tag:blogger.com,1999:blog-8911053673263812666.post6895101390755989700..comments2022-04-15T07:17:58.728-07:00Comments on doityourselfaudio: 27-71A Single Ended Amplifierbopturahttp://www.blogger.com/profile/09086744481440086768noreply@blogger.comBlogger11125tag:blogger.com,1999:blog-8911053673263812666.post-16850425935741477032018-06-29T11:38:47.241-07:002018-06-29T11:38:47.241-07:00Hi, I have a question, how do you fix up the big c...Hi, I have a question, how do you fix up the big capacitors in the chassis?Anonymoushttps://www.blogger.com/profile/10661070987730660418noreply@blogger.comtag:blogger.com,1999:blog-8911053673263812666.post-49425903319390388362014-04-28T10:35:28.716-07:002014-04-28T10:35:28.716-07:00What level I need at input?
As an alternative sol...What level I need at input? <br />As an alternative solution may and step up transformer at input like the Lundahl LL7903 able to make in arranged 1:4 up to 8volts with an standard DAC output?Miguelhttps://www.blogger.com/profile/16480390307674826108noreply@blogger.comtag:blogger.com,1999:blog-8911053673263812666.post-26981259347577752422014-03-18T01:28:48.891-07:002014-03-18T01:28:48.891-07:00rating of the transformers and choke was unfortuna...rating of the transformers and choke was unfortunately unknown, anyway you need 20mA for the 71a and another 5mA for the 27, so around 50mA for both channels. power transformer should have around 380-410v center tapped and a minimum of 30-40mA (will double with ct) and the choke should ba around 10h 50mA. then you need to adjust b+ (1st cap, bleeder res, etc etc) so to go near 220v on the 71a plate.bopturahttps://www.blogger.com/profile/09086744481440086768noreply@blogger.comtag:blogger.com,1999:blog-8911053673263812666.post-56572216903378874262014-03-17T16:57:15.746-07:002014-03-17T16:57:15.746-07:00The main transformer is 205 - 0 - 205v and how man...The main transformer is 205 - 0 - 205v and how many mA? in same way the choke is 10H/__ mA...Anonymoushttps://www.blogger.com/profile/04574409855493616339noreply@blogger.comtag:blogger.com,1999:blog-8911053673263812666.post-42883426408873439492014-03-17T03:57:19.849-07:002014-03-17T03:57:19.849-07:00you can use a vintage pio or a good new film, 2uF ...you can use a vintage pio or a good new film, 2uF was the available value but 1uF should be ok also.bopturahttps://www.blogger.com/profile/09086744481440086768noreply@blogger.comtag:blogger.com,1999:blog-8911053673263812666.post-20326336540555404412014-03-16T15:38:29.616-07:002014-03-16T15:38:29.616-07:00The cap coupled is 2uf... any type or brand in spe...The cap coupled is 2uf... any type or brand in special? film, pio, teflon?Anonymoushttps://www.blogger.com/profile/04574409855493616339noreply@blogger.comtag:blogger.com,1999:blog-8911053673263812666.post-31136944097594350672014-03-07T05:22:24.768-08:002014-03-07T05:22:24.768-08:00Any sugestion from the preamps on this site?Any sugestion from the preamps on this site?Anonymoushttps://www.blogger.com/profile/04574409855493616339noreply@blogger.comtag:blogger.com,1999:blog-8911053673263812666.post-53339359439845041372014-03-03T04:50:14.742-08:002014-03-03T04:50:14.742-08:00Miguel, the amplifier was really very very good so...Miguel, the amplifier was really very very good sounding, unfortunately there was not enough gain when used with the 12A OT line stage, it needs a more conventional preamplifier.bopturahttps://www.blogger.com/profile/09086744481440086768noreply@blogger.comtag:blogger.com,1999:blog-8911053673263812666.post-13492230098359776802014-03-01T03:12:40.952-08:002014-03-01T03:12:40.952-08:00Many thanks, you are so gentle..Many thanks, you are so gentle..Anonymoushttps://www.blogger.com/profile/04574409855493616339noreply@blogger.comtag:blogger.com,1999:blog-8911053673263812666.post-87613248832921899692014-02-24T09:22:22.090-08:002014-02-24T09:22:22.090-08:00hi Miguel, give me a couple of days to find and pu...hi Miguel, give me a couple of days to find and publish the schematic. thanks.bopturahttps://www.blogger.com/profile/09086744481440086768noreply@blogger.comtag:blogger.com,1999:blog-8911053673263812666.post-72802274039561059822014-02-24T08:56:01.388-08:002014-02-24T08:56:01.388-08:00Hi , i'm very interested in this project of th...Hi , i'm very interested in this project of this tube amp<br />how can i contact you?<br />Thanks in advanceAnonymoushttps://www.blogger.com/profile/04574409855493616339noreply@blogger.com