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Old 30th April 2010, 02:56 PM   #11
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Quote:
Originally Posted by dupyv View Post
Kofi,

I second Ian444's advice to check out the later BabyHuey variant with fixed
bias and mosfet followers. I checked this version out in a test-bed and found it
to be more effortless & dynamic in the bass. Hence i'm building my 2nd BabyHuey according to the fixed bias version.

The original BabyHuey is my "daily-driver", it's an excellent choice too, it's
a bit simpler to build.
You won't be disappointed with any of the BabyHuey variants, as Gingertube said: It's simple to build but hard to match.

Kind regards,

Yves
Yes!

Well, I can't really explore fixed bias at this time as I'm making this for a friend who wants a no-fiddle amp and would like to tube roll at some point...

Quote:
Originally Posted by adamus View Post
another huey, marvellous.

My huey constantly impresses those who get a listen.

when picking parts, i found that the sound is senstive to the bypass caps in the el84 cathodes. do spend here.

I would also say, the 6p14p-ev (ev is important) are the best output tubes you can buy under 20. Bloody marvellous.
I'm rockin' a Mundorf MKP for this position (you're talking about the .22uF snubber on the electrolytic, yes?). Any other mid-priced cap you'd recommend?

Kofi
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Old 30th April 2010, 03:01 PM   #12
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Also, any reason (other than cost) not to go for choke in the PS. IT makes it so much easier to tweak the B+ and leads to a lovely silent supply (with fostex 95db/w i have zero hum with a choke input).
There is no reason other than cost. I am using two separate supplies and two additional chokes would likely put the project out of reach cost-wise. I could, of course, switch to a single PSU for the entire project. Would a 200mA total current draw for both sides be correct?

Kofi
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Old 30th April 2010, 03:01 PM   #13
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Hi, i am actually talking about the larger electrolytics needed.

The smaller bypass (film) makes a difference, but i played arounnd with the electrolytics and they have a huge impact. I settled on 1000uf blackgates. Silimics were good too.

I tried some horrors there, some killed any enjoyment from the amp.
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Old 30th April 2010, 03:03 PM   #14
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Originally Posted by Kofi Annan View Post
There is no reason other than cost. I am using two separate supplies and two additional chokes would likely put the project out of reach cost-wise. I could, of course, switch to a single PSU for the entire project. Would a 200mA total current draw for both sides be correct?

Kofi
40ma or so for each el84 + not a lot at all for the rest, so yes, 200ma is about right for the whole amp.

I used a 15h hammond choke. pros and cons to both methods. You dual mono design would theoretically provide better channel seperation.
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Old 30th April 2010, 03:04 PM   #15
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Originally Posted by adamus View Post
40ma or so for each el84 + not a lot at all for the rest, so yes, 200ma is about right for the whole amp.

I used a 15h hammond choke. pros and cons to both methods. You dual mono design would theoretically provide better channel seperation.
Would you be willing to share your supply design?
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Old 30th April 2010, 03:13 PM   #16
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no probs.

hammond 370hx (275-0-275 @2ooma) > full wave recitified but stealth diodes > 8.4u obbligato film cap > 15h hammond choke > 220uf > 20r per channel > 220uf per channel (bypassed by obbligato 0.22uf film).

it simulates as slightly overshooting on turn on, but in reality i dont see that, and it looks good on the scope. Its probably overkill, the old mullard PP amps had no where near the capacitance shown here and a smaller choke, but it doesnt hum at all.

layout shown here, choke at the front right, excuse the wonky tubes, that was an old pic and they are now straight. also please excuse the sex in the city boxset, thats the wife's.

Click the image to open in full size.

my thoughts on the input valves. The ecc803s are ok, but from experience the triode sections can be very mismatched. If you can get hold of a pair, the techtube 12ax7 are superb but out of production now. The tjfullmusic 12ax7's also sound very good and wont break the bank.

Last edited by adamus; 30th April 2010 at 03:20 PM.
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Old 30th April 2010, 04:45 PM   #17
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Quote:
Originally Posted by adamus View Post
no probs.

hammond 370hx (275-0-275 @2ooma) > full wave recitified but stealth diodes > 8.4u obbligato film cap > 15h hammond choke > 220uf > 20r per channel > 220uf per channel (bypassed by obbligato 0.22uf film).

it simulates as slightly overshooting on turn on, but in reality i dont see that, and it looks good on the scope. Its probably overkill, the old mullard PP amps had no where near the capacitance shown here and a smaller choke, but it doesnt hum at all.

Click the image to open in full size.

my thoughts on the input valves. The ecc803s are ok, but from experience the triode sections can be very mismatched. If you can get hold of a pair, the techtube 12ax7 are superb but out of production now. The tjfullmusic 12ax7's also sound very good and wont break the bank.
Sounds like an excellent PSU, but unfortunately its out of my range for the project. I'd like to get a choke in there, but I could only realistically afford an 8H / 100mA Hammond for each side. Would I be able to add that to the original Gingertube supply? If so, would I need to add this between the 220uF and the 47R?

The $95 per pair 12AX7s from TJ are out of reach as well, unfortunately. I think these ideas will all work as upgrades, however...

Also, what are you using for OPTs?

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please excuse the sex in the city boxset, thats the wife's.
Errr. OK... Sure...

Kofi
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Old 30th April 2010, 04:58 PM   #18
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Originally Posted by adamus View Post
I would also say, the 6p14p-ev (ev is important) are the best output tubes you can buy under 20. Bloody marvellous.
6p14p-ER can now also be had for USD 24/quad on eBay (twice the life of -EV and much thicker glass)
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Old 30th April 2010, 04:59 PM   #19
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Quote:
Originally Posted by Kofi Annan View Post
Sounds like an excellent PSU, but unfortunately its out of my range for the project. I'd like to get a choke in there, but I could only realistically afford an 8H / 100mA Hammond for each side. Would I be able to add that to the original Gingertube supply? If so, would I need to add this between the 220uF and the 47R?

The $95 per pair 12AX7s from TJ are out of reach as well, unfortunately. I think these ideas will all work as upgrades, however...

Also, what are you using for OPTs?



Errr. OK... Sure...

Kofi
i used hammond opt too.

If i lived in the us i would try edcor, they look very good value indeed.
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Old 30th April 2010, 05:39 PM   #20
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Quote:
Originally Posted by Kofi Annan View Post
There is no reason other than cost. I am using two separate supplies and two additional chokes would likely put the project out of reach cost-wise. I could, of course, switch to a single PSU for the entire project. Would a 200mA total current draw for both sides be correct?
I'm not sure I understand the two supplies, or the voltage doubler. A single Hammond 270HX with a CLC supply and a choke (Hammond 159S) will be easier, and better, and probably cheaper too -- you can buy the pair for under $100.
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