Two Valver. - UK Vintage Radio Repair and Restoration Discussion Forum

mogginski · 3rd Sep 2009, 4:52 pm

Have just this minute finished building a 2 valve set (that was derived from a 1 valve set).

Here are some pictures.

OErjan_S · 4th Sep 2009, 9:52 pm

nice work

mogginski · 4th Sep 2009, 10:23 pm

Many thanks to Station X for editing my previous garbled posting. Will pay more attention next time.

kalee20 · 4th Sep 2009, 11:32 pm

It's a good type of circuit, straightforward, tolerant of component values, which you can have a lot of fun with.

Regarding component values, I'd question the "0.1" capacitor from the DL96 grid (upstream of the 0.01 coupling capacitor) to 0V. This does seem a bit high - do you notice a big lack of treble? I'd go for 0.001µF or so. It's only to stop stray RF getting onto the grid. Try reducing this. With the 4700pF across the headphones to kill any RF which does get through, you might get away without it altogether - although to have a capacitor in each position, is good practice!

3rd Sep 2009, 4:52 pm	#1
mogginski Retired Dormant Member Join Date: Jul 2009 Location: Exeter Posts: 2	Two Valver. Have just this minute finished building a 2 valve set (that was derived from a 1 valve set). Here are some pictures. Attached Thumbnails Last edited by Station X; 4th Sep 2009 at 8:43 pm. Reason: Linked images converted to thumbnails.

4th Sep 2009, 9:52 pm	#2
OErjan_S Retired Dormant Member Join Date: Mar 2007 Location: Skelleftea, Sweden Posts: 250	Re: Two Valver. nice work

4th Sep 2009, 10:23 pm	#3
mogginski Retired Dormant Member Join Date: Jul 2009 Location: Exeter Posts: 2	Re: Two Valver. Many thanks to Station X for editing my previous garbled posting. Will pay more attention next time.

4th Sep 2009, 11:32 pm	#4
kalee20 Dekatron Join Date: Feb 2007 Location: Lynton, N. Devon, UK. Posts: 7,088	Re: Two Valver. It's a good type of circuit, straightforward, tolerant of component values, which you can have a lot of fun with. Regarding component values, I'd question the "0.1" capacitor from the DL96 grid (upstream of the 0.01 coupling capacitor) to 0V. This does seem a bit high - do you notice a big lack of treble? I'd go for 0.001µF or so. It's only to stop stray RF getting onto the grid. Try reducing this. With the 4700pF across the headphones to kill any RF which does get through, you might get away without it altogether - although to have a capacitor in each position, is good practice!