- Posted by john2 on April 15, 2004 at 12:43:02
Any thoughts on using LL1663PP for parallel pair of EL84 in ultralinear.
I thought of using a PSU with 1638 as 4H 500ma after 2 GZ34 or should I use a GZ34 and 10H 200ma for each channel? Can I use two GZ34 like this, into one choke? Should I use them as single diodes or sum them? The circuit uses one ecc88 per channel.
Follow Ups:
- Re: parallel EL84 into LL1663PP - john2 14:57:57 04/15/04
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- In Reply to: parallel EL84 into LL1663PP posted by john2 on April 15, 2004 at 12:43:02:
thanks,
Does the fact that the primary is 5k or 5.5k make any difference. The original circuit probably used 8k for two EL84, 4k with parallel tubes. Do I need to modify the circuit?
- Re: parallel EL84 into LL1663PP - KevinC 15:06:05 04/15/04
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- In Reply to: Re: parallel EL84 into LL1663PP posted by john2 on April 15, 2004 at 14:57:57:
I doubt if it makes a significant sonic difference. The higher impedance (5K vs. 4K) will reduce power somewhat and distortion, too. Not to worry!
What does the input circuit design look like?
- Re: parallel EL84 into LL1663PP - john2 15:20:15 04/15/04
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- In Reply to: Re: parallel EL84 into LL1663PP posted by KevinC on April 15, 2004 at 15:06:05:
It is the Morgan Jones from his book Valve Amplifiers. Single 6dj8. He specs a 285v regulated supply for the tube. Looks to be the same (well similar) circuit that diyparadiso.com use for their double EL84 amp- simple driver concertina phase splitter.
- Re: parallel EL84 into LL1663PP - john2 15:20:15 04/15/04
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- Re: parallel EL84 into LL1663PP - KevinC 15:06:05 04/15/04
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- Re: parallel EL84 into LL1663PP - KevinC 13:43:05 04/15/04
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- In Reply to: parallel EL84 into LL1663PP posted by john2 on April 15, 2004 at 12:43:02:
The use of the LL1663/PP is appropriate for a push-pull parallel EL84 amp if you have higher impedance (8 ohms) speakers. If you have lower impedance speakers (5-6 ohms), you should use the LL1682/PP.
If you have the 5V 4A filament supply necessary, you can do it either way. The separate recitifer/choke scenario is more expensive. You can parallel both sections of one GZ34 and use it as one diode and do the same for the other for the combined channel PS. I might be tempted to separate the supplies by using separate diodes and chokes for each channel, but then I sell chokes, don't I? ;=))
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