Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on March 12, 2015, 04:58:54 pm

Title: Is correct this input arrangement ?
Post by: kagliostro on March 12, 2015, 04:58:54 pm

(http://www.diyitalia.eu/forum/download/file.php?id=10814&mode=view)

The connection of the 1M resistor at the input is odd to me  :w2:

The 1M resistor is permanently connected to the signal path and ground and never disconnected by the tip in on the input jack

is this a typo or really the schematic is correct ?

to me the 1M resistor must be connected to ground and to the signal path via the tip on the input jack and this connection confuses me (http://www.diyitalia.eu/forum/images/smilies/Trilly-18-39.gif)(http://www.diyitalia.eu/forum/images/smilies/Trilly-18-39.gif)

 :help:

K

Title: Re: Is correct this input arrangement ?
Post by: DummyLoad on March 12, 2015, 05:17:48 pm

it will work.


the balance control changes the plate loading and thus varies the gain of the second triode when in cascade mode.


the 1M grid leak at the input is just like fender/marshall etc. 


--pete

Title: Re: Is correct this input arrangement ?
Post by: sluckey on March 12, 2015, 05:47:04 pm

That's exactly the same way I do all my single input amps. The 1M is never disconnected by the jack switch in any amp I've looked at. Do you have an example of what you are talking about?

Title: Re: Is correct this input arrangement ?
Post by: kagliostro on March 13, 2015, 01:53:15 am

Thanks Pete & Steve

Quote

it will work.

Quote

same way I do all my single input amps.

What didn't works correctly is my brain, I focused my memory on one of the jack intake of the double input amps

and refused to remember the other

 :embarrassed:

I hope it was late here yesterday when I asked  :sad2: :sad2:

Many Thanks

Franco


p.s.: BTW it will be interesting to join this schematic with the latest work by Steve

Title: Re: Is correct this input arrangement ?
Post by: sluckey on March 13, 2015, 07:07:12 am

Quote from: mresistor on March 13, 2015, 06:58:06 am

kagliostro - do you have a copy where all the words are readable?

What's not readable? I can see that from 20 feet away. Did you forget to click on the pic to see the full size?

Title: Re: Is correct this input arrangement ?
Post by: mresistor on March 13, 2015, 07:09:12 am

didn't realize it was clickable   sorry    meanwhile I found it .pdf on the web    thanks