Adcom GFP-750 just came in, low volume

thsmith

What is the input impedence of your AMP ?

heiney9

thsmith wrote: »

maybe is has a 250k ohm volume control, may have been replaced, just guessing but that would not explain the passive and active volume being the same.

In the manual is there options you can set inside that explain this ?

I had a 750 for a while but do not remember much about it.

Active has 2 or more times the gain, no options to set. Explain what? Passive has no gain, zero, so if the volume control is in the same position in active, when you switch to passive it's quieter so you increase the output gain by turning the vol knob up. Pretty simple, no settings, etc.

H9

heiney9

thsmith wrote: »

What is the input impedence of your AMP ?

It's not the amp, the 555 should mate very well.

To the OP, listening at 12-1:00 on the dial is extremely high for the active stage unless the previous owner had a difficult to drive amp. When I start to hit 11-12 on the dial I'm over 95dB in my room.

H9

thsmith

Some preamps have gain settings or straps inside H9.

Like I said I do not remember much about the 750.

Did find the manual and there is no mention of settings under the hood.

Just trying to help the OP.

Some of us do have a clue.

chandler9a

This is what I was thinking, I have never played any pre that high before. I mean it sounds great but the gain thing is just weird to me, maybe its a cheap fix, I don't know.

We will see what happens.

heiney9

Does the remote volume control work? If it does, those are pricey to replace so a cheap fix might not be the reason. Anything is possible with used gear. He may have gotten it that way if he isn't the original owner and never knew something was wrong.

Tracy, I realize what you are saying, but that would have been the first thing mentioned if that was the case. Sorry if my response seemed salty, wasn't meant to be.

H9

FTGV

A couple of points to remember when comparing with other preamps ,the Adcom (when in active mode) has less gain than typical and ofcourse it has no gain thus functions merely as an attenuator in passive mode.At lower volume settings it's probable that the levels will be very similar between active and passive modes.

thsmith

That was my point about a 250k pot, oem may have failed a new one was swapped in. Such a bummer to have a new piece of equipment and not be able to enjoy or have doubts.

heiney9

FTGV wrote: »

A couple of points to remember when comparing with other preamps ,the Adcom (when in active mode) has less gain than typical and ofcourse it has no gain thus functions merely as an attenuator in passive mode.At lower volume settings it's probable that the levels will be very similar between active and passive modes.

In my rig and in my experience I have noticed a drop in volume between passive and active no matter what the vol pot is set at.

YMMV

H9

P.s. Purely speculation on my part, but many people complain the passive/active control isn't also on the remote, my feeling is if one accidentally switched from passive to active from the remote, it's possible to damage speakers or gear since I have noticed such a wide gap in the output between the two settings.

FTGV

thsmith wrote: »

That was my point about a 250k pot, oem may have failed a new one was swapped in.

Highly unlikley,it's a 4 ganged 2k motorized Alps.Can you say scarce and spendy!

thsmith

FTGV wrote: »

Highly unlikley,it's a 4 ganged 2k motorized Alps.Can you say scarse and spendy!

I was not clear, replacement may not have been Alps or even motorized, H9 question about remote working might help determine that.

FTGV

I suspect it's just a matter of the Adcom having lower gain than the NAD it's being compared to.At least -3 db less than is typical(in active mode).

heiney9

FTGV wrote: »

I suspect it's just a matter of the Adcom having lower gain than the NAD it's being compared to.

Very good point.

H9

SCompRacer

Have you got a volt meter? Maybe measure the output voltage on the active output, meter set to low scale, AC. Compare it to specs or someone elses.

thsmith

FTGV wrote: »

I suspect it's just a matter of the Adcom having lower gain than the NAD it's being compared to.At least -3 db less than is typical(in active mode).

I would agree if it were not for the 3 clock volume setting.

scottyboy76

Just noticed the thread, i bought a 750 here, also noticed the volume difference between this and my old adcom that tnhndyman now owns.

So much so, im thinking of buying a 555 to replace my present adcom gfa 5400 amp (200 watts compared to present 125).

I dont usually listen at high volumes anymore, but when i really want it, its just not there with 125 watts.

Dont get me wrong, the sound quality is far superior to my old pre, just needs a more powerful amp.

Also, for anyone who remembers the volume problem when adjusting with the remote, I paid audiolab 50 bucks to check it out, they had it hooked up for 10 days, couldnt get it to recreate the runaway volume with remote, brought it home, on the third try, the volume ran away, Needless to say, i presently do not use a remote with my preamp.

I might someday get a harmony remote and try that.

heiney9

scottyboy76 wrote: »

Just noticed the thread, i bought a 750 here, also noticed the volume difference between this and my old adcom that tnhndyman now owns.

So much so, im thinking of buying a 555 to replace my present adcom gfa 5400 amp (200 watts compared to present 125).

I dont usually listen at high volumes anymore, but when i really want it, its just not there with 125 watts.

Dont get me wrong, the sound quality is far superior to my old pre, just needs a more powerful amp.

Also, for anyone who remembers the volume problem when adjusting with the remote, I paid audiolab 50 bucks to check it out, they had it hooked up for 10 days, couldnt get it to recreate the runaway volume with remote, brought it home, on the third try, the volume ran away, Needless to say, i presently do not use a remote with my preamp.

I might someday get a harmony remote and try that.

Hmmmm.....I have 30wpc. How does mine even emit sound according to your analogy? How "powerful" the amp is has nothing to do with it really.

FTGV

scottyboy76 wrote: »

Just noticed the thread, i bought a 750 here, also noticed the volume difference between this and my old adcom that tnhndyman now owns.

So much so, im thinking of buying a 555 to replace my present adcom gfa 5400 amp (200 watts compared to present 125).

I dont usually listen at high volumes anymore, but when i really want it, its just not there with 125 watts.

Unless the input sensitivities of the amps differ substantially the results will be the same with either.(As in same output level with same volume control setting.)

organ

scottyboy76 wrote: »

Just noticed the thread, i bought a 750 here, also noticed the volume difference between this and my old adcom that tnhndyman now owns.

So much so, im thinking of buying a 555 to replace my present adcom gfa 5400 amp (200 watts compared to present 125).

I dont usually listen at high volumes anymore, but when i really want it, its just not there with 125 watts.

What speakers are you using? If the amps are similar in design, the extra 75 watts won't do much at all. You would need 250 watts just to increase your volume by 3db.

scottyboy76

Not really an expert on these matters, I appreciate the info ftgv, you may have saved me some cash.

Im listening to some recently recapped dcm time windows 3s organ, they can handle 300 watts, and i always thought the higher the wattage amp, the more volume, with other components affecting that.

By the way organ, how do i get to vaporizer island, and is it worth the trip?

never traveled that way myself

scottyboy76

BTW, I have to admit i kinda miss tone controls, Iknow, many think they are evil, but.

FTGV

scottyboy76 wrote: »

Not really an expert on these matters, I appreciate the info ftgv, you may have saved me some cash.

Im listening to some recently recapped dcm time windows 3s organ, they can handle 300 watts, and i always thought the higher the wattage amp, the more volume, with other components affecting that.

f

I'll clarify my point.While yes the 250watt amp will have higher output capability both amplifiers might put out similar power given the same input voltage(same setting on preamp volume).As an example both might only put out 100watts given 1 volt of input from the preamp.

scottyboy76 wrote: »

BTW, I have to admit i kinda miss tone controls, Iknow, many think they are evil, but.

Looks like you need some time in the naughty chair.:cheesygrin:

organ

scottyboy76 wrote: »

Im listening to some recently recapped dcm time windows 3s organ, they can handle 300 watts, and i always thought the higher the wattage amp, the more volume, with other components affecting that.

By the way organ, how do i get to vaporizer island, and is it worth the trip?

never traveled that way myself

Very unique speakers you have there. I don't have experience with it but found the specs... Specifications:
# Dimensions:36"H x 14 3/4"W x 11 3/4"D
# Weight:32 Pounds
# Power Requirements:10 Watts Minimum per channel 89 dB/watt at one meter;200 Watts Maximum
# Impedance:5 Ohms minimum/6-8 Ohms nominal
# Frequency Range:25Hz to 18 kHz
# Dispersion:180 degrees horizontal/60 degrees vertical.

It looks like your Adcom should be good for them. 89db sensitivity and 5 ohm minimal. So they're not that demanding.
I"m thinking they weren't made to "rock out and party" like some speakers. My Polk RT1000p towers are great but they can't rock hard like my Klipsch. They just have a limit as to how much dynamics and overall spl they can pull off.

Nah, a vaporizer island could be anywhere where there is a vaporizer lol... http://www.storz-bickel.com/vaporizer/volcano-vaporization-system.html

scottyboy76

Ok organ, now the big question, how about a link for something to go in the volcano.

organ

scottyboy76

And just to be clear, i have read some of the threads where people misplace jumpers, or for some other reason, their 750s are seriously muffled, noisy etc.

That is most def. not the case, this can get to 92 dec. at about 1 oclock, but we all know there are those nights.

And by the way, the time windows are lovely since the caps have settled in, love the open sound, imo, a lot of bang for the buck, could be a bit more bass in general, but that is also depending on whats being played, at times they can reach down pretty well.

organ

That sounds great. A lot of folks get nice improvements with better caps in their x-overs.
When you say you're not getting enough when you want to crank it, what kind of SPL are we talking about?
If you like to crank it a lot, you can always look into horn loaded speakers and rotate when you're in the mood for loud music.

To the OP,
If the seller is not willing to deal with you anymore, you can contact Adcom and ask for a repair center near you. They can tell you right away if there is something wrong with the volume because they repair this stuff all the time. They can also give you an estimate as to how much repairs (if any are needed) will cost. If there is something wrong with the unit, and the seller won't do anything, you will lose a bit of cash.
I just find it strange that you need to turn the knob that high to get any usable output.
Check the jumper position like Scottyboy mentioned.

chandler9a

I Know this pre's gain is different than many others I have owned so that could just be what I am not used to. I put it on my fathers system and I still had to turn it up past half way to get it to make some noise. It sounded great but I am just not used to turning it up that high.

The seller insists there is nothing wrong with it and he could be right, I just might get it checked out at some point to make sure.
You are right H9, you just never know with used gear.

heiney9

1/2 way in active mode seems very high, but all rigs are different. I was listening last night noting where the volume control on mine is. For nomal loud listening it's between 10 and 11:00. 12:00 would blow me out of the room. I would suggest if you are going to get it checked out do it before the opportunity to file a claim against the seller has past.

In my experience with the 750 in the beginning is it's the type of piece that sneaks up on you. At first listen it might not sound all that different but as you continue to listen to your favorite, familiar tracks over a couple weeks, it hits you how good it really sounds. Smooth, open, effortless, dynamic etc.

H9

chandler9a

Yea, it is definitely not too loud at 12:00. Just comfortable to listen to at the most.

I'll have to take a look around to see where the closest Adcom repair shop is in Central, NY. If anybody has any suggestion, please let me know.

All rigs are different, but not this much. I mean, its not like I'm using a walkman as a source and computer speakers haha.