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Old 25th October 2010, 03:27 AM   #901
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Thanks gingertube, now I understand ;-) I leant something today, ergo, today is a good day...
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Old 15th November 2010, 11:08 AM   #902
booth is offline booth  United Kingdom
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Hi I am also a newbie and have been reading this thread for sometime. I began my build of the original version of the baby huey about a month ago and am very keen to see how good it sounds.

My question is about the Bias for the EL84 tubes. As it is unclear to me from the schematic which way round the Bias is connected. I've been doing a bit of reading to see if I can work it out.

From what I can gather the Cathode usually has a negative Bias but the grid should be negative with respect to the cathode. Otherwise there will be grid current. However, if grid is too negative wrt cathode (several volts) you come to the situation called cut-off where no current flows to plate or screen grid. In this circuit the grid is at 0 volts if no grid current is flowing. So does this mean I want the cathode to be positive? To have the Bias connected with the positive side to the Tubes?
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Old 15th November 2010, 12:45 PM   #903
adamus is offline adamus  United Kingdom
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EL84 Amp - Baby Huey

cathode pin to the top of the bias block, ground the bottom.
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Old 15th November 2010, 03:35 PM   #904
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I've looked at the schematic of the bias blocks many a time and have only just noticed that the Blackgate 470uf 50v electrolytic cap hasn't got it's polarity marked.

Top plate ( cathode pin side ) +

Bottom plate ( ground side ) -
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Old 25th November 2010, 12:47 PM   #905
CSlee is offline CSlee  United Kingdom
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I am currently mid Baby Huey build and am searching this vast thread for any posts of speaker choice. It seems that some are using the uFonkens....

What are people using for their Baby Hueys?

Being a novice DIYer im looking for plans for something to compliment my Baby Huey when it is finished.

Charlie
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Old 25th November 2010, 01:22 PM   #906
booth is offline booth  United Kingdom
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Thanks for the help guys.

Im using Fostex full range units in some home made horn loaded cabinets. Ordered them from Wilmslow Audio in Leicester. Not tested them with the Huey yet as its not quite finished - but they sound great with my Rodgers Cadet.

Photos of my Build: Baby Huey EL84 Valve Amp | Facebook
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Old 25th November 2010, 02:52 PM   #907
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Booth,

That's a well thought out build, lots of useful photos for other builders - congrats.....

Charlie,

I'm using Monitor audio bronze, and sometimes some old Kef Coda 2's but would like to upgrade.

I was thinking of starting a separate thread to find out what speakers are attached to other peoples Baby Hueys, or indeed any pp EL84 amp, will wait and see the response here .:



Ps Wouldn't mind what Gingertubes got

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Old 28th November 2010, 10:05 AM   #908
CSlee is offline CSlee  United Kingdom
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Just a quicky,

My heater windings have a CT, if i connect the 2 100ohm resistors from each side to that, do I still need to connect that to ground? Or should I ignore it and follow the schematic?

Charlie
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Old 28th November 2010, 10:15 AM   #909
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Quote:
Originally Posted by Charlie Slee View Post
Just a quicky,

My heater windings have a CT, if i connect the 2 100ohm resistors from each side to that, do I still need to connect that to ground? Or should I ignore it and follow the schematic?

Charlie
You should leave out the 2 100ohm resistors and connect the CT to ground
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Old 28th November 2010, 10:35 AM   #910
CSlee is offline CSlee  United Kingdom
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thanks hidnplayr
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