Search found 586 matches
- Wed Jan 31, 2018 12:38 pm
- Forum: Dumble Discussion
- Topic: Why not switch OD & PAB at once?
- Replies: 16
- Views: 2117
Re: Why not switch OD & PAB at once?
That's great to see posts summarizing Dumble amp features - for us, newcomers - as a side note 8) My question departs much from the original but my readings make me think (maybe I'm wrong) that the PAB is (somewhat) useless without the OD engaged (& vice-versa) - hence my question. If I ever build ...
- Fri Jan 12, 2018 2:41 pm
- Forum: Technical Discussion
- Topic: OD tone stack alternatives?
- Replies: 12
- Views: 1771
Re: OD tone stack alternatives?
Just replace the 25k mid pot in the original tone stack with something larger, e.g. 100k audio. Up to about 10 o'clock similar to stock, from there on you will get a substantial midboost (really less mid cut).
Cheers Stephan
Cheers Stephan
- Thu Jan 11, 2018 12:28 pm
- Forum: Marshall Discussion
- Topic: Friedman Dirty Shirley thoughts.
- Replies: 62
- Views: 30089
Re: Friedman Dirty Shirley thoughts.
I also have converted one of my amps to that circuit. I have 5k6 as default cathode resistor on the second stage and add another 5k6 plus a .47uf cap for a gain boost. I also upped the cathode bypass cap on the first gain stage to get fuller clean tones at low gain settings. And my mid control is a ...
- Thu Jan 11, 2018 12:21 pm
- Forum: Dumble Discussion
- Topic: Why Dumble cleans?
- Replies: 26
- Views: 5526
Re: Why Dumble cleans?
I am probably in the minority but having tested a few different D-style circuits I clearly prefer AB763 circuits for clean tones.
- Mon Dec 18, 2017 3:48 pm
- Forum: Technical Discussion
- Topic: Mesa Boogie Mark III - How to get more touch response?
- Replies: 15
- Views: 7849
Re: Mesa Boogie Mark III - How to get more touch response?
Meanwhile I cracked the Mark III open to compare to the schematic on schematicheaven. My amp is a Purple Stripe 60 Watt model with reverb but w/o the graphic EQ. There are some differences to the lead circuit: - the resistor between the lead drive pot wiper and ground is 330k, not 150k as in the sch...
- Tue Dec 05, 2017 4:09 pm
- Forum: Technical Discussion
- Topic: Holland Amp
- Replies: 38
- Views: 6016
Re: Holland Amp
This amp looks a lot like the Holland Brentwood I once had - reverb unit into Plexi circuit. That was a nice sounding amp.
I found the sweep control rather useless and converted it to a PPIMV.
Cheers Stephan
I found the sweep control rather useless and converted it to a PPIMV.
Cheers Stephan
- Tue Dec 05, 2017 4:02 pm
- Forum: Technical Discussion
- Topic: Mesa Boogie Mark III - How to get more touch response?
- Replies: 15
- Views: 7849
Re: Mesa Boogie Mark III - How to get more touch response?
I know this is an old thread but I finally got around to progress. I did not yet attack the Mark III but I implemented the Mark lead circuit in another amp and then started to mod it until I got what I liked. What I came up with was the following seemingly minor changes to the basic circuit (BTW if ...
- Thu Nov 06, 2014 8:58 am
- Forum: Vox/Hiwatt Discussion
- Topic: Vox/Matchless Cut control
- Replies: 21
- Views: 9976
Re: Vox/Matchless Cut control
I have had good results with either 250k or 500k audio pots.
Cheers Stephan
Cheers Stephan
- Thu Nov 06, 2014 8:56 am
- Forum: Technical Discussion
- Topic: Monkeymatic Penta (Matchless Clubman inspired)
- Replies: 115
- Views: 24363
Re: Clubman build
@SilverFox: I'm not sold on this design. My original goal was to experiment with EF86 pentode in the preamp (but not in V1) to learn what color it could give to the circuit. Instead, as I found with this amp, it does not distort at all, but pushes the PI into clipping very easily. It's a good sound...
- Fri Oct 31, 2014 5:16 pm
- Forum: Marshall Discussion
- Topic: Budda SD30 to Naylor SD60 preamp?
- Replies: 14
- Views: 5204
Re: Budda SD30 to Naylor SD60 preamp?
The Minimalist HRM is great. I have it in my rebuilt JMP 1959 SLP. Does everything from slight crunch to high gain with a twist of the gain knob.
Cheers Stephan
Cheers Stephan
- Wed Oct 29, 2014 1:15 pm
- Forum: Trainwreck Discussion
- Topic: Z-Wreck compatible DIY hobby build
- Replies: 13
- Views: 2813
Re: Z-Wreck compatible DIY hobby build
Beautiful amp!
Cheers Stephan
Cheers Stephan
- Wed Oct 22, 2014 11:27 am
- Forum: Technical Discussion
- Topic: Monkeymatic Penta (Matchless Clubman inspired)
- Replies: 115
- Views: 24363
Re: Clubman build
But the PI values in that amp are lifted straight from a Vox AC30. to put it in relative terms, a power amp plate supply of 300V with an 8v bias voltage. That's a third (or a fourth) of what you're contending with in this output stage. Exactly. That's why I suggested to lower the PI tail resistor. ...
- Fri Oct 17, 2014 2:56 pm
- Forum: Technical Discussion
- Topic: Monkeymatic Penta (Matchless Clubman inspired)
- Replies: 115
- Views: 24363
Re: Clubman build
All good points. Those 270R cathode resistors on the power tubes are definitely too small. I use 390R on each power tube in my Chieftain build with 410V on the plates and 27V on the cathodes. That puts them close to but under 100% plate dissipation. If you want to increase the headroom of the PI, lo...
- Fri Jun 13, 2014 12:01 pm
- Forum: Technical Discussion
- Topic: Monza master volume mod
- Replies: 9
- Views: 1932
Re: Monza master volume mod
My favorite PPIMV is the LarMar. To me it has 3 advantages over the cross line master as used by Matchless, Bad Cat et al - it works better at lower volumes - makes the entire amp sound better - does not affect the cut control (or in the Monza the tone control which is really a cut control with a la...
- Fri Jun 13, 2014 11:59 am
- Forum: Technical Discussion
- Topic: Monza master volume mod
- Replies: 9
- Views: 1932
Re: Monza master volume mod
I don't have a schematic for that amp but there is one out for the Mazerati GT. Same amp minus 2 output tubes plus the third control (which is a variable load on the grid load resistor before the PI.ampfab wrote:do you have a schematic?
I'm not having any luck.
Cheers Stephan