question on ultra linear hook-up

[dwp]

I have a Dynaco 50 W OT with UL taps, if I use them, do I connect the UL taps directly to pin 4, without the 1K plate resistors? Aren't I losing a filter stage as well by doing this instead of using the board resistors? (Normal Hoffman Plexi style power rail)
Thanks in advance, dwp

[RicharD]

The UL taps do go to the respective screens.  You can go with or w/o the 1k screen resistors, although 1k may be a bit large.  You no longer use the screen node in the power supply.  You will probably want to up the dropping resistor value between the unused DC node and the next one to lower the voltage down stream.  I just did a UL amplifier and I used 100 ohm screen resistors.  Look at the Janitor thread for this schematic.  Don't let the choke placement throw you.  I used a big honkin' 10 Henry 300mA choke in front of the plates.

[dwp]

thanks for the reply, I found the janitor thread after I posted. Very helpful. Thanks again......

[jojokeo]

I just did a UL amplifier

Buttery, how does the UL hook-up affect an amp's sound and character vs. w/out it hooked up this way?

[RicharD]

Dunno.  I only tried the UL wiring.

[Ritchie200]

Jojo,
UL=lots more headroom.  Fender had that twin UL and everyone seems to hate it because it is too clean and sterile.  The Major is also UL and is not a typical plug-and-play Marshall.  If you just plug in, you will be VERY disappointed.  However, when you do get it dialed in, there is no other amp that sounds like it.  The only way to describe it is to listen to Deep Purple's Made in Japan.  It has a distinct character.  A lot of amps sound good when you play a chord and then thin when you play a lead, or great lead and too muddy on chords.  The Major has a searing kind-of distortion that sounds great for lead and rhythm - very balanced without knob diddling or stomp boxes.  Obviously there is more to an amps character than just one thing - KT88's, cathodyne PI, etc., etc...  Ritchie's amp tech, who worked for Macintosh prior, swears "the" tone comes from the UL design.  I have a couple of OTs with UL taps that I am going to play with one of these days....

MVeryHO Jim

[jojokeo]

Thank you "my man, my man on the pur-ple mountain"! I love that riff.  I was thinking it to be a little like NFB in making it cleaner but also different. You confirmed and explained it very nicely. Thank you!

I'm already thinking of diddling w/ it for el84s to get a cleaner output section maybe in combo w/ my DumbleWatt preamp section or = ? If I'm not mistaken Mr Fischer w/ some of his Trainwreck amps used UL didn't he?

[Willabe]

There's a number of guys using UL OT's and not using NFB becauce the UL taps generate a small amount of FB on there own. IIRC, DR. Z is among those doing this.


             Brad       

[jojokeo]

Ritchie's amp tech, who worked for Macintosh prior, swears "the" tone comes from the UL design.  I have a couple of OTs with UL taps that I am going to play with one of these days....

When will you have the time btwn runnin', rulin', racin', reefin', and riffin'??? 

Thank you "my man, my man on the pur-ple mountain"! I love that riff. 

sorry, bad play on words there 

[Ritchie200]

When will you have the time btwn runnin', rulin', racin', reefin', and riffin'??? 

Thank you "my man, my man on the pur-ple mountain"! I love that riff. 

sorry, bad play on words there 

Who are you describing?!?!?!  That sounds like you pal!

Now, as far as your "Silver Mountain" play on words....dont give up your day job!!!
Jim

[jojokeo]

 
I meant it as a purple coralline algae mountain in a reef-sense tied w/ Richie/Rainbow and it didn't come out right. Day job good, humor bad