Search found 123 matches
- Thu Dec 21, 2017 3:16 pm
- Forum: Valves
- Topic: Feedback with Battery Bias
- Replies: 24
- Views: 19695
Re: Feedback with Battery Bias
That's a very good point! I'll check those Black Gates too.......
- Mon Dec 18, 2017 4:08 pm
- Forum: Valves
- Topic: Feedback with Battery Bias
- Replies: 24
- Views: 19695
Re: Feedback with Battery Bias
Hi Nick,
The resistors were Arcol metal-cased wirewound attached to the chassis and rated at 50 watts. So the 100 watts current seems consistent with failure and the failed transformer.
David
The resistors were Arcol metal-cased wirewound attached to the chassis and rated at 50 watts. So the 100 watts current seems consistent with failure and the failed transformer.
David
- Mon Dec 18, 2017 1:53 pm
- Forum: Valves
- Topic: Feedback with Battery Bias
- Replies: 24
- Views: 19695
Re: Feedback with Battery Bias
Hi Mike, Unfortunately there is no evidence of a 300 fault. There was no change in the music output before the bang, eg the usual crackle or pop you get with 300b failure, nor any sign of redplating or other sign of failure. All four valves still work perfectly. It seems to point more to an output t...
- Sun Dec 17, 2017 11:50 am
- Forum: Valves
- Topic: Feedback with Battery Bias
- Replies: 24
- Views: 19695
Re: Feedback with Battery Bias
So, I checked everything out and the casualties are the two large Arcol wire wound resistors and one half of the output transformer on one channel which has gone open circuit. I'm pretty sure the blow up occurred when the feedback was connected the correct way round as the amp was working with no fe...
- Sun Dec 10, 2017 6:33 pm
- Forum: Valves
- Topic: Feedback with Battery Bias
- Replies: 24
- Views: 19695
Re: Feedback with Battery Bias
Hi All, There was nothing strange that a photo would have revealed about the way battery bias had been installed. It was in the standard way as was the resistor put in in place of the battery bias as described. The amp is a clone but uses exactly the same circuit as the kit. The only mod done was to...
- Fri Dec 08, 2017 5:17 pm
- Forum: Valves
- Topic: Feedback with Battery Bias
- Replies: 24
- Views: 19695
Re: Feedback with Battery Bias
Hi All, The amp has worked perfectly for 5 years. Over that time I’ve tried cathode bypass capacitor, no bypass capacitor and then landed on battery bias with no issues and glorious sound. The only issue now and all connections are correct is the feedback squeal which occurs when using battery bias ...
- Mon Dec 04, 2017 7:57 pm
- Forum: Valves
- Topic: Feedback with Battery Bias
- Replies: 24
- Views: 19695
Re: Feedback with Battery Bias
1-300Bcircuit.pdf Hi Nick, here's the circuit. The amp wrks perfectly with or without cathode bypass cap, some preferring the sound without and also with battery bias. I used the original circuit values and all I get is feedback with the switch in the feedback on position, the amp behaving perfectl...
- Sun Dec 03, 2017 6:56 pm
- Forum: Valves
- Topic: Feedback with Battery Bias
- Replies: 24
- Views: 19695
Re: Feedback with Battery Bias
Hmm, I get screaming feedback connected like this.............
- Thu Nov 23, 2017 7:55 am
- Forum: Valves
- Topic: Feedback with Battery Bias
- Replies: 24
- Views: 19695
Re: Feedback with Battery Bias
Thanks Nick
- Wed Nov 22, 2017 9:06 pm
- Forum: Valves
- Topic: Feedback with Battery Bias
- Replies: 24
- Views: 19695
Feedback with Battery Bias
Hi All,
on the WAD300b pp the cathode resistor is 1k and feedback is applied at the cathode end of a 33r lift resistor. If I'm using battery bias does anyone know if I can connect the battery minus to the 33r lift resistor and apply feedback in the same way?
Thanks
on the WAD300b pp the cathode resistor is 1k and feedback is applied at the cathode end of a 33r lift resistor. If I'm using battery bias does anyone know if I can connect the battery minus to the 33r lift resistor and apply feedback in the same way?
Thanks
- Sun Jan 31, 2016 1:27 pm
- Forum: Everyones Projects
- Topic: Calling All WAD 300b Stereo Owners
- Replies: 3
- Views: 4272
Re: Calling All WAD 300b Stereo Owners
Ok, the information given me that a transformer set supplied for a WAD 300b stereo clone was that from a WAD 5881 amp was unfortunately incorrect. I contacted Geoff from SP Wound the supplier and he stated that WAD changed the supplier at some stage, and obviously the spec, but Geoff had supplied to...
- Thu Jan 28, 2016 10:50 am
- Forum: Buying and Selling
- Topic: Rare Amplifon 6C33 40 watts per channel amp
- Replies: 2
- Views: 4216
Re: Rare Amplifon 6C33 40 watts per channel amp
Now Phillip for one whose changes in amps nearly equals one's changes of underwear that's a strange question :D There's more than one gourmet meal out there and my house was stacked full of some fine food in the shape of 845 DSEs and a WAD 300b stereo. The poor old Amplify was being under-utilised. ...
- Thu Jan 28, 2016 10:45 am
- Forum: Everyones Projects
- Topic: Calling All WAD 300b Stereo Owners
- Replies: 3
- Views: 4272
Calling All WAD 300b Stereo Owners
Hi Guys, I have started a new London-based business servicing, upgrading and doing new builds of mainly valve amps, although I am also doing Dacs, CD players and the odd solid state amp too. But that’s not why I am writing. I have serviced several WAD 300b clones, some of which I have sourced, and n...
- Sun Dec 13, 2015 12:43 pm
- Forum: Buying and Selling
- Topic: Rare Amplifon 6C33 40 watts per channel amp
- Replies: 2
- Views: 4216
Rare Amplifon 6C33 40 watts per channel amp
For sale very rare Polish made Valve Amplifier Amplifon Audio WT-40 in full working order and great condition .RRP was around 3000 euro .This amp uses a quartet of 4 x 6C33 triodes on the output stage. The amp was serviced in April 2014 but did not meet my high standards of service so the following ...
- Wed Jun 11, 2014 1:18 pm
- Forum: Assorted Stuff
- Topic: Adding sub out rca sockets to valve amp
- Replies: 9
- Views: 5913