Post by: parasound on Apr 15, 2017 at 10:13 AM
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/8CEA9C72-6D64-4538-914E-B260F8240614_zpsart0chn5.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/8CEA9C72-6D64-4538-914E-B260F8240614_zpsart0chn5.jpg.html)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/19A33DD9-B6D9-4FA8-8F36-1C3B5B7958D3_zpst6ctbgh5.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/19A33DD9-B6D9-4FA8-8F36-1C3B5B7958D3_zpst6ctbgh5.jpg.html)
Trial lay out, in preparation for cutting hole for transformers, tubes & capacitor mount.
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/069FCDA4-4B47-4621-9C7F-DF92D6B7F279_zpszihxuftl.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/069FCDA4-4B47-4621-9C7F-DF92D6B7F279_zpszihxuftl.jpg.html)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/4915C861-0D57-4E52-8778-AAD8CBA43E6A_zpspg87wkb4.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/4915C861-0D57-4E52-8778-AAD8CBA43E6A_zpspg87wkb4.jpg.html)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/6A908570-DD83-46BA-B808-1501C8F9E4D6_zpsyxxnwj99.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/6A908570-DD83-46BA-B808-1501C8F9E4D6_zpsyxxnwj99.jpg.html)
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Post by: parasound on Apr 18, 2017 at 07:31 AM
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/23712586-0F5B-4FA1-804D-386F5B1507C7_zps7dmzf8fk.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/23712586-0F5B-4FA1-804D-386F5B1507C7_zps7dmzf8fk.jpg.html)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/F7EF1DAE-C8FB-45DC-8FF5-BB1C4E987797_zpsexa5f4mx.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/F7EF1DAE-C8FB-45DC-8FF5-BB1C4E987797_zpsexa5f4mx.jpg.html)
Start cutting the aluminum chassis for power transformer mount (using Dremel 3000)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/1CF80365-0F83-4938-9939-95B555D61B72_zpshcekvebf.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/1CF80365-0F83-4938-9939-95B555D61B72_zpshcekvebf.jpg.html)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/DE2ED594-481B-46E2-8745-85C7600EB741_zpseitoq8ih.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/DE2ED594-481B-46E2-8745-85C7600EB741_zpseitoq8ih.jpg.html)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/582E5C65-AFAE-4847-8A4A-7610BC716DBB_zps1nrbvocb.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/582E5C65-AFAE-4847-8A4A-7610BC716DBB_zps1nrbvocb.jpg.html)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/46559028-7076-481F-840D-9330CDE1DD07_zpsayjd5tva.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/46559028-7076-481F-840D-9330CDE1DD07_zpsayjd5tva.jpg.html)
Thanks
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Post by: parasound on Apr 18, 2017 at 08:49 AM
28mm dia & 50mm dia
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/BC65BA03-ADE3-4453-B1DB-B543E99FAB4A_zpsypx5zeod.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/BC65BA03-ADE3-4453-B1DB-B543E99FAB4A_zpsypx5zeod.jpg.html)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/FAD1F91A-F1E0-4823-95DF-E39F6CD6F729_zpszuhdblet.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/FAD1F91A-F1E0-4823-95DF-E39F6CD6F729_zpszuhdblet.jpg.html)
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Post by: parasound on Apr 18, 2017 at 11:38 PM
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/28ADE550-E85C-4375-8F96-831E9A64FB53_zpskcjb16ig.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/28ADE550-E85C-4375-8F96-831E9A64FB53_zpskcjb16ig.jpg.html)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/66CCFFFC-B37E-44FE-96BC-2151B4F1048F_zpszq7zxsud.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/66CCFFFC-B37E-44FE-96BC-2151B4F1048F_zpszq7zxsud.jpg.html)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/590F8A56-8603-4D01-B09B-859E01F2AB55_zpsajraqfyb.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/590F8A56-8603-4D01-B09B-859E01F2AB55_zpsajraqfyb.jpg.html)
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Post by: parasound on Apr 19, 2017 at 04:01 PM
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/74F86345-A1CF-48C1-9B1E-385A4BF2AB1B_zpsegr3udxj.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/74F86345-A1CF-48C1-9B1E-385A4BF2AB1B_zpsegr3udxj.jpg.html)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/513AC06D-ACEA-49B6-BE44-5C13C457103C_zpsuxmcvqhh.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/513AC06D-ACEA-49B6-BE44-5C13C457103C_zpsuxmcvqhh.jpg.html)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/AA87A38A-AC72-46B4-8A5D-33D9D9982772_zps8fotsax9.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/AA87A38A-AC72-46B4-8A5D-33D9D9982772_zps8fotsax9.jpg.html)
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/EAA4FA9B-E77F-416F-8561-1E34D3E16FDC_zpsfpacrwb2.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/EAA4FA9B-E77F-416F-8561-1E34D3E16FDC_zpsfpacrwb2.jpg.html)
Wiring na lang
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Post by: Abad Santos 7 on Apr 19, 2017 at 05:19 PM
Kainggit ung Trapo.... >:D >:D >:D
Post by: parasound on Apr 19, 2017 at 09:38 PM
, pili ka lang Tango U808 or FW20s. Good for your 45
Ayos..... 8) 8) 8)
Kainggit ung Trapo.... >:D >:D >:D
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Post by: redstarrising on Apr 20, 2017 at 10:15 AM
Post by: tony on Apr 20, 2017 at 10:39 AM
Post by: parasound on Apr 20, 2017 at 11:17 AM
Galing mo naman Ronald. Asan na yun sa akin :D :D :D
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Post by: tony on Apr 20, 2017 at 11:19 AM
simplicity makes this a fine way to start with tubes....
as you gain more experience, then you can move on the the bigger tubes...
Post by: parasound on Apr 20, 2017 at 11:22 AM
, then the last time we exchange message was when he still based in SG. another tubero is born, i remember S2KOV, andy is now in canada...
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Post by: tony on Apr 20, 2017 at 12:25 PM
this 2A3 worked best when biased at 250 volts plate and 60mA cathode current, this is the thing to watch out for on power up...
so to complete the operating points, 250volts plate, 60mA current, and -45 volts grid bias....
Post by: parasound on Apr 20, 2017 at 02:03 PM
i use Bourns 100 ohms 2 watts VR (hum pot) - https://www.bourns.com/pdfs/3590.pdfi still get messages from Andy from time to time....
this 2A3 worked best when biased at 250 volts plate and 60mA cathode current, this is the thing to watch out for on power up...
so to complete the operating points, 250volts plate, 60mA current, and -45 volts grid bias....
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Post by: tony on Apr 20, 2017 at 02:46 PM
that is because at a plate voltage of 250 volts, plate resistance is 800 ohms approx. so that three times that or 2400 will give more or less power with reasonable distortion...max power is at twice plate resistance but distortion will be higher...
Post by: parasound on Apr 21, 2017 at 11:30 AM
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/B1C89B79-92C3-4E69-BA49-B93CECFBE8CF_zps15ps9iff.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/B1C89B79-92C3-4E69-BA49-B93CECFBE8CF_zps15ps9iff.jpg.html)
Pero meron Hum
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Post by: parasound on May 01, 2017 at 05:12 PM
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Post by: tony on May 02, 2017 at 07:32 AM
Post by: parasound on May 07, 2017 at 12:12 AM
good job.....congrats...
Post by: tony on May 07, 2017 at 08:59 AM
your amp look clean, but the basic principles of running B+ and ground returns will be the same...
Post by: parasound on May 07, 2017 at 11:07 AM
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/6sl7%20-%202a3_zpsnbmmp3op.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/6sl7%20-%202a3_zpsnbmmp3op.jpg.html)
https://youtu.be/sSTQOZddQik
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Post by: tony on May 07, 2017 at 12:32 PM
Post by: parasound on May 07, 2017 at 01:43 PM
23 weeks ang rotation mo?
Post by: tetablanco on May 09, 2017 at 09:40 PM
Wiring Done
(http://i12.photobucket.com/albums/a201/ronaldcorrales/Mobile%20Uploads/B1C89B79-92C3-4E69-BA49-B93CECFBE8CF_zps15ps9iff.jpg) (http://s12.photobucket.com/user/ronaldcorrales/media/Mobile%20Uploads/B1C89B79-92C3-4E69-BA49-B93CECFBE8CF_zps15ps9iff.jpg.html)
Pero meron Hum
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Master TonyT told me that humming is a common feature of direct heated tubes.
Post by: parasound on May 09, 2017 at 10:34 PM
Edrel S currently building one (same circuit) for him, malaman kung saan nagkamali.
Thanks
Master TonyT told me that humming is a common feature of direct heated tubes.
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Post by: tony on May 10, 2017 at 08:53 AM
Master TonyT told me that humming is a common feature of direct heated tubes.
more so with 300b because of the 5 volts in the heaters, humdingers are definitely required...
there are those who advocate the use of Rod Coleman regulators,
but as Tim de Paravicini would have it, "i do not mix water with wine"
i tend to agree....:D
Post by: tony on May 10, 2017 at 08:56 AM
Malaman natin pag balik ko at na i re layout yung components and tamang grounding..
Edrel S currently building one (same circuit) for him, malaman kung saan nagkamali.
Thanks
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grounding is real...
in all my builds, i use a common psu ground point,
where all wires that need to be at 0 volts are joined there...
another principle is that all B+ psu wires need a return to 0 volts ground, if you do this, then hum are avoided...
Post by: parasound on May 10, 2017 at 09:16 AM
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Post by: Abad Santos 7 on May 18, 2017 at 07:34 PM
Do not connect your safety gnd and your signal gnd directly together.
Your safety gnd should be as short as possible connected directly to your chassis.
Then the center tap of your power transformer connected to the first negative terminal of the filter capacitor.
Do not use this as the start of star gnd since this is the noisest. Tap another wire going to the 2nd filter capacitor. This point can now be considered as the start of star gnd or gnd bus.
From the 1st capacitor terminal, install a gnd loop breaker circuit to connect to chassis for safety.
Your audio circuit already indicated which terminal need to be connected to gnd bus. Just follow it and you will be good.
Cheers.
Post by: tony on May 18, 2017 at 07:56 PM
it is bolted to the chassis at that point...this protects the user from shocks in case there is a power leakage to chassis...
Post by: parasound on May 19, 2017 at 01:06 PM
Nald,
Do not connect your safety gnd and your signal gnd directly together.
Your safety gnd should be as short as possible connected directly to your chassis.
Then the center tap of your power transformer connected to the first negative terminal of the filter capacitor.
Do not use this as the start of star gnd since this is the noisest. Tap another wire going to the 2nd filter capacitor. This point can now be considered as the start of star gnd or gnd bus.
From the 1st capacitor terminal, install a gnd loop breaker circuit to connect to chassis for safety.
Your audio circuit already indicated which terminal need to be connected to gnd bus. Just follow it and you will be good.
Cheers.
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Post by: parasound on May 19, 2017 at 01:07 PM
yes, safety ground connects to one of the bolts holding the IEC power inlets,
it is bolted to the chassis at that point...this protects the user from shocks in case there is a power leakage to chassis...
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Post by: parasound on Jul 19, 2017 at 09:15 PM
(https://uploads.tapatalk-cdn.com/20170719/dd22db1d25b62096ded86f79b92af94f.png)
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Post by: tony on Sep 08, 2017 at 11:43 AM
to really push the 2A3 around, a strong driver with lots more
current than the 6sl7 can provide is desireable...
Post by: parasound on Sep 09, 2017 at 03:26 PM
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Post by: tony on Sep 09, 2017 at 03:38 PM
Post by: parasound on Sep 09, 2017 at 03:53 PM
thanks.
yes...12by7, D3a, 12HL7 etc...even the el84 will do nicely...
Post by: parasound on Dec 28, 2017 at 09:26 PM
Rewiring done by Mr. Felix, Thank you very much po sa wiring and NOS Mullard GZ37
(https://uploads.tapatalk-cdn.com/20180117/d91df4e6a7f851b9380d6a6107ce8c35.jpg)
(https://uploads.tapatalk-cdn.com/20171228/1a5f8489b7d6a2b8dcc5509527c30ad1.jpg)
(https://uploads.tapatalk-cdn.com/20180117/1badb12d0b4a0ae9460a4047b443d91f.jpg)
(https://uploads.tapatalk-cdn.com/20171228/bd45873826ad9796e7670beaac5218ab.jpg)
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