Steve
Society Members
vintageradio.co.nz
Posts: 734
|
Post by Steve on Dec 13, 2020 21:11:08 GMT 12
aaaand..... done.
|
|
|
Post by dada on Dec 13, 2020 21:44:37 GMT 12
Who's a clever lad then! Looks great. Cheers, DC
|
|
Steve
Society Members
vintageradio.co.nz
Posts: 734
|
Post by Steve on Nov 29, 2021 20:16:19 GMT 12
I was just using this set as the basis for a video update and realised I never fully explained how I finished this set. It's now sitting under my TV - I really like it... but there was a couple of steps from when you all last were updated until now First, I needed to respray the cabinet - I started by mixing up some lacquer with some dark brown tint in it for several coats on the shoulders, then coated the whole set in several coats of slightly tinted clear I quite like these little Preval sprayers for small jobs - they work well as long as you dilute the lacquer down enough. One spray can is good for one cabinet typically, and they are about $16 each last time I priced them. Then once that had dried I put some new (old) grille cloth in it from my stash... refitted the chassis and we're done. Here is the before and after... I'm really happy with it.
|
|
|
Post by radioholic on Dec 7, 2021 21:44:21 GMT 12
6B8 screen and plate directly connected? Is this normal?
The 6B8 (and 6B7) pentodes sometimes produce far more gain than is needed, so that it becomes difficult to control the volume at low volume settings. One way to decrease the gain is to connect the screen to the plate , thereby turning it into a triode. This also can improve the sound as it is effectively a form of negative feedback. It also can help to reduce hum if the hum originates in the 6B8 itself (which it often does in my experience).
I don't know why designers used a pentode instead of a triode (e.g. 6Q7) which has more than enough gain. I can't see any upside to using a pentode in this setting.
|
|
Steve
Society Members
vintageradio.co.nz
Posts: 734
|
Post by Steve on Dec 8, 2021 15:47:24 GMT 12
Thanks for those insights James - I suspect the valve choices of the smaller cheaper outfits like Radio Warehouse came down to what they could get in the post-war era - whatever the War Assets Realisation Board was selling that week - or possibly they were getting them on a secondary market from companies buying in bulk from the govt...
It's possible that back in the day with stations blasting high power that this was adequate - but in today's lower-powered AM world (and particularly out here in the fringes of civilisation) it was not nearly good enough.
Cheers, Steve
|
|
|
Post by elorens on Dec 8, 2021 17:28:53 GMT 12
I was just using this set as the basis for a video update and realised I never fully explained how I finished this set. It's now sitting under my TV - I really like it... but there was a couple of steps from when you all last were updated until now First, I needed to respray the cabinet - I started by mixing up some lacquer with some dark brown tint in it for several coats on the shoulders, then coated the whole set in several coats of slightly tinted clear <button disabled="" class="c-attachment-insert--linked o-btn--sm">Attachment Deleted</button> I quite like these little Preval sprayers for small jobs - they work well as long as you dilute the lacquer down enough. One spray can is good for one cabinet typically, and they are about $16 each last time I priced them. Then once that had dried I put some new (old) grille cloth in it from my stash... refitted the chassis and we're done. Here is the before and after... <button disabled="" class="c-attachment-insert--linked o-btn--sm">Attachment Deleted</button><button disabled="" class="c-attachment-insert--linked o-btn--sm">Attachment Deleted</button> I'm really happy with it. Great work, Steve, well done!
|
|