Tube advice needed

ben62670
ben62670 Posts: 15,969
edited November 2009 in Electronics
OK I built my tube grounded grid pre, and I am having a minor issue. It plays fine when I turn it up, but when the volume is real low it distorts. The heaters are 12.16vdc regulated. This is almost a half volt low. Is this a concern? Also the output impedance is 100k is this too high?
Thanks
Ben
Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
Thanks
Ben
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  • Systems
    Systems Posts: 14,873
    edited November 2009
    ben62670 wrote: »
    Also the output impedance is 100k is this too high?
    Yes big time:eek:Is there a 100k pot at the output?
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  • ben62670
    ben62670 Posts: 15,969
    edited November 2009
    Oops input impedance on my pot. For testing purposes I have the pot after the pre.
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • Systems
    Systems Posts: 14,873
    edited November 2009
    I would connect a pot of that value at the input side.
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  • ben62670
    ben62670 Posts: 15,969
    edited November 2009
    I will, but right now I am in testing phase. I have a lot of work to get everything in one case. The tube/passive/active pre with a DAC and an XO is almost complete:) Very very happy here:):):)
    I bought an Adcom surround pre for the case to stuff this stuff inside. I want the tubes sticking out the top. The only clue that it isn't an old POC surround processor;)
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • ben62670
    ben62670 Posts: 15,969
    edited November 2009
    I so wish you could hear it. The snap of the drums, and the rim shots are freaken fantastic! Seriously if you ever are down stop and stay!
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • Systems
    Systems Posts: 14,873
    edited November 2009
    ben62670 wrote: »
    I so wish you could hear it. The snap of the drums, and the rim shots are freaken fantastic!
    Good to hear your liking it.You might want to try a stepped attenuator instead of the pot.
    I recently replaced the Alps in my pre with a 20k Valab series stepped att .It is an Asian sourced clone of the megabuck DACT unit's and built to a high standard ( sells for a mere $20 ish epay).Compared to the Alps it has perfect channel balance regardless of setting,increased detail was apparent and the noise floor was lowered.IMO an inexpensive but very worthwhile upgrade/tweak.

    I may get another for the direct coupled Pass B1 I'm building.
    Seriously if you ever are down stop and stay!
    Thanks for the offer,though the temp's that far south might be too hot for us igloo dweller types to handle.
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