Thx
Thank yiu
I have to find a schematic how to wire it. What rating should I look for? 0.7kv or so?
Thank yiu
I have to find a schematic how to wire it. What rating should I look for? 0.7kv or so?
You said power draw was 450W, so 4A on the primary, which means 4A through the secondary of the buck transformer, so 50VA. Don't go huge on the bucking transformer, it doesn't do anything helpful.
Thx
Hi
I have to confess I don’t know how to calculate volt-amperes (((
So a 0.25 kv should be plenty enough?
Thx
Hi
I have to confess I don’t know how to calculate volt-amperes (((
So a 0.25 kv should be plenty enough?
Thx
50VA is a transformer capacity rating. 0.25kv would be a 250V transformer.
P-8658: Jameco Reliapro : Power Transformer 12V@4A 117VAC Wire Leads : Power Supplies & Wall Adapters
Thank you
Would 4A be enough?
I found this on Ebay, seems cheap and simple:
Hevi-Duty HS19A250 Transformer Primary: 120/240 Secondary: .250 KVA 1PH 12/24VAC | eBay
AC voltage in US
I measured B+ today 520v, with my apt ac voltage at 123. I think it’s a bit tough on 6550... Am I wrong?
I measured B+ today 520v, with my apt ac voltage at 123. I think it’s a bit tough on 6550... Am I wrong?
Resistor
Thank you Tony
Where would I put those resistors? I assume we are talking about inside the amp? Which would certainly make everything cleaner. I think amp has four separate high voltage lines for each group of three tubes. I guess I need to put for dropping resistors between transformer windings and posts on PC board. Measure the current and calculate the value, and power.
Thank you Tony
Where would I put those resistors? I assume we are talking about inside the amp? Which would certainly make everything cleaner. I think amp has four separate high voltage lines for each group of three tubes. I guess I need to put for dropping resistors between transformer windings and posts on PC board. Measure the current and calculate the value, and power.
I'm running 6P3S at 560V right now... I wouldn't worry about the voltage, just make sure it's within the design maximum Pd and you should be good.
It'll work, but it's 5 times the needed size... Here's one at DigiKey for less money... TCT50-03E07K Triad Magnetics | Transformers | DigiKey
No, it's not enough - you'd be running it at 100% of its rated capacity - you need to derate at least 25% and I prefer 100% in an application like this which is why I suggested 100va.
I recommend this:
AS-1209 - 100VA 9V Transformer - AnTek Products Corp
It's $22
Our nominal line voltage was 120V when this amplifier was made but I believe it was tapped for 115 - 117V so a 9V transformer would put you in the ballpark.
I recommend this:
AS-1209 - 100VA 9V Transformer - AnTek Products Corp
It's $22
Our nominal line voltage was 120V when this amplifier was made but I believe it was tapped for 115 - 117V so a 9V transformer would put you in the ballpark.
The amplifier is class AB so you would just introduce signal dependent sag just like a guitar amplifier. This isn't something I'd do, secondly by the time there is meaningful voltage drop across that resistor the power dissipation may be a problem in the space available.
A bucking transformer is the right way to go.
A bucking transformer is the right way to go.
i have done this many times with no noticeable degradations, 4.7 ohms can be replaced with 47 ohms,😱
if you measure the voltage drops across the 4.7 ohms resistor, you will know the load current, then you can measure the voltage to ground on either side of the 4.7 ohm resistor..you can then calculate a new value of resistor based on your target new output voltage, ohm's law really...
you can get the new wattage of the new resistor, voltage x current, if you get something like 2 watts, i will use a 10 watt resistor..
the new resistor and the filter caps form a low frequency zero, just make sure that the new time constant gives you a frequency of about 5hz which i believe is more than enough..
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you can put in a new resistor in place of the 4.7 ohms, mount the new resistor so that it is 10mm or more off the board...