welborne Labs drd 300b

RE: welborne Labs drd 300b , posted on March 16, 2015 at 23:34:47
horny Audiophile Posts: 745 Location: holland Joined: October 17, 2003	Thanks i find this already but i have a different input tube the 6n1p

RE: welborne Labs drd 300b , posted on March 17, 2015 at 06:21:57
awsjr Audiophile Posts: 235 Location: Austin, Tejas Joined: November 30, 2006

RE: welborne Labs drd 300b , posted on March 17, 2015 at 09:47:42
horny Audiophile Posts: 745 Location: holland Joined: October 17, 2003	Yes thats the amp i think but there are no values in the schematic

RE: welborne Labs drd 300b , posted on March 17, 2015 at 11:14:40
Chip647 Audiophile Posts: 2647 Location: The South Joined: December 24, 2012	Just measure the parts in your amp.

RE: welborne Labs drd 300b , posted on March 17, 2015 at 14:27:24
horny Audiophile Posts: 745 Location: holland Joined: October 17, 2003	I buy these amps and i think it is not original anymore they used very good components like Shinko resistors and black gate caps but i don't now if the values are as the original amp used to be so i will check it with a schematic

RE: welborne Labs drd 300b , posted on March 17, 2015 at 14:50:05
Chip647 Audiophile Posts: 2647 Location: The South Joined: December 24, 2012	R4 and R5 are the only two absolutely critical values. You can tell if the existing values are correct if the 300B is passing around 90 mA. If someone messed with the values, they would have to know what they were doing or the amp would not work.

RE: welborne Labs drd 300b , posted on March 18, 2015 at 11:42:51
awsjr Audiophile Posts: 235 Location: Austin, Tejas Joined: November 30, 2006

RE: welborne Labs drd 300b , posted on March 18, 2015 at 16:40:26
horny Audiophile Posts: 745 Location: holland Joined: October 17, 2003	thank you very much awsjr! i will check it the little tube in this amp is not the 6n1p but they put a 6BQ7a in it is this a better sounding tube? i have no 6n1p to try it

RE: welborne Labs drd 300b , posted on March 18, 2015 at 18:29:52

Paul Joppa
Industry Professional

Posts: 7295
Location: Seattle, WA
Joined: April 23, 2001

The 6N1P is a great sounding tube - at first. A number of people have found it to fade within a year of typical use, though. Just reporting what I've heard, I don't have enough personal experience with it to comment on my own.

The 5670 is fairly close, with IIRC the same pinout. On the spec sheet it's quite linear; I like it myself, and it's available in premium forms (GE five star, for instance).

RE: welborne Labs drd 300b , posted on March 19, 2015 at 23:38:55
horny Audiophile Posts: 745 Location: holland Joined: October 17, 2003	i will order a pair 6n1p and put them in the amps. then they are original again they put Tantalum resistors in and the big (parafeed?) cap is an Obligato the values are good i think

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welborne Labs drd 300b

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