Go Back   Home > Forums > Blogs
Reload this Page Bas Horneman's diyAudio.com blog

Old

Another baby step with the LM3886...

Posted 24th November 2009 at 08:14 PM by Bas Horneman (Bas Horneman's diyAudio.com blog)
Click the image to open in full size....
Attached Thumbnails
Click image for larger version Name: ikeagainclone.jpg Views: 2979 Size: 101.3 KB ID: 58   Click image for larger version Name: wiring1.jpg Views: 14415 Size: 162.9 KB ID: 59  
Bas Horneman's Avatar
diyAudio Moderator Emeritus
Posted in Gainclones
Views 5467 Comments 2 Bas Horneman is offline
Old

It will take a while before the Baby Huey is done...

Posted 23rd November 2009 at 10:52 PM by Bas Horneman (Bas Horneman's diyAudio.com blog)
Updated 24th November 2009 at 05:01 PM by Bas Horneman
therefore in between I'll be posting progress on my LM3886 "gainclone"

I soldered the boards a long looong time ago. So no pictures. And I don't think anyone would want to see these boards soldered part by part. pcb's are boring in that way.

The build will be quick and dirty. But still something I could "live" with. Hopefully.
Attached Thumbnails
Click image for larger version Name: one.jpg Views: 724 Size: 105.9 KB ID: 57  
Bas Horneman's Avatar
diyAudio Moderator Emeritus
Posted in Gainclones
Views 1867 Comments 3 Bas Horneman is offline
Old

Delivery

Posted 20th November 2009 at 07:48 PM by Bas Horneman (Bas Horneman's diyAudio.com blog)
Look what the mailman/woman dropped at my casa.

A matched quartet of GM70's (Almost ashamed at how little I paid for them) GM70's are for a SE GM70 amp with MQ parafeed iron.

And the 500R trimpots and 0,22uF caps for the Baby Huey.

Click the image to open in full size.
Attached Thumbnails
Click image for larger version Name: delivered.jpg Views: 8252 Size: 94.8 KB ID: 52  
Bas Horneman's Avatar
diyAudio Moderator Emeritus
Posted in Buying
Views 788 Comments 0 Bas Horneman is offline
Old

Ordered 500R pots for the driver stage.

Posted 18th November 2009 at 09:27 AM by Bas Horneman (Bas Horneman's diyAudio.com blog)
And while I was at it I saw some 0,22uF Epcos MKV from the same seller. The Epcos will do duty as coupling cap, as I've seen good reports (anecdotal) on them.

I asked Ian (gingertube) what the 470R resistors were for. Because I figured the CCS would take care of everything of the balance.

Here was his answer:
Quote:
The 1K pot is to set balance in the diff amp. The resistance in the triode cathode degenerates the tube gm (Ia/Vgk). Sweeping the pot wiper from side to side varies the amount of degeneration on each of the 2 triodes until they match. This is the minimum distortion condition for the diff amp. As we don't want to throw away gm un-necessarily we don't want those resistance values too high - just high enough to be able to adjust for matching behavior.
For a random sampling of 12AX7 and ECC803S that I had, 1K was too much, 100R was'nt quite enough so I dropped the 470R on each side of the 1K pot which effectively makes that pot about
...
Continue reading...
Attached Thumbnails
Click image for larger version Name: 500r.jpg Views: 516 Size: 17.0 KB ID: 49   Click image for larger version Name: epcos.jpg Views: 521 Size: 12.0 KB ID: 50   Click image for larger version Name: cepcos.jpg Views: 351 Size: 11.3 KB ID: 51  
Bas Horneman's Avatar
diyAudio Moderator Emeritus
Posted in Buying
Views 738 Comments 0 Bas Horneman is offline
Old

Slowly but surely making progress

Posted 16th November 2009 at 10:36 PM by Bas Horneman (Bas Horneman's diyAudio.com blog)
I have used a diy fluid for drilling for the first time. Used bicycle chain oil...water and detergent. Quite happy with it. Drilled the largest hole yet. And it looked almost professional.

Also a photo of the oak enclosure after it was treated with boiled linseed oil. The oil makes the oak enclosure look a lot better, it really brings out the grain. As usual I don't have "before" pictures to show the difference. (the pictures below had a partial coat already)

I'm not sure what to seal the wood with. Suggestions are welcome. Right now I'm thinking about shellac.
Attached Thumbnails
Click image for larger version Name: moreholes.jpg Views: 414 Size: 68.3 KB ID: 47   Click image for larger version Name: grain.jpg Views: 391 Size: 35.7 KB ID: 48  
Bas Horneman's Avatar
diyAudio Moderator Emeritus
Posted in Building
Views 647 Comments 0 Bas Horneman is offline
Old

Output tubes's CCS's (bias blocks) completed.

Posted 15th November 2009 at 12:14 AM by Bas Horneman (Bas Horneman's diyAudio.com blog)
sans bypass cap.

Measure 380mV accross a 10R resistors. Therefore the CCS is set to 38mA.
Attached Thumbnails
Click image for larger version Name: ccs38mA.jpg Views: 448 Size: 121.1 KB ID: 35   Click image for larger version Name: 2ccs.jpg Views: 813 Size: 97.9 KB ID: 38   Click image for larger version Name: ccs_output.jpg Views: 691 Size: 24.9 KB ID: 39  
Bas Horneman's Avatar
diyAudio Moderator Emeritus
Posted in Building
Views 802 Comments 0 Bas Horneman is offline
Old

First holes have been drilled...

Posted 19th October 2009 at 08:07 PM by Bas Horneman (Bas Horneman's diyAudio.com blog)
Mock up pictures. The wooden "boxes" are from Ikea and will cover the output transformers. The single power transformer shown will be put under the chassis.
Attached Thumbnails
Click image for larger version Name: bh1.jpg Views: 4099 Size: 60.7 KB ID: 27   Click image for larger version Name: bh2.jpg Views: 1298 Size: 67.7 KB ID: 28  
Bas Horneman's Avatar
diyAudio Moderator Emeritus
Posted in Building
Views 1962 Comments 2 Bas Horneman is offline
Old

Building the Baby Huey EL84 PP

Posted 19th October 2009 at 03:08 PM by Bas Horneman (Bas Horneman's diyAudio.com blog)
As a way to kick off my project. I decided to pour the Baby Huey thread into a wiki form. So that I would have all "necessary" info in one spot. And hopefully so would other prospective builders.

Baby Huey PP EL84
Bas Horneman's Avatar
diyAudio Moderator Emeritus
Posted in Building
Views 1068 Comments 0 Bas Horneman is offline
Page 2 of 2 1 2

New To Site? Need Help?
Copyright ©1999-2017 diyAudio