Hi,
I've just finished my first tube amp. It's got one PCL86 per channel giving an output of around 4 W.
My question is this: is it allright to run the filaments at 14.2 V even if in the data sheet states 13.3 V?
Shall i expect problems?
Should i use a voltage regulator?
Not an expert but its sound makes very happy.
Thanks in advance.
Cheers
Alk
Advice: don't dread low wattage amps. I don't have efficient speakers -below 90 dB- and i am afraid to push it to its limit...sure neighbours would call the police. I am not exaggerating. You are allright if you live in a house i don't.
Bloody apartments.
I've just finished my first tube amp. It's got one PCL86 per channel giving an output of around 4 W.
My question is this: is it allright to run the filaments at 14.2 V even if in the data sheet states 13.3 V?
Shall i expect problems?
Should i use a voltage regulator?
Not an expert but its sound makes very happy.
Thanks in advance.
Cheers
Alk
Advice: don't dread low wattage amps. I don't have efficient speakers -below 90 dB- and i am afraid to push it to its limit...sure neighbours would call the police. I am not exaggerating. You are allright if you live in a house i don't.
Bloody apartments.
Hi,
The datasheet should state 13V (AC or DC) at 300mA.
The P series are normally used in series string hook up with other valves, the voltage isn't too critical but the current should be held constant.
So ideally you should use a regulator a voltage regultor followed by one with current set to 300mA.
Something like this should work for DC heaters:
Cheers,😉
The datasheet should state 13V (AC or DC) at 300mA.
The P series are normally used in series string hook up with other valves, the voltage isn't too critical but the current should be held constant.
So ideally you should use a regulator a voltage regultor followed by one with current set to 300mA.
Something like this should work for DC heaters:
Cheers,😉
Attachments
DDDac has a nice pcb for sale that holds two voltage & current reg pairs. Voltage/current reg
As Frank says - Pseries valves really appreciate this.
...says James running some P series valves at 250mA and not caring... but they are in a guitar amp high gain stage (PC86) and they sound nicer at that current ( sorry 316a!)
ciao
James
As Frank says - Pseries valves really appreciate this.
...says James running some P series valves at 250mA and not caring... but they are in a guitar amp high gain stage (PC86) and they sound nicer at that current ( sorry 316a!)
ciao
James
Thanks for the replies....forgot to mention that i'm using AC.... i am having very low hum so don't need DC plus i've read somewhere that using AC for the filaments sounds better and that DC was a necessary evil only for preamps...any truth in this?
Cheers😀
Cheers😀
I think i should give all the information. I went cheap and for the power supply i'm using two 15-0-15 2A transformers connected to each other so i have 220v before rectifying and secondaries 15v . I only needed one 15V but those were at hand so the PCL86 are not in series for i have power to spare.
Comes to mind if it would better- to avoid long cables- to run them from the same power ....what would be best?
Happy with the hum level anyway. In fact my initial post was because i was worry for the lifetime of the valves.
Cheers
Frank, thanks for the schematic.
Comes to mind if it would better- to avoid long cables- to run them from the same power ....what would be best?
Happy with the hum level anyway. In fact my initial post was because i was worry for the lifetime of the valves.
Cheers
Frank, thanks for the schematic.
Hi,
If you want to reduce the voltage further I'd put a 1 Ohm resistor in each leg of the AC heater feed.
P series valves aren't too critical about the voltage as they were meant to be put in series with others to form a series string.
As long as the total voltage supplied added up and each had 300mA to burn away it usually worked fine.
Cheers,😉
If you want to reduce the voltage further I'd put a 1 Ohm resistor in each leg of the AC heater feed.
P series valves aren't too critical about the voltage as they were meant to be put in series with others to form a series string.
As long as the total voltage supplied added up and each had 300mA to burn away it usually worked fine.
Cheers,😉
Thanks Frank, i thought about the resistors but wasn't sure...in the amp i used kiwames with good results so i guess i should use those in the filaments supply with no noise problem.....
One more thing...even if i have no chance of knowing how short is my amp in some areas -my previous amp was a Sony solid state
and , of course, this one sounds marvellous to me- i do think that if it souds so good it must be
because of its design for my construction and layout were far from perfect. White Loftin design has turned out to be a great choice for a beginner like me.
Cheers
Alk
One more thing...even if i have no chance of knowing how short is my amp in some areas -my previous amp was a Sony solid state
and , of course, this one sounds marvellous to me- i do think that if it souds so good it must bebecause of its design for my construction and layout were far from perfect. White Loftin design has turned out to be a great choice for a beginner like me.
Cheers
Alk
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