new 6c33 transformer

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E55l2

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new 6c33 transformer
« on: 8 May 2019, 06:31 pm »
I want to bring new live in an old 6c33 amp that i have. I used it for my esl speaker but now i want to use conventional 90dB sensitive speakers.

i just have some doubts wich impedance i should use for the 6c33. At the moment i have a 875 Ohm / 8 Ohm wich is pretty good i guess .

This is the frequency responce with a source impedance of 200 Ohm. Rdc primair is less then 10 Ohm and secondair 0.15 Ohms. Power 14W at 20Hz max.


Maybe a little fine tuning for the low frequency response because it's a bit to low (more core saturation)

Should i go for a lower primary impedance?

FullRangeMan

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Re: new 6c33 transformer
« Reply #1 on: 8 May 2019, 06:49 pm »
For this tube was used 500, 600 and 1k Ω, but in last years the market has settled on 600Ω, so 875Ω was in the mid of range. 500Ω will deliver more power and distortion/ harmonics.

Power 14W at 20Hz STM pretty good to a 90dB for a small room.
I should consider the core type and weight more important than the pri Z.

Please PM me with a price quote of a OPT like this: 600Ω, 30Wrms, C core, HiB 0.1mm, open frame.

E55l2

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Re: new 6c33 transformer
« Reply #2 on: 8 May 2019, 06:59 pm »
The core i use is a 600W C-core (600W in conventional 50Hz power transformer terms) I guess it weight about 6.5Kg but it could be a 100 gram more or less. The core is HiB quality.

I not use and are not interested in thinner core laminations for HiB. If you want thinner, use amorphous cores.

E55l2

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Re: new 6c33 transformer
« Reply #3 on: 8 May 2019, 07:05 pm »
For this tube was used 500, 600 and 1k Ω, but in last years the market has settled on 600Ω, so 875Ω was in the mid of range. 500Ω will deliver more power and distortion/ harmonics.

Power 14W at 20Hz STM pretty good to a 90dB for a small room.
I should consider the core type and weight more important than the pri Z.

Please PM me with a price quote of a OPT like this: 600Ω, 30Wrms, C core, HiB 0.1mm, open frame.

It makes no sense to ask for 30W 600 Ohm. It is never possible to get such power from a 6c33 and also you not say for wich frequency this power is.

The transformer i use 'can handle' easely 30W and more at a higher frequency (but that will never happen because the tube can not do this)

FullRangeMan

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Re: new 6c33 transformer
« Reply #4 on: 8 May 2019, 07:20 pm »
It makes no sense to ask for 30W 600 Ohm. It is never possible to get such power from a 6c33 and also you not say for wich frequency this power is.

The transformer i use 'can handle' easely 30W and more at a higher frequency (but that will never happen because the tube can not do this)
I mean say the 30W continuous for the OPT, the SE amp will run 10-12W.
Usually OTPs power are quoted in the bass, 30Wrms at 50Hz should be nice, the freq range I will let to your skills.

E55l2

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Re: new 6c33 transformer
« Reply #5 on: 8 May 2019, 07:24 pm »
i was more wondering about the sound. I like a clean open sound

FullRangeMan

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Re: new 6c33 transformer
« Reply #6 on: 8 May 2019, 07:57 pm »
i was more wondering about the sound. I like a clean open sound
Me too and add a detailed sound, so this looks a C core sound to me, the EI offer the old fashioned warm musical(little detailed) sound of tubes, which is also nice.