Adcom GFP-750 - Really disappointed...

audiocr381ve

acmf74 wrote: »

I recently got the gfp-750. I notice on my system using the passive mode the music sounds very "veiled" but on the active it sounds open a fuller. Is this normal or could this be just in my set-up?

Do you have the jumpers in place?

To me they sound really close. Both are definitely not veiled.

acmf74

I do have the jumpers..

This what it looks like

heiney9

acmf74 wrote: »

I recently got the gfp-750. I notice on my system using the passive mode the music sounds very "veiled" but on the active it sounds open a fuller. Is this normal or could this be just in my set-up?

Probably equal parts system, source material and what you are used to as far as sound. There are some recordings the passive mode just plain sounds bad. The passive is pretty much the recording completely naked, of course the source has a lot to do with this as well as cables. You could change your source and or cables and like the passive mode. Lots of variables and you need to choose which you like with what you currently have.

It's that elusive "system" synergy and what works for one person in their own rig, may not work exactly the same for another person in their rig. It appears you have the jumpers installed correctly.

H9

heiney9

When I'm not listening to tubes, I mostly run active. Passive tends to be a little too dry compared to what I'm used to. Although if I listen in passive for a few hours I can easily get used to that sound too.

H9

acmf74

Thanks h9

audiocr381ve

Guys, I'm really digging the new setup. I'm very content with the sound right now.

Breakdown:

In my room, with the extra power the bass became really boomy. Moving the speakers forward doesn't help me with WAF (wife approval factor). The boomy bass is something I'll have to live with for now, and it doesn't sound bad, it's just boomy. I did do an unorthodox inductor modification to my speakers which I know is contributing so I'm going to look into it. I used the Erse Super Q's at 17mh. The 2B stock inductors are 16mh so what I had to do is unwind and let my ears decide what sounded right. Problem is my ears aren't the best device for measurement. So I easily could have gone too far or not far enough, thus contributing to the boomyness with the extra power. Enough about that!

Preamp Addition:

This was the best purchase I've ever made, period. It made me rethink the ways in which I build a system. I'm the guy always taking the path of least resistance. I've always "cheaped out" on buying gear to hold me over until that day where money is less of an issue and I'd get to buy nice stuff. Well, I've been doing that for years. This time around I got sick of the way my system sounded and decided I need to do it right. With the help of many members, and tons of research, I decided I wanted the Stereophile Class A recommended Adcom preamp.

Sound:

This is the best way I can explain it. I work at home and have my desk not in front of, but off to the side of the system. I run music during the day as I work, and up until now the only piece(s) of gear that were able to really draw out my emotions as I work, almost in a distracting fashion, were the couple of vintage Marantz pieces I've owned. Mostly the 2245. Now this is not a scientific approach by any means, but it's an unmistakable feeling to me. I've had other pieces of gear that have come through that sound good in the background, but don't have that ability to draw me in like the vintage Marantz pieces did.

Well, with the addition of the new preamp, that unmistakable feeling of euphoria is there. I don't know how to explain it's sonic characteristics but I'll try. There is nothing that jumps out at me. It's just tighter and balanced. I wouldn't say warmer. Clarity and detail has really improved but not in a way that the top end sticks out. Everything is tighter. The Emotiva XDA-1 DAC/Preamp combo I had had tons of clarity, but the top end stuck out like a sore thumb and made everything else thin. The Marantz pieces made the music unbelievable warm and pleasant but it was sloppy. The GFP-750 is extremely pleasant to listen to, balanced, tight, and right. I hate to bring the wife into this but she was also blown away when she heard the system.

Amplifier Addition:

The B&K Reference 200.2 S2 came in yesterday. This one is a harder to explain. While the preamp was a dramatic difference, I didn't feel like the amp was. The low end got louder, but I didn't notice a huge difference between it and using the amp section of my Marantz 1150 integrated (75wpc). I found this strange. It's still very early though. I do want to try the balanced cables to see if it makes a bigger difference. Can anyone explain this?

Anyway, there ya go! Ha ha

tonyb

You maynot be needing that much of a draw in current for what your running, could be the difference between the amps. However, the B&K will rev up as the volume goes up or you introduce harder to drive speakers, where the marantz will just peter out.....make any sense ?

heiney9

audiocr381ve wrote: »

I'm very content with the sound right now.

You've said that every time during your last 10 gear swaps.

H9

audiocr381ve

heiney9 wrote: »

You've said that every time during your last 10 gear swaps.

H9

I'm a young man, 26, learning as I go my friend.

Btw, I just acquired a taste for good beer to. A year ago I wouldn't have known a Stone IPA from a Bud Light. Now I know. Make sense Brock?

steveinaz

audiocr381ve wrote: »

There is nothing that jumps out at me. It's just tighter and balanced. I wouldn't say warmer. Clarity and detail has really improved but not in a way that the top end sticks out. Everything is tighter.

What you're experiencing is better linearity. The sound just gets larger as volume increases, without pushing forward any particular frequency range. You've eliminated a ton of electronics, standing between you and the source. This is the "payday" with running passive.

This is why I went with the Placette. I wanted just volume control, and the methods Placette uses (IMO) is the most accurate way to do this. Not to mention the optimized load the amplifier "sees" from the passives output.

heiney9

audiocr381ve wrote: »

I'm a young man, 26, learning as I go my friend.

Btw, I just acquired a taste for good beer to. A year ago I wouldn't have known a Stone IPA from a Bud Light. Now I know. Make sense Brock?

Yep, just busting your balls a bit

audiocr381ve

heiney9 wrote: »

Yep, just busting your balls a bit

You're so good at it! :evil:

:cheesygrin:

audiocr381ve

steveinaz wrote: »

What you're experiencing is better linearity. The sound just gets larger as volume increases, without pushing forward any particular frequency range. You've eliminated a ton of electronics, standing between you and the source. This is the "payday" with running passive.

This is why I went with the Placette. I wanted just volume control, and the methods Placette uses (IMO) is the most accurate way to do this. Not to mention the optimized load the amplifier "sees" from the passives output.

That's good stuff. I've heard that word, linearity, used to describe gear before but never understood what it meant.

PreCd

I have a question while we are on the subject of jumpers and the 750. The GFP-565 originally came with jumpers but what were they used for? I have seen pictures of the inputs where the jumpers were installed. Should I have jumpers installed on mine somewhere? From memory it seems the processor in/outs were strapped. Something that has been on my mind for awhile now.

heiney9

Firstly, the straps used for the 565 are different. They are much larger and meant for std rca jacks. I looked at the manual at the Adcom site and it doesn't seem to mention anything, but I just skimmed it. If you don't have your manual I'd suggest you d'l it.

It was probably to keep extraneous noise out of the input/output.

H9

FTGV

PreCd wrote: »

I have a question while we are on the subject of jumpers and the 750. The GFP-565 originally came with jumpers but what were they used for? I have seen pictures of the inputs where the jumpers were installed. Should I have jumpers installed on mine somewhere? From memory it seems the processor in/outs were strapped. Something that has been on my mind for awhile now.

Assuming they linked between the RCA center pins they may have been for the processor loop so that signal would'nt drop out if processor switch was selected?

chandler9a

Thanks for the write up, sounds like this one was worth it.

Now for the beer issue... I'm a couple years ahead of you so I can warn you about those IPA's! They are heavenly and Stone is a good choice, now try the Bear Republic and have yourself a good time.:biggrin:

Stay away from Bud Light

audiocr381ve

chandler9a wrote: »

Thanks for the write up, sounds like this one was worth it.

Now for the beer issue... I'm a couple years ahead of you so I can warn you about those IPA's! They are heavenly and Stone is a good choice, now try the Bear Republic and have yourself a good time.:biggrin:

Stay away from Bud Light

Hehe. It's actually a new hobby of mine, trying beers that is. My brother is into brewing and San Diego is home of the micro brewery. He's the one that got me into it. My first real beer was a home brew a couple of years ago. Up until then, I didn't enjoy any type of alcohol.

Anyway, yes chandler, it's fantastic. Their is one on Audiogon for $650. I was lucky enough to find mine locally for $600. It's almost mint.

audiocr381ve

Noticed something strange a minute ago. Volume knob at 0% you can hear music coming through. Normal I think. Anyway, volume at 5%, and the balance is favoring the left speaker. At 10% it's perfectly balanced. Normal? If not what could be the problem? Could it be the speakers?

FTGV

audiocr381ve wrote: »

Anyway, volume at 5%, and the balance is favoring the left speaker. At 10% it's perfectly balanced. Normal? If not what could be the problem? Could it be the speakers?

With the exception of stepped attenuators tracking tolerances between the sections of a volume control will vary at different points over pots rotation so you could end up with a bias toward one side.Typically tracking tolerances between sections get tighter as you near the half rotation point or so.

Drenis

audiocr381ve wrote: »

Hehe. It's actually a new hobby of mine, trying beers that is.

I always try a new brew each time I hit the beer store. However I have to splurge on those current favorites every now and again. Really lovin' Sleemans right now.

Toolfan66

Funny mine favors the right speaker! As far as sound coming out with volume at zero mine does that in active mode..

audiocr381ve

FTGV wrote: »

With the exception of stepped attenuators tracking tolerances between the sections of a volume control will vary at different points over pots rotation so you could end up with a bias toward one side.Typically tracking tolerances between sections get tighter as you near the half rotation point or so.

aka no big deal?

Drenis, absolutely. We'd be good friends in real life.

rickrick37

I once used an Adcom multiple channel amp with not bad experience.

Joe08867

As far as tracking goes, I have seen in my travels with Adcom that if you turn it past what you want and then back down to it they seem to sync up better.

The zero volume and you hear something is sometimes normal. I have seen that a few times with certain pre's.

heiney9

Could be dirty, the Alps pot they use is a very nice one. I believe it;s sealed, but I could be mistaken.

This pre is not built like nor like any other Adcom pre, so issues with other Adcom pre's shouldn't carry over. A stepped attenuator would have been better and it would have raised the cost of the pre.

I never have turned my vol knob all the way down, I don't see the need for doing that. It has a mute switch, I leave the volume at whatever is normal for me and mute it if I don't want sound.

H9

cstmar01

when I was using the Adcom it was running balance and I never heard anything out of the speakers when it was all the way down. Super quiet pre.

My BAT even when turned down to 1 will still have sound coming out unless I turn it to 0 which is then muted. The Adcom is a good one to use. I really enjoyed it.

heiney9

The BAT has a digital volume control via a logic circuit, IIRC. The BAT uses a shunt volume control if my memory isn't flaking out on me.

The Adcom volume control is analog.

H9

CSM41

Heiney9,

Please explain the general differences that you hear in sound between when you run your Adcom preamp and when you run your tubed Dared preamp. I ask because I have a Dared, but am curious about the SS preamps out there. This one interests me.

heiney9

A tad more weight, images are carved out a little better, singers and midrange especially have a more liquid 3D quality, recording ambience details are a tad more noticeable. Overall the presentation from lower midrange to the top is much livelier and very 3D compared to the SS playback. Of course the magnitude is based heavily on the tubes you are using. Bass tends to drier and more controlled with the SS, sometimes that can be good depending on the recording.

These things are fairly subtle because the 750 is a really neutral and very good performer. But if I forget to flip the switch to put the tubes in the loop, after awhile of listening and being unaware the SS is playing I always feel like there is something missing, the presentation is just a tad drier and 2D comparatively. Almost everytime I notice this, the SS is playing not the tubes. There are also times when the tubes are brighter and/or have more detail than the SS. Again tube dependant.

I can sit in my listening position and with the volume set the same for each pre-amp can switch the Dared in and out by remote and do a side by side w/o ever moving. I did this a lot the first 3-4 months I had it and I have to say for two channel critical listening, tubes win most of the time.

My brother wonders why I even keep the 750 since almost all my listening is done with the Dared. For one when I watch movies I use the 750 and if I am streaming music from the SQB while doing other things around the house (non-critical listening). It saves wear and tear on the Dared and the tubes. Plus, I like the flexibility of my set-up and if the Dared ever had to go in for repair, I'd still have a stellar pre to listen to.

H9