Search found 10574 matches
- Tue Jul 31, 2007 8:24 am
- Forum: Everyones Projects
- Topic: EL509 OTL Amplifier
- Replies: 83
- Views: 78794
Something else as well now I've had a sleep. The way I have the cap connected will bypass the cathode resistors to ground, which will substantially increase the gain of the first stage. The first stage is a 12AX7 high gain valve which makes the relative increase the worst case scenario as there aren...
- Tue Jul 31, 2007 12:11 am
- Forum: Everyones Projects
- Topic: EL509 OTL Amplifier
- Replies: 83
- Views: 78794
Hi Nick Couldn't leave it alone as it was nagging at me. So I had a nice cup of tea, said my relaxation mantra and armed with the circuit diagram and a very strong pair of reading glasses I found this http://homepage.mac.com/scress1958/.Pictures/oops.gif What is this going to do to the feedback? I a...
- Mon Jul 30, 2007 11:23 pm
- Forum: Everyones Projects
- Topic: EL509 OTL Amplifier
- Replies: 83
- Views: 78794
Thanks Nick I might just do that. I know you managed to sort Simon's Blatting 2A3. after he got completely stumped as I seem to be. I don't yet know why and I'm leaving it for tonight but there seems to be -6v of feedback coming along the left channel but only 1.5V coming back down the right. Could ...
- Mon Jul 30, 2007 10:42 pm
- Forum: Everyones Projects
- Topic: EL509 OTL Amplifier
- Replies: 83
- Views: 78794
- Mon Jul 30, 2007 9:03 pm
- Forum: Everyones Projects
- Topic: EL509 OTL Amplifier
- Replies: 83
- Views: 78794
Oh dear, Here we bloody go again! I'm giving up with this neatness lark. It's clip leads and rat's nests from hereon in. So what seems to be the trouble then? Right. The HT to the output stage is isolated by fuses which are removed whilst the checkout is in progress. So far so good. Everything check...
- Mon Jul 30, 2007 10:18 am
- Forum: Speakers
- Topic: Metronome up to date
- Replies: 49
- Views: 33510
Metronome up to date
Hi. There have been anumber of developments with the Metronome speaker Martin King has come up with a proper baffle step correction circuit for the Metronome FE108EZ version. He visited Jim Shearer in New York, who had just completed a pair of the FE108EZ speakers http://www.diyaudio.com/forums/show...
- Sun Jul 29, 2007 11:17 pm
- Forum: Everyones Projects
- Topic: EL509 OTL Amplifier
- Replies: 83
- Views: 78794
That's it! Apart from wiring in the input cables to the selector switch the OTL is completed. It has been powered up and tested without the valves, just to check that the right voltages are appearing in the right places, and with the right polarities. One fault was found with the left channel bias v...
- Sat Jul 28, 2007 11:27 pm
- Forum: Everyones Projects
- Topic: EL509 OTL Amplifier
- Replies: 83
- Views: 78794
The job is nearing completion now. Here are a few pics of the progress made over the past couple of days. http://homepage.mac.com/scress1958/.Pictures/OTLtxs.jpg On go the four transformers. The Sowter at the rear has two HT windings for the driver and output stages. Next size down is the heater tra...
- Wed Jul 25, 2007 8:28 pm
- Forum: Everyones Projects
- Topic: EL509 OTL Amplifier
- Replies: 83
- Views: 78794
Here is the progress so far today. All the hardware has been mounted on the chassis apart from the heater, bias and preamp transformers. These need their looms prewiring and all their the tags double insulating before they are fastened in their final positions and the cover is fitted. A few pics bel...
- Tue Jul 24, 2007 10:25 pm
- Forum: Everyones Projects
- Topic: EL509 OTL Amplifier
- Replies: 83
- Views: 78794
OK The chassis is about done. Here is what it will look like with the valves in. I added some nice little tapered legs, made from some oak I found in the cellar. The result is pure Festival of Britain :D http://homepage.mac.com/scress1958/.Pictures/OTLdone.jpg Here is a close up of a veritable fores...
- Tue Jul 24, 2007 3:00 pm
- Forum: Everyones Projects
- Topic: Colin's gm70 Boat Anchor monoblocs
- Replies: 88
- Views: 72605
- Tue Jul 24, 2007 1:39 pm
- Forum: Everyones Projects
- Topic: EL509 OTL Amplifier
- Replies: 83
- Views: 78794
- Mon Jul 23, 2007 10:55 pm
- Forum: New Users
- Topic: So this is where you have all been hiding!
- Replies: 18
- Views: 17969
- Mon Jul 23, 2007 9:29 pm
- Forum: Everyones Projects
- Topic: EL509 OTL Amplifier
- Replies: 83
- Views: 78794
Before I can get the PSU sorted, the chassis needs doing. This is what I have been concentrating on over the past week. The look of the casework has been heavily influenced by 1950s radiogram consoles. http://homepage.mac.com/scress1958/.Pictures/OTLchassis.jpg The two ivory knobs are from my Mother...
- Sun Jul 15, 2007 9:07 pm
- Forum: Everyones Projects
- Topic: EL509 OTL Amplifier
- Replies: 83
- Views: 78794
Wow! does it work!? It's been checked out on a static test with a multimeter and everything seems to be wired to the right places. I haven't built the power supply yet but as soon as it is done and commissioned then the driver stage will be tested with the HT applied and commissioned before the pow...