Elrog 300B vs Takatsuki 300B tubes

Al,
If you have 200 amp service in your home, do you use all of the current that your electrical service box offers? Of course not. It's there to insure capacity. Also, many 5 volt filament transformers for output tubes provide in excess of the 1 1/4 amps that a traditional 300b tube will draw.

Right now I happen to be looking at a Hashimoto power transformer that has a 5 volt/3 amp winding for each channel of a 300b amplifier. The tube doesn't need that amount of current, but will function just fine connected to it. The output tube draws what it needs from the current reservoir. The same goes for a rectifier tube. With rectifier tubes, you control the amount of B+ you have in your circuit by deciding on your choice of rectifier tubes.

Many people talk about how one rectifier tube sounds over another, but the real reason for this is the amount of B+ that has been added(or reduced)into the equation. This causes the output tube to work at a higher or lower anode voltage and that of course will influence the sound of what is being heard. Hope this helps.

Best,

George

Based on what George just said, I suppose the answer to my question is a yes.

Thanks, George. I don't doubt that what you are saying is correct in most and perhaps nearly all cases. But without knowing the DC resistance or low frequency impedance of the filament winding of the particular transformer (which would enable calculation of the voltage that is dropped across it for a given current draw), and perhaps also the +/- tolerance on the transformer's turns ratio, I'm not certain we can say that for sure. Although I will state that I don't have a particular feel for what those numbers are likely to be for the kinds of power transformers that are used in audio components such as these.

Again, see the statement by Matthias of Elrog that I quoted in my first post dated yesterday (10-28-15).

10-28-15: Dracule1
So as far as Elrog 300B in Lampizator Golden Gate DAC is concerned, a rectifier that draws 2A/5V is fine (assuming GG DAC has a separate 3A winding for rectifier tube)?

10-29-15: Dracule1
Based on what George just said, I suppose the answer to my question is a yes.

Yes, certainly as far as the 300B is concerned, given George's point about the separate filament windings. And most likely as far as the rectifier is concerned, although per my comments above I for one am not sure we can say that with certainty.

FWIW, IMO, etc.

Best regards,
-- Al

It occurs to me that I should perhaps add some clarification to Matthias' statement I referred to just above, which I quoted in my first post of yesterday. That statement was:

If an EML 300B XLS is the right choice we have 1.5A heater current at 5V. There is no voltage regulation. A transformer a rectifier bridge and a CLC only. May be the XLS is underheated (so I hope) ore all other (right) 300B are overheated, because they draw 1.2A (some russians and chinese 1.25A)only. This would result a heater voltage above 5V...not so good for any 300B and very bad for an Elrog 300B, because the use of thoriated tungsten for filaments. Higher heater voltage will result a (much) higher anode current and a much lower lifetime...

What he is saying is that if the power transformer's filament winding is designed to provide exactly 5 volts to a 300B which draws 1.5 amps, if a different 300B which draws 1.2 amps is substituted the voltage applied to that 300B will be higher than 5 volts, to a degree that might be harmful over time. The reason for that increase in voltage is that the reduced current draw will result in a reduction in the voltage that is dropped across the resistance of the filament winding.

Note also that he is referring to a difference in current draw of only 0.3 amps.

In principle similar considerations may come into play when a rectifier rated at 2 amps is substituted for one rated at 3 amps. However I suspect that the sensitivity to filament voltage increases of the rectifiers being discussed is considerably less than the corresponding sensitivity of a 300B.

Best regards,
-- Al

I have measured this in my amp. Since my EML 300b XLS filaments draw 1.5 amps I have to adjust the dropping resistors so I still get 5 volts because voltage gets pulled below 5 volts. Other 300b tubes that draw 1.2 amps makes the voltage rise above 5 volts making me re adjust the dropping resistors. It's ohms law in practice. I heat my filaments with a/c. Jet