[Ray Samuels]

Hi Lisa...
You do not have to be sorry at all, I am sorry that my clarification of the matter was not put in the right manner words wise, which makes it sound harsh, I apologise for that.
Cheers.
Ray Samuels

 

[ppl]

This is what i use at 260 MAh thay are half the capacity of a typical alkiline
http://www.onlybatteries.com/showite...temID=12297.64

 

[martycat]

Thanks Ray! So the battery voltage doesn't really matter to the sound quality, am I right?

 

[Ray Samuels]

Quote:

Originally Posted by martycat Thanks Ray! So the battery voltage doesn't really matter to the sound quality, am I right?

That is correct...
Ray Samuels

 

[greenhorn]

I read the following in the user manual of the Porta Corda II amplifier:

"The circuitry inside needs very little current and the amplifier runs for approximately 100 hrs on a single 9V battery. [...] To save batteries and to increase sound quality at home an external powersupply can be connected with a supply voltage up to 28V DC."

So a higher voltage is supposed to increase sound quality - or not?

 

[Lisa]

Quote:

Originally Posted by Ray Samuels Hi Lisa... You do not have to be sorry at all, I am sorry that my clarification of the matter was not put in the right manner words wise, which makes it sound harsh, I apologise for that. Cheers. Ray Samuels

Thanks, that's nice of you to say. But also not necessary. I understand that you just wanted things to be perfectly clear about the SR-71.

 

[GainHead]

I think the SR-71 uses a center-tap of the two batteries to create a "real" ground - the same as the Grado RA-1 design. So whatever batteries you do use, you will want to make sure that the batteries are charged to the same voltage and discharge at the same rate.

 

[martycat]

Quote:

So whatever batteries you do use, you will want to make sure that the batteries are charged to the same voltage and discharge at the same rate.

I just found a strange issue about the batteries with my SR-71. The pair of 8.4V battery suddenly distort severely with the amp, it's their first hold of charge so I'm not sure if it's the matter of the unmatched condition. I changed the batteries and the amp works properly again. After several hours, I gave the 2 8.4V a try again... they worked well for the first several minutes but again they distort like crazy...

I'm trying the 8.4Vs now, the right channel distort and then suddenly fade out... oh... it comes back now... but both channels are about 50% much quiet...

Is it normal...???

 

[Lisa]

Quote:

Originally Posted by martycat I just found a strange issue about the batteries with my SR-71. The pair of 8.4V battery suddenly distort severely with the amp, it's their first hold of charge so I'm not sure if it's the matter of the unmatched condition. I changed the batteries and the amp works properly again. After several hours, I gave the 2 8.4V a try again... they worked well for the first several minutes but again they distort like crazy... I'm trying the 8.4Vs now, the right channel distort and then suddenly fade out... oh... it comes back now... but both channels are about 50% much quiet... Is it normal...???

Yes that's normal.
The voltage of NiMH drops suddenly when they are fully depleted. Causing the amp to sound like this. This just means that you need to charge them.

 

[GainHead]

Quote:

Originally Posted by Lisa Yes that's normal. The voltage of NiMH drops suddenly when they are fully depleted. Causing the amp to sound like this. This just means that you need to charge them.

Either that or one battery is discharged more than the other and causing an offset that exceeds the capability of the opamps.

 

[martycat]

Thanks all!

 

[greenhorn]

So the opinions of two well respected amp builders are perfectly in opposition.

When speaking about 9V powered amps, one of them says that "the battery voltage doesn't really matter to the sound quality" while the other says that "to increase sound quality at home an external powersupply can be connected with a supply voltage up to 28V DC".

I am unexperienced in electronics => I am lost and I would be really grateful if somebody will show me the light

...

 

[dougbrad81]

my expirence with the ray samuels xp-7 is that with alkaline batteries, it doesn't affect the sound in anyway even when it drops to 3.5v. this is not the case with my old meta42. the sound clearly detoriates when the voltage drops. that's why i use alkalines for the xp-7 and rechargeables for the meta42. what Mr. Samuels is saying applies to his amps, and not for battery powered amps in general.

 

[Earwax]

Quote:

Originally Posted by greenhorn So the opinions of two well respected amp builders are perfectly in opposition. When speaking about 9V powered amps, one of them says that "the battery voltage doesn't really matter to the sound quality" while the other says that "to increase sound quality at home an external powersupply can be connected with a supply voltage up to 28V DC". I am unexperienced in electronics => I am lost and I would be really grateful if somebody will show me the light ...

It's not necessarily much of a conflict since they are two different designs with different components. Whatever opamps Ray is using, they must sound good all thru the range that 2 x 9Vs can supply. Jan has a design that he feels benefits from increased voltage. Different designs, different opamps, different voltage.

 

[greenhorn]

I see. Got it. Thanks!