spiralstairs wrote:
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There are minor differences between Hiwatts of different eras, which we have aimed to capture here. The Normal channel of the Triwatt is voiced like a Who amp, with the cathode bypass cap, which gives it a bit more gain. Gilmour's Hiwatts also have that extra gain, due to the cathode cap in the Normal channel. Brent's DR103 is from the era where the normal channel doesn't have the cathode bypass cap, so that there's a bit less gain, together with more clarity. Brent clearly prefered this approach, and also reasoned when he wants more gain, he can engage the extra "OL" boost stage - which is very true. So we went with Brent's request and snipped out the cap.
That's somewhat old information, from a thread while the amp was still in development. We eventually went with Brent's preferred approach as the default, following tests by other experienced players, and the preamp is now identical to an early '70s super-clean Hiwatt preamp (also like Dave Gilmours'). However, we have also published a table on the schematic showing where exactly to add cathode caps for Who or Jimi Page preamp tone options.
spiralstairs wrote:
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The SAP and Jimmy Page models have the same number of preamp stages as a regular Hiwatt DR. Just they have a bypass cap at the cathode of the stage in front of the tone controls, to give that stage some more gain than in the regular version.
Does this mean the Brilliant channel doesn't have this extra gain? And what is the difference between this and the SAP? Or perhaps the plan changed since those posts, and the triwatt is set without these cathode bypass caps?
The Brilliant channel has a low value cathode cap, even in the very clean DR preamps, where the Normal channel doesn't. So we've kept with that. We never set out to really emulate the SAP preamp, since we have the Biacrown style OD stage which IMO does the job better.
spiralstairs wrote:
Basically, I'm looking for Hiwatt *crunch* and then the extra lead stage, not hiwatt clean + lead. I realize setting the OD low can give that crunch. I also realize crunch can be gotten from the stock 4-hole version if hitting it hard with humbuckers + a perhaps a cleanboost. Also I've never had a chance to try a linked Hiwatt, so perhaps that is the missing picture. So ignoring the actual balance control, how does it sound just adding the extra gain from the SAP preamp to what is already there? Where exactly would the extra bypass cap be placed, or how does this look exactly?
Actually a regular DR013 or DR504 will crunch when you turn up the Master Volume, but at that point your ears will suffer severe pain.
The Triwatt gives that kind of power tube crunch without the ear damage - even when you don't use the Overdrive stage. The next thing is that if you want some more crisp preamp crunch like the Who, SAP or Jimmy Page amps, the main thing is to put a 12AX7 in the phase invertor position. Then hit the chords for "Won't Get Fooled Again" and feel yourself grinning ear to ear
A lot of rock players with Hiwatts of that era used to swap a 12AX7 into the PI, including Townshend, Page, Gilmour and Martin Barre, to name just a few. It seems to have been the thing all "real" rock guitarists did back then.
You can also add the cathode caps shown in the tweaker's table on the schematic, but you probably won't need to. The other thing I would like to emphasise is that the Overdrive stage is a Hiwatt design and also gives *the Hiwatt crunch*, but adjustable anywhere between almost clean to a raging roar. It's also important to understand that this isn't just an odd-on in front of the preamp, like a clean boost pedal would be. The OD stage is integral within the preamp, coming between the first and second preamp stages, exactly the same as in the Hiwatt Lead amps. The Triwatt just lets you bypass that preamp stage via a switch or relay.
spiralstairs wrote:
And I get what you're saying Tripower, thanks! The OD style I think is a very nice option and I realize the balance control isn't that useful, but I'm more thinking about having it built-in as always on boost (perhaps on just 1 channel?)
So just leave a 12AX7 in the PI position. Adding cathode caps as shown on the schematic is an option in addition to that. Or you could just short out the OD switch, so that the Overdrive (ak OL) stage is always engaged, as with a Hiwatt Lead amp.
Like Tripower says the SAP preamp isn't that great in the way it works.