Quick question on the Hall and Collins Unit

[GAJ52]

This is more a question for Charlie

I was listening to Steve's great video on comparing the sound of the H&CU with echo off and on. I never really understood Wow and flutter, but apart from the fantastic echo's, what else has been added to the main Shadows sound patches i.e. any EQ or reverb etc.

Glen

[John Collins]

Hi Glen,
I know you said your question is for Charlie, but I'd like to help Charlie out answering some of the inquiries, where I can.
Steve has said he used no Reverb or EQ in his clip. The Hall & Collins also has no reverb of any kind in any patch. Various combinations of the delay parameters can give a perception of reverb, just as in some of original echo machines, but again, there is no reverb added. As for EQ, the DRY sound of the unit has Charlie's tube emulation circuitry, (analogue hardware) which does alter the frequency response from input to output, to closely match the response of the Meazzi. Some of the tape emulation circuitry also will produce frequency dependent compression/distortion. Regarding the echo generation, which is performed in the digital domain, there is a lot of frequency shaping done - depending on the machine being emulated. We went to great lengths here to reproduce every nuance of the individual tape heads, and their interaction as well as Record/Replay amps etc. It's basically what took us so long! So you can see that it is quite complex - in summary, the H & C is designed to replace one of those old echo units, in the signal chain. No gain boost, EQ, Reverb or amp simulation. Hope this helps.

[GAJ52]

Many thanks John, there's obviously some very clever 'magic' added to this unit, the results are superb to my ears.

Glen

[localhero]

I discussed this with Charlie on the telephone after I received mine on Wednesday. I immediately heard it and for me the quest is over, thie Hall & Collins is one of the 'magic bullets', the other being able to play correctly.

[rogerbayliss]

Amanda who repairs Meazzi's told me recently that Charlie had gone to great lengths to match FET's to the EC83 valves and their responses and harmonics in the analogue preamp side. I am sure Charlie will tell us more and the tape drive simulates real tape saturation and compression and probably the odd harmonic treatment that gives when driven. Charlie and John have produced a brilliant echo unit no doubts the wait was worth it.

[Charlie Hall]

Hi Roger,
FETs normally produce second harmonic distortion at any signal level (when a source capacitor is used or when the source is earthed without a resistor or capacitor) due to their square law characteristic. Valves have more of a mix of even and odd harmonics (more even than odd) at the lower end of the spectrum, less so at the higher end, and the harmonics tend to increase with increasing signal levels. The output resistance tends to change with signal levels too. This is what I have managed to emulate. It takes some doing to get FETs to behave like this!
The tape drive circuit is done with a gradual frequency selective symetrical soft clipping which produces odd harmonics. One thing I insisted on was no matter how loud the signal is, the clipping circuit will never drive the digital level to maximum headroom, so digital clipping can never occur. This is basically why we don't need an input level indicator, you just use your ears to get the sound you want!
Regards,
Charlie

[rogerbayliss]

Thanks for explaining that Charlie .... brilliant job done !

I notice that slight alterations of the knobs change the sound of a patch and interact to some degree. Also it would seem that the setting you do on one patch translates to the next patches selected no for example echo drive increased will increase all patches as they are selected. I am sure that this is as intended but maybe you could confirm as that is how it seems to me. I originally thought that if you choose a patch that the knobs would not matter till you turned them but clearly they do ?

[Charlie Hall]

Hi Roger,
As you thought, the knobs are not reset when you change the patch selection. Whatever any knob is set at is what you always get, which I think is easier to work with as you can always see exactly what is happening. The first 3 knobs, Dry Level, Echo Drive, and Echo Level, are simply controls in the analogue preamp, very similar to how they would be in a Meazzi. The Feedback and Wow & Flutter knobs control the digital effects, but even so, they work in a similar way to the first 3 knobs.
Regards,
Charlie

[rogerbayliss]

Thanks for explaining Charlie

[frankmarvin]

Personally I haven't felt the need to alter anything on the H&C, minor tweaking of my amp and * Bingo * the long awaited sound is there:

Excuse the short message, but my fingers are killing me, I can't stop playing my guitar

Regards, Frank.

[Charlie Hall]

Hi Frank,
Thanks for reporting your findings. I was hoping that the nominal 3 o' clock settings would suit most player's styles.
Regards,
Charlie