tag:blogger.com,1999:blog-8927460952687081266.post5074394869951535213..comments2024-01-25T09:48:05.944+01:00Comments on a Direct Heating Triode blog: EL84 Push Pull amplifier, the little giantFred Mussethttp://www.blogger.com/profile/15325965306426043700noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-8927460952687081266.post-26132110061425552462021-11-24T14:46:58.454+01:002021-11-24T14:46:58.454+01:00Hi and thanks for your interest. My amp sticks to ...Hi and thanks for your interest. My amp sticks to the original schematic. Just lowered the HV supply and connected the EL84 to UL taps of my transformer. I also changed the feedback resistor to a higher value (82K), but finally went back to the original 68K value. Changed R13_R17 to 1.8K. Hope this helps. FredFred Mussethttps://www.blogger.com/profile/15325965306426043700noreply@blogger.comtag:blogger.com,1999:blog-8927460952687081266.post-79631087929887267602021-11-14T20:03:08.091+01:002021-11-14T20:03:08.091+01:00Hi Fred,
I have an HK300 amp with a similar desig...Hi Fred,<br /><br />I have an HK300 amp with a similar design but with 6V6 output tubes. However, the output transformers are tiny and only has 8 and 16 ohm outputs. Since the impedance of my speakers are 4 ohm, I am not very impressed with the sound. <br /><br />Do you mind sharing the final schematics of your design? Or provide me more specific changes (e.g. new cathode resistor values). I want to build one and listen to it. Ginshinhttps://www.blogger.com/profile/12166755130429083115noreply@blogger.comtag:blogger.com,1999:blog-8927460952687081266.post-9446109450700358572018-01-23T10:36:31.187+01:002018-01-23T10:36:31.187+01:00Hi Juan
think the best would be triode mode.
Conne...Hi Juan<br />think the best would be triode mode.<br />Connect a 100 ohm resistor between anode and g2, connect k and g3. Do not lower DC to stay in the linear region of characteristics. You will probably have to change biasing to draw about 20/22 mA per tube.<br />Make a try and let me know.<br />Fred Fred Mussethttps://www.blogger.com/profile/15325965306426043700noreply@blogger.comtag:blogger.com,1999:blog-8927460952687081266.post-42834059906804000712018-01-19T09:00:48.217+01:002018-01-19T09:00:48.217+01:00Hi Fred. Nice blog. I would like know if it is pos...Hi Fred. Nice blog. I would like know if it is possible downsize this el84 pp design. I have enough with 4 or 5 watts, and extend a little tube life too (I suppose). With down a little the PS will be enough?. Work points change, I suppose, so, what are the best place to change in schematic?<br />Like simplicity, as you. And like 6CG7 too. This schematic is what I searched.<br />Thnak you<br />Juan AntonioAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-8927460952687081266.post-38460129462665499632017-04-26T18:09:55.277+02:002017-04-26T18:09:55.277+02:00Bonjour Fred,
très bel ampli, comme d'habitude...Bonjour Fred,<br />très bel ampli, comme d'habitude. Je découvre aussi les vertus des EL 84, il y a des arguments même en face d'un 300B SE...<br />Cordialement.<br />Brunoraffaele Castelluzzohttps://www.blogger.com/profile/01898711857347501835noreply@blogger.com