E
ed
- Jan 1, 1970
- 0
Hi,
Has someone who has constructed the power amp as shown on
http://sound.westhost.com/project03A.htm be kind enough to answer
these questions.
1.what are the resistances shown at the supply fuses with fuses
removed and multimeter leads reversed?
2.Any expert-0.33 Ohms fusible resistors or 1.0 Ohm wirewound
resistors(min. available here)-which is preferable for this amp?
I want to know if my amp(hardwired-1 channel only) has a soft short
as Mr.Elliot discusses on Troubleshooting and Repair guide on his
website(i didn't fully understand that paragraph).Resistance bet.
supply- about 150 Ohms and infinity with leads reversed(slightly
inaccurate analogue multimeter).output and ground-infinity and about
17k. Series lamp 100W glows lightly (about 10 watts-sudden on and off)
and the 20 Ohms safety resistors resistors get hot on no load (they r
supposed to stay cool acc. to Mr.Elliot).Output voltage is almost 0v,
supply voltages about 25v and voltage drop across safety resistors
about 13v (which should be max 1v acc. to Mr.Elliot).
Output transistors and 1 fuse(3A) have blown once with series lamp
and safety resistors removed.That time, I had got a very
loud(distorted?) sound(3sec) when speaker(35w,8 Ohm-intend to listen
at low volume) was connected and safety resistors and lamp were in
place even when the music source(sony cd discman D148 CR-line output)
was at low volume 1.
100pF caps are ceramic(as min. polyester which is available is
1000pF).
No variac.Power supply is taken from the Tandberg TR 2025 MB amp(which
is awaiting repair due to unavailbility of output transistors).
(thanks to Mr.Elliot for putting up so much info.(invaluable to
beginners) on his website)
Thanks
Ed
Has someone who has constructed the power amp as shown on
http://sound.westhost.com/project03A.htm be kind enough to answer
these questions.
1.what are the resistances shown at the supply fuses with fuses
removed and multimeter leads reversed?
2.Any expert-0.33 Ohms fusible resistors or 1.0 Ohm wirewound
resistors(min. available here)-which is preferable for this amp?
I want to know if my amp(hardwired-1 channel only) has a soft short
as Mr.Elliot discusses on Troubleshooting and Repair guide on his
website(i didn't fully understand that paragraph).Resistance bet.
supply- about 150 Ohms and infinity with leads reversed(slightly
inaccurate analogue multimeter).output and ground-infinity and about
17k. Series lamp 100W glows lightly (about 10 watts-sudden on and off)
and the 20 Ohms safety resistors resistors get hot on no load (they r
supposed to stay cool acc. to Mr.Elliot).Output voltage is almost 0v,
supply voltages about 25v and voltage drop across safety resistors
about 13v (which should be max 1v acc. to Mr.Elliot).
Output transistors and 1 fuse(3A) have blown once with series lamp
and safety resistors removed.That time, I had got a very
loud(distorted?) sound(3sec) when speaker(35w,8 Ohm-intend to listen
at low volume) was connected and safety resistors and lamp were in
place even when the music source(sony cd discman D148 CR-line output)
was at low volume 1.
100pF caps are ceramic(as min. polyester which is available is
1000pF).
No variac.Power supply is taken from the Tandberg TR 2025 MB amp(which
is awaiting repair due to unavailbility of output transistors).
(thanks to Mr.Elliot for putting up so much info.(invaluable to
beginners) on his website)
Thanks
Ed
