I was hoping to get design suggestions for driver stages for my pet project, a big 200W tube bass head. It's more a thought exercise at this point, as I'm sure the price of a 200W OPT with good bass response will shock me back into reality.
As to what's already out there with 200W driver stages, there's of course Dogzilla:
with its DC coupled followers, which is basically what an Ampeg SVT uses:
There's the Weber AB200:
Link removed by moderation
which uses an interstage transformer, which is a little unique for MI.
Thoughts? Of course using SS followers is always an option but I wonder if that might not be a goode solution for MI.
As to what's already out there with 200W driver stages, there's of course Dogzilla:

with its DC coupled followers, which is basically what an Ampeg SVT uses:

There's the Weber AB200:

which uses an interstage transformer, which is a little unique for MI.
Thoughts? Of course using SS followers is always an option but I wonder if that might not be a goode solution for MI.
Last edited:
Nobody cares? Just thought of another candidate, how about a DC coupled pentode LTP like in the Tim Mellow OTL? I don't think I've come across that yet topology in commercial MI amps, but I bet that is because using small tubes as drivers is much more cost effective.
The MI guys have all moved to the instrument & amps thread which is where this thread belongs. I'll move it there..
Thoughts? Of course using SS followers is always an option but I wonder if that might not be a goode solution for MI.
My thoughts.....Mosfets are your friend. I use them in HiFi and MI. The bigger the amp the more they help.
<snip>
There's the Weber AB200:
Link removed by moderation
which uses an interstage transformer, which is a little unique for MI.
Thoughts? Of course using SS followers is always an option but I wonder if that might not be a goode solution for MI.
Please repost link to schematic, but please note in the post that it is a link to the schematic.
An externally hosted image should be here but it was not working when we last tested it.
This is a link to that schematic.
I like ampeg and would start there. What's the deal with Weber going the mile with a transformer coupled EL34 as driver (which would be able to truely drive the output tube) but wasting the potential with series capacitors and 15kohm gridstoppers? Might as well use a wimpy 12ax7 then!
I like ampeg and would start there. What's the deal with Weber going the mile with a transformer coupled EL34 as driver (which would be able to truely drive the output tube) but wasting the potential with series capacitors and 15kohm gridstoppers? Might as well use a wimpy 12ax7 then!
The more I look at the Weber design the less I like it. I think you're right about the grid stoppers: they are that size to primarily limit grid current when overdriven and not just to prevent RF oscillation. I looked at pictures and the interstage transformer is just a wimpy little thing. I think it's probably a mediocre design wherein reusing as many existing catalog parts as possible was a primary design objective.
Hi
DC connection with tube or FET driver will kick *** on any cap connection! the bedst cap is the one that have just been replaced by a DC connection.
*
best regards
Karsten
DC connection with tube or FET driver will kick *** on any cap connection! the bedst cap is the one that have just been replaced by a DC connection.
*
best regards
Karsten
Hi
DC connection with tube or FET driver will kick *** on any cap connection! the bedst cap is the one that have just been replaced by a DC connection.
*
best regards
Karsten
...so your suggestion is?
- Status
- Not open for further replies.
- Home
- Live Sound
- Instruments and Amps
- Suggestions on driver stages for big tube MI amps.