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May 25, 2019, 04:13:06 am

Author Topic: Low frequency extention problem  (Read 458 times)

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Offline Simonatsea

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Low frequency extention problem
« on: May 04, 2018, 06:17:27 pm »
Hello,

I have aquired a Seduction with C4S. It appears to be built well. It have amazing detail reproduction and is relitevly low noise. I am impressed with its sound however it is clearly lacking in the mid to low frequency region. I have compared it to rather high end phono stages, it seems to have them beat or matched on the high frequency detail retrieval but definetly lacks in the mid to low ranges. To you point that something sounds wrong. Both channels seem equal in their frequency response.
I have played around with higher end coupling and bypass capacitors, this only seemed to better the high frequency detail and speed. I have also increased the output capacitor value to 1uf from .47uf hoping to get a little more low frequency but the results were negligable.
The wiring in the power supply appears to be solid core silver in teflon tubing. Could this cause the lack of low frequency?

I have also not tried any other tubes, currently using some jan green labeled 6dj8’s

Thanks in advance

Simon

Offline Paul Joppa

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Re: Low frequency extention problem
« Reply #1 on: May 04, 2018, 06:41:21 pm »
It seems likely there is a problem in the operation or wiring. At least, you describe what I have heard when the equalization is off! The best approach is to first make sure the circuit is working correctly. Do you have the manual, and are you able to make the resistance and voltage checks?
Paul Joppa

Offline Simonatsea

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Re: Low frequency extention problem
« Reply #2 on: May 05, 2018, 03:36:12 am »
I do not have a manual, as seen in other forum threads, I should request it from bottlehead directly.

Offline Paul Birkeland

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Re: Low frequency extention problem
« Reply #3 on: May 07, 2018, 09:21:05 am »
I'm also available to handle repairs on legacy kits if you need a second set of eyes to look at it.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Simonatsea

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Re: Low frequency extention problem
« Reply #4 on: May 10, 2018, 07:35:36 pm »
Thankyou. I should have the manual shortly. Do you know where I should start trouble shooting? As I said both channels appear to be equally as lean. It has great detail retrieval but the bottom end just isnt there when compared to my other phono pres

Offline Paul Birkeland

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Re: Low frequency extention problem
« Reply #5 on: May 11, 2018, 04:51:01 am »
Voltage checks are a good place to start.

The manual is also a little sparse on pictures, but a lack of LF extension that isn't accompanied by troubling voltages would lead me to look for a missing or poorly connected set of EQ caps.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man