2. amps-preamps
  3. 1132627794

Major help needed in Input and output impeadance..

Okay, so if you have a 10 kohm or 10,000 ohm input in amplifier terms, what are the parameters for the output on the preamp? I see anything ranging from 50 ohm to 600 ohm in preamps outputs. And see many amplifiers from 10 kohm , 20 kohm, 30 kohm, 50 kohm etc... I know there is a rule of thumb but what is weird Is most of the manufactures I see building amps with 10 kohm up to like 50 kohm are building preamps with only about 50 ohm outputs.... nothing near what some other manufactures use between 220 ohm to about 750 ohm.

I will have a 600 ohm out pre soon and my amps are only 10,000 ohm inputs. so what does this mean? it almost seems that the 600 ohm may not be compatible in looking at the matching most manufactures use as they are all much lower output impeadance in general vs. my preamp, so what happens, I get less gain, more noise, what can be a problem if you have mismatched impeadances between these two components? Or is all this irrelevant and I just need to get the preamp and listen and not worry about it? But I swear I read something about this topic at some time and really want to make sure I know what I am doing.

Thanks, Ps. in my post I did use K- for increments of 1000 if anybody got confused when I wrote out the whole number and then started using the abbreviation with 'K'
matrix
jeffreybehr's avatar
jeffreybehr
805 posts
 
Matrix, the 1:20 ratio is just a rule of thumb, and I suppose there are almost as many systems with ratios under that number that operate and sound great as there are as systems with ratios over that number that don't operate perfectly and don't sound great. I suppose your 1:17 is marginal.

I can't do more than speculate from here, but if I owned and loved those pieces and could configure my system with SHORT ICs and long speakercables, that's what I'd do.

How long are the interconnects?
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matrix OP
305 posts
 
They are 6 ft... could be possibly shortened a bit maybe to 4 ft if necessary, but they go to mono blocks so got lower margin for adjustment for the distance.
matrix OP
305 posts
 
Okay guys, heres what I found

Balanced audio tech in fact builds a preamp with 750 ohm outputs, it states on there chart it is recommended not to go below 10,000 kohm amp... they have models capable of even driving some rediculosly designed amps with 3,000 ohm inputs but need to use their Optional "Bat Pak"

I also called McCormack Audio, I do not own their equipment, however they have there Flagship amplifier the DNA-500 at 10,000 ohm input... It is in the words of their engineers that Anything over 10 times your preamp impeadance is perfectly fine, So if it is 600 ohm its good to even drive a 6,000 ohm impeadance Amplifier, which is rare to find, but they even went on to say the most Weird and hard to drive amp they have seen to date(and he could not remember the name) was at 2,000 ohm input and they believe the only preamps they would have available to drive it is from their sister company Conrad Johnson with something in the 50 ohm output range...

So from what I found is 1:20 ratio is not the rule it is 1:10 I guess, which now thinking back I have heard multiples of 10 were always the rule? So I guess we are okay, Thanks guys it was good info.
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