Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tubenit on August 18, 2011, 11:56:37 am
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Since I like to experiment and tweak ......... I got rid of the CF behind V2a on the SongBird and converted that into another gain stage. I like the transformation ALOT! This is a very very fun amp and now is more in the D-style tone of the Tweed Overdrive Special and Tweed BluezMeister.
Like anything, there are some plus and minus factors in changing an amp. I've never been able to get all the tonal features to be a "10", but I am learning to accent some features that I like and what it takes to do that.
I can get incredible sustain and very nice harmonics and blooming out of this tiny SE amp now. The overdrive is exceptionally clear, smooth and transparent and not muddy at all with lead or chording. Also the passive effects loop seems to work even better with this added gain stage. The delay has a warmer fuller sound to me.
The editable schematic and layout are in the SCH Library.
I've attached a before (Carolina SongBird) and after (Carolina SongBird PLUS) comparison. I will try to record something within the next 2 weeks to demonstrate the tone of this amp and how well it sustains, etc....
http://www.el34world.com/Forum/index.php?topic=11889.0 (http://www.el34world.com/Forum/index.php?topic=11889.0)
EDIT I had been having some minor frustration with the mid pot making the mids too gritty sounding beyond maybe "3". I decided to remove the 2.2uf cap off the V1-8 cathode and reduce that resistor from 2.2k to 1.5k. I feel like this added considerable smoothness to the amp with no negative downside. I can easily crank the mid pot to 7-8 with the mids staying smooth sounding now.
With respect, Tubenit
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Wow... I'm having difficulty keeping up. Seems since i'm on the road I spend more time laying things out than actual building. I was trying to layout a Carolina songbird, variant with all tube with an extra gain stage and the clean channel. Maybe my best bet would is to build 2 and have one with the stock configuration and a second for trying to fit in the clean channel. With 2 amps I can compare the standard version and the one with the clean channel.