras are still evolving.
Jerry
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