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Pete B's Achievements
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Dear Pete B,
I am writing because some of my internet searches over the years have taken me to your posts on the Classic Speaker Pages forums. Thank you for your contributions.
My interest is in building a pair of speakers similar the the EPI 150 or Genesis Model II using parts available from Human Speakers (Human Models 81 and 81-10, respectively). I would build the EPI 150/Model 81 to the internal volume of 1.5 ft3 and the Genesis II/Model 81-10 to 1.8 ft3 as recommended by Huw Powell of Human Speakers.
https://www.humanspeakers.com/diy/81.htm
https://www.humanspeakers.com/diy/8110.htm
I understand this question is subjective but I would like to know which of the above you would recommend based on the following:
1. My room size is 10’ x 15’.
2. My amplifier is conservatively rated at 40wpc/8 ohms and I doubt I would ever listen above 85dB.
3. I want speakers for two-channel music only without a subwoofer. However I do appreciate low bass as intended.
4. My music choice is primarily progressive of classic rock from the 70’s and 80’s such as Yes, Genesis and Mike Oldfield.
Thank you in advance for your help!
Rick H
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Hi Pete,
I just did a recap of Dynaco a25's which included your 1uF mod. Luckily I have two pairs so could A/B with the an original crossover. As expected there is a very nice increase in the top end and the addition of "air" as you say. The original cap was 4.7uF. It measured 5.2uF when removed. I replaced it with parallel 3.3uF and 1.8 uF Jantzen Standard-Z caps.
Would you have a moment to quickly explain the effect of the 1uF cap? My electronics is getting better but I'd like to hear your thoughts.
Thanks very much!
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The tweeter level control provides some resistive attenuation. Remember/consider that a cap passes
high frequencies and the addition of the cap provides a path for the highest frequencies to in a sense
bypass the resistive loss. It can only lift the same amount that the resistors are attenuating so as you
turn up the level the effect will be less. You can bring the HF bypass to pass at a lower frequency by
increasing the size of the cap.
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Thanks so much for your reply Pete. I'm only seeing this now after a recent post I made concerning AR-5's. Yes, I've been reading about the bypass cap and this was a very obvious sonic change...not to mention the new 5uF film cap I also installed. I did read that some suggested the 1uF should have been .1uF and the "." was possibly omitted in the document. Perhaps you could confirm.
Thanks again.
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I don't know where anyone made that comment but they are wrong it is 1.0 uF.
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