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Old 14th November 2016, 08:59 AM   #721
AndrewT is offline AndrewT  Scotland
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Location: Scottish Borders
getting 6Vac from an 18Vdc supply will right at the limit of visible clipping.
But long before you get there, there is an increase in distortion. Initially it's mostly second harmonic and because it's a Follower without global feedback it can sound quite acceptable.
Because of that increasing distortion with signal level, many advise a maximum signal level of ~ half the clipping level, i.e. <3Vac from an 18Vdc supply. This fits well with most CDP and other high level sources which top out at around 2Vac to 2.5Vac.
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Old 15th November 2016, 04:48 PM   #722
kpsthakur is offline kpsthakur  India
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Thanks Andrew, meanwhile I am also looking at possibilities to replace 2SK170 as I have exhausted all I had. I read in one of the discussions we could use BF862 as a possible replacement...can anyone on this forum guide me if this has been attempted before for B1 buffer within this forum, also if I need to make mods to the existing design from Papa Pass

Last edited by kpsthakur; 15th November 2016 at 04:49 PM. Reason: spellcheck
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Old 16th November 2016, 07:26 AM   #723
AndrewT is offline AndrewT  Scotland
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Check power dissipation.
Read Juma's Threads on using the BF862.
It may be advisable to reduce voltage slightly for the BF862. DCB1 runs @ 20Vdc, B1 runs at 18Vdc, BF862 maybe 16Vdc?
Alternatively adding a cascode to each BF862 could be a good direction to go.
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Old 9th March 2018, 09:34 PM   #724
Syl20m is offline Syl20m  Finland
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B1 builders thread
Hi All,

I just finnished solder the PCB...
was considering to use a HP laptop power brick 18,5V 3,5A
any feedback, experience to share using that ?
thanks in advance
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Old 10th March 2018, 03:54 PM   #725
bassnkeys is offline bassnkeys  United States
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Join Date: Feb 2011
Location: MN
Default Power Supply

That laptop supply will be plenty. Put a meter on it to see what it actually puts out. Anything in that range should be fine but I've seen some that vary widely from what is stated. I've had excellent service from an old Panasonic phone supply for a B1 I built. Rock solid.
I wouldn't worry too much about being a bit over or under. I have another B1 build using a supply that runs at 21V. Sounds fantastic. I think the B1 circuit is pretty tolerant.
DB in MN
25f and light snow at 11am
P.S.
The B1 will run on a pair of series 9v batteries. That's a good way to test. Very low amperage means very low damage risk if something isn't quite correct.

Last edited by bassnkeys; 10th March 2018 at 04:06 PM.
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Old 10th March 2018, 04:19 PM   #726
Russellc is offline Russellc  United States
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B1 builders thread
Quote:
Originally Posted by Syl20m View Post
Hi All,

I just finnished solder the PCB...
was considering to use a HP laptop power brick 18,5V 3,5A
any feedback, experience to share using that ?
thanks in advance
I used such a power supply for a while. It functioned, but I noticed an improvement with the simple regulated unit 6L6 used in his build thread.

Russellc
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Old 12th March 2018, 06:01 PM   #727
Syl20m is offline Syl20m  Finland
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Join Date: Jul 2015
B1 builders thread
Hi All,

i am thinking to add :
input selector,
balance Pot,
Pot attenuator,

any obvious mistake in my sketch?
thank in advance guys!
Attached Images
File Type: png Balance + attenuator.png (87.0 KB, 78 views)
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Old 12th March 2018, 06:17 PM   #728
ColinA123 is offline ColinA123  United Kingdom
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Quote:
Originally Posted by Syl20m View Post
Hi All,

i am thinking to add :
input selector,
balance Pot,
Pot attenuator,
K.I.S.S.
Just use separate left and right attenuators,
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Old 12th March 2018, 06:45 PM   #729
Syl20m is offline Syl20m  Finland
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Join Date: Jul 2015
B1 builders thread
Hi Colin,

That is what I did so far for my first build!
But this is not easy, and needs adjustments every time increasing or lowering the attenuation,
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