G-PULTEC problems, please help!

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1wildthing

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Jan 27, 2021
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thanks guys once again for your precious help, I’ve finished the build. Everything seems to work as expected but I’ve noticed a small roll-off in low frequencies (35-40hz) even when eq is bypassed in comparison to the dry signal.
Is this a normal behavior or is depending on something I did wrong?
 

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gyraf

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Being a soft bypass, where amplifier is still in circuit, this is probably normal to some degree. Also, overload characteristics and such are still in play in bypass..

/Jakob E.
 

1wildthing

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Being a soft bypass, where amplifier is still in circuit, this is probably normal to some degree. Also, overload characteristics and such are still in play in bypass..

/Jakob E.
Thanks! However the overall sound is amazing. Great piece of gear. I'm already thinking of building a second one for a stereo pair.
 

Bonsaimaster

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Apr 17, 2013
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Dear All,

I am using a G-Pultec as a gain stage for a Classi PEQ Eq board. I have not gotten the parts for the EQ board. However in the bypass )gain stage only I have high gain output. I have Carnhill 10K:10K on the input and Carnhill 9600k:600 on the output. Any way to decrease the gain to utility gain? Thx!
 

gyraf

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..the GPultec requires around 20dB of makeup gain - so the gain stage delivers approximately this - and it's not meant for variable gain.

If you need it at unity gain, you can possibly wire it up with some feedback, as it's an inverting amplifier

/Jakob E.

edit: Here's a good article describing the idea behind the SRPP gain/output stage used here: http://www.valvewizard.co.uk/SRPP_Blencowe.pdf
 

Nyquist

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Apr 23, 2014
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Hello peoples. I'm staring to gather components to build a pair of these EQ's. Question on transformer if I may.
I have some KT transformers. the spec are as follows

1:1
600:600ohm
DC resistance 15ohms
Max output +18 dBv into 600ohm load
20-20Khz 0.1dB 600ohm

Would they be suitable for SRPP build? Thanks in advance.
 
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