PDA

View Full Version : 4350A setup sounds sluggish after move



j20056
02-19-2005, 11:47 AM
Hi. I'm new to this forum, but very excited to find other people fascinated by the 4350's. I have been happy with my setup for quite a while, in the US, but I recently moved to London, and I'm terribly disappointed by the current system performance, or lackthereof.
My setup:
* Pair of 4350A's with dual 2405's
* Active cross-over JBL 5234
* Low amp: MacIntosh MC7300
* High amp: MacIntosh MC7150
* PreAmp: MacIntosh C38
* CD Player: Wadia (forget the model - bought in 1995)

My problem:
* The power in the UK is 230V, my amps are 110V. I bought a stepdown tranformer, of capacity 3,000W. Generic brand, nothing special
* The new sound room in the house where I moved has carpet on the floor
* The sound is totally lame. The bass has absolutely no punch, it's like dead!
I don't know if it comes from the transformers, or the room (carpet), or some component wne bad (cross-over?).

Help appreciated!

scott fitlin
02-19-2005, 01:45 PM
Transformers tend to limit the current, and its effects are most noticeable exactly where you describe! THE BASS. This is the major reason i do not like power line conditioners, and transformers, they soften the sound, sometimes leaving the user with a system that has no spark.

However, since your in the U.K. what i would consider doing, if you can, is having your current gear set to operate on the U.K. voltage! This should not only restore your systems balls, but give them bigger ones then they had here in the U.S. as your amps will swing higher output voltage operating on 230v than they did on 120v! They also should run cooler as the amps only draw half the amperage at 230v as they do at 120v!

Everyone that I know ( pro sound ) that does or did shows in the U.K. always says the amps they use here with 120v kick ass when wired for 230v over there.

You need to find out if your electronics and amps can be wired for the U.K. voltage, most stuff can be, however there is some vintage gear that cant be! This, to me, will be your best bet!

Room acoustics might be having an effect as well, but I tend to think that step down transformer is bogging you down the most.

:)

Earl K
02-19-2005, 02:11 PM
Yes ,,, exactly - What Scott said .

( Convert it all to the better power )

( Even your crossover is convertable - download the manual from JBL )

:cheers:

j20056
02-19-2005, 02:52 PM
That's why I had bought a 3,000W transformer, which is 3x the nominal power. do you think it still would do what you desribed above?
I've been in contact with a company called Equitech. They claim that their balanced power conditioners, which are built to step-down from 230v to 110v would fix my problems. Another problem I did not mention is that I have low frequency hum in my recording gear, not the audiophile setup described above.
Does anyone know how good the Equitech products are?

scott fitlin
02-19-2005, 03:13 PM
Seems to be regarded well enough! BUT! IMHO, to really get the benefit of what Equitechs product does, still requires the HUGE wall cabinet they make!

Equitech works on the same principle as balanced audio signal lines, two legs of equal but opposite polarity cancel out noise! So th Equitech would take your 230 or 240v and step it down to 2 legs of AC, one +60v the other -60v, feeding your gear stable, clean 120v! They feature a toroidal transformer as well. I havent heard it for myself, but some I know says it works, and is good! The big wall cabinets are expensive though! I honestly feel it will be cheaper for you to convert your audio gear to 230v operation, and that I do know works!

Even though you have a transformer rated at 3000w, you have to understand that there is a lag time with the transformer, and when you hit a loud bass note, the amps draw instantaneous current, if the amps dont get that current at the precise time it tries to get it, you dont get the music with the power you should!

Again, amplifiers that sound great on 120v should actually sound better with 230v! This is what I would do! Unless your planning on moving back here soon!

:D

Chas
02-19-2005, 04:28 PM
Hi. * The bass has absolutely no punch, it's like dead!
I don't know if it comes from the transformers, or the room (carpet), or some component wne bad (cross-over?).

Help appreciated!

It sounds like you should check the polarity of the speaker cabling. You may have a reversal on one channel.

subwoof
02-19-2005, 08:48 PM
(1) The quote

"Even though you have a transformer rated at 3000w, you have to understand that there is a lag time with the transformer, and when you hit a loud bass note, the amps draw instantaneous current, if the amps dont get that current at the precise time it tries to get it, you dont get the music with the power you should!"

Is misleading since there already IS a transformer in the amplifier and also due to transformer core hysteresis AND the energy storage of the main capacitors, the "speed" of the transformer is of no issue. The amplifiers will NOT draw instantenous current. Hook up a current probe to the AC line and compare it in real time syncronized with the amplifiers output.

(2) The quote

"They also should run cooler as the amps only draw half the amperage at 230v as they do at 120v!"

makes NO sense since restrapping the power supply to the new voltage does NOT change the idle current ( bias ) or any other function of the amplifier's heat generating process.

BTW - the "kick ass" attribute is probably because when using amplifiers that are re-strapped to 230V losses on the neutral wire are eliminated. In addition at 230V the power loss for the same size wire at 115V is ONE QUARTER the amount ( I squared R )

So more power gets to the amplifiers + speakers and not just heating up the power cables...

Again it's basic physics.

sub

Mr. Widget
02-20-2005, 12:32 AM
Oh Subwoof! You probably don't like expensive speaker wire either! :uhmmmm:


Widget

subwoof
02-20-2005, 07:15 AM
To quote madeline kahn: It's twoo ! It's twoo!

My favorite is the oxygen free copper....what happens when you open the bag?

And the unique elements unobtanium and rarium. They rhyme with aquarium which means "sunk costs"

:cheers:

scott fitlin
02-21-2005, 12:50 PM
Check the power specs of most amps, and it shows that the same amps draw roughly half the amount of amperage running at 230v, as they do at 120v!

This information is available at www.crestaudio.com (http://www.crestaudio.com/), or www.crownaudio.com (http://www.crownaudio.com/)!

Amps sound better operating at 230v than on 120v, i have heard it for myself! They sound stronger!

And I HAVE had a current probe on my systems AC service, and it goes up and down, to the beat of the drum! It is not a steady current draw like a motor or lighting fixture, so therefore anything that that impedes the instantaneous current demands will affect performance! My systens idle current draw is 11 amps, and when playing music the meter can read anywhere from 12 amps. to 80 amps and everything in between, and it all happens fast. In a 30 second period you can monitor many different amounts of current draw.

Mr. Widget
02-21-2005, 01:10 PM
Check the power specs of most amps, and it shows that the same amps draw roughly half the amount of amperage running at 230v, as they do at 120v!


That is what our friend Georg Simon Ohm said almost two centuries ago. V=IR or I=V/R. :D

I= current
V= volts
R= resistance (input impedance)


Widget

subwoof
02-21-2005, 01:10 PM
Hey scotty - do the math.

Power = voltage X current

Faraday and Ohm proved it 150+ years ago. ( ohm's law ??? )

230 X 5 amps is the SAME as 115 X 10 amps

Half the current at TWICE the voltage is the *same* as 1X the current X 1X the voltage.

And BOTH configurations result in the SAME DC voltage **inside** the amplifier for it to work. And the same heat. And the same power. And the same speed. And the same sound.

The current probe ( tiny meter or whatever you have ) is NOT sychronized to the actual current draw ( It is designed to SLOW DOWN the visual response so a human eye can see it. ) unless you have a dual trace oscilloscope connected properly. And then you need to be trained to interpret / read the phase difference vs time when compared to the amplifier's output.

A basic course in electricity at any Comm college or boces will show you.

sub

Zilch
02-21-2005, 01:22 PM
However, we will all also agree that, given the same impedance in the supply circuit, the voltage drop will also be twice as much in the 120V vs. 240V supply.

No reasonably well designed amp is gonna give a whit about that, tho, unless the supply impedance is really bad. That's what voltage regulators and big storage capacitors in power supplies are all about.... :D

scott fitlin
02-21-2005, 01:35 PM
In theory what you say is correct, but in practice you can hear the differences!

Bass amps wired for 240v sound stronger than the same amp running on 120v, and do seem to run cooler!

As for my current probe, well, what your saying is true! The meter slows it down so we can SEE it, which means its actually faster than what we see! Instantaneous! So, the less devices between the wall and my amps the better!

Now, if all things are equal, and make no difference, WHY are their so many AC devices on the market?

Some years back I had a situation in here with my AC! We had installed a new service for the system! I wasnt here when the electrician installed the cable run, and he opted to use unshielded Greenfield instead of Pipe! It was easier for him to work with, but all I knew was my system sounded very different, bad to be exact, and the bottom was nowhere to be found! After much reading up about things, I finally decided that this flexible conduit without shielding containing the Hot, neutral, and ground wire was the culprit! Inductive reactance, and EMF every time I turned the system on! Needless to say, everyone thought I was nutz, even my father thought I had lost it! Well, I got another electrician in here, we took out the greenfield, replaced it with standard aluminum pipe suited for the wire sizes being used, and reconnected the service this way! When I turned the system on, you should have seen the looks on everyones faces! What a difference it made! The BASS was kickin like a mule, the highs and mids soundes far cleaner, and the preamp controls seemed much more responsive, didnt have to push as hard to get what I wanted! We all heard it, no one really knew WHY this was, but we knew it WAS!

Running amps on 230v sounds different ( IMHO ) than running the same amps on 120v! I think it can be better, but thats just me! You might feel otherwise!

:)

Zilch
02-21-2005, 01:59 PM
Not arguin' with Scotty. Nope.

I wanna ride the bumper cars when the time comes.... :D

[And I want mine runnin' under MAXIMUM power! Heh, heh.]

scott fitlin
02-21-2005, 02:21 PM
Not arguin' with Scotty. Nope.

I wanna ride the bumper cars when the time comes.... :D

[And I want them under MAXIMUM power! Heh, heh.]:bouncy: Max power, speed 3, 100VDC, Pretty good too!

Years ago had 4 and 5, tooo fast, 105vdc and 110vdc! When I was a kid, a bad little bastard, I knocked many a grown men OUT of the cars, and no one could catch me! Still cant! :bouncy:

Mr. Widget
02-21-2005, 02:23 PM
I wanna ride the bumper cars when the time comes.... :D

[And I want mine runnin' under MAXIMUM power! Heh, heh.]


Me too! Me too! :applaud:


Widget

scott fitlin
02-21-2005, 02:30 PM
Me too! Me too! :applaud:


WidgetC`mon, and after we get some Nathans Hot Dogs! :thmbsup: