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D3A-300B Amplifier
D3A-300B Amplifier
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Old 13th June 2018, 09:53 PM   #71
santitrucco is offline santitrucco  Argentina
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Old 14th June 2018, 06:08 AM   #72
popilin is offline popilin  Argentina
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Quote:
Originally Posted by rongon View Post
If trying to fulfill popilin's suggestion, you'd need to find a triode with so-so linearity, high mu, and high gm.
That's the idea, a mu follower and a source follower DC coupled to 300B.

6GK5 also works very well in simulations, but was discarded for aesthetic reasons and the difficulties to obtain 7 pin sockets here in my country.
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Old 14th June 2018, 05:16 PM   #73
santitrucco is offline santitrucco  Argentina
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I have a lot of E180F tubes , i put plug & play them , and the amplifier play music wonderful..170v 18ma ..
May be is not so powerful like d3A tube , but is enough..
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Old 18th June 2018, 05:04 PM   #74
santitrucco is offline santitrucco  Argentina
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Default Cathode 300B motor run Capacitors ?

Is good option to use 100uf MKP motor run in cathode 300B tube for replacement electrolytic capacitor ?
I have a lot of room..

Santiago
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Old 19th June 2018, 07:05 PM   #75
kmtang is offline kmtang  Canada
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It is good to try. Different kind of capacitor will have different sound.

It is hard to know what is your cup of tea.

Johnny
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Old 19th June 2018, 07:11 PM   #76
kevinkr is offline kevinkr  United States
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D3A-300B Amplifier
Yes, they can work well.. I like ASC motor runs. In addition to the 100uF cathode bypass motor run you can add a 20uF film cap from the cathode cap (filament end) to the B+, this will provide some canceling of ripple on the power supply.

Don't confuse motor run and motor start caps, you want run caps.. The start caps are usually short lived electrolytics.
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Old 19th June 2018, 07:46 PM   #77
azazello is offline azazello  Bulgaria
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Quote:
Originally Posted by santitrucco View Post
Is good option to use 100uf MKP motor run in cathode 300B tube for replacement electrolytic capacitor ?
I have a lot of room..

Santiago
Cap for cathode 300B must be best quality /it define quality of sound/ like Black Gate, Rubycon, Elna, Nichikon. Every regular cap is not suitable....but You can try...
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Old 20th June 2018, 04:45 AM   #78
soulmerchant is offline soulmerchant  Switzerland
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I am doing ultrapath with DC Link film capacitors. Not so expensive, and better IMHO than electrolytics such as Elna cerafine or Nichicon muse. I prefer them to the crazy expensive black gates too...

To cancel any residual PSU ripple, CR couple power cathode to input/driver cathode (like original loftin-white circuit).

Ian

Last edited by soulmerchant; 20th June 2018 at 04:48 AM.
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Old 20th June 2018, 02:37 PM   #79
juanitox is offline juanitox  France
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for my own DRD or loftin white Set amp i always prefer the usual bypass cap to ground with big film caps than any ultrapath type as it always bring some positive feedbach ( sounds more natural without for my ears).
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Old 20th June 2018, 05:10 PM   #80
santitrucco is offline santitrucco  Argentina
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Is true that electrolytic Mundorf ECap 63V capacitors are so good that films in place bypass cathode ?
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