What does the +6db input on my amp do to boost the signal? (Schematic attached)

[Dave Locher]

Re: What does the +6db input on my amp do to boost the signal? (Schematic attached)

Really that is lying. If they spesifically say +6db boost. It doesn't do that. It's -6db cut on normal.

It doesn't matter if it practically works just as well. That's false marketing.

I agree, kind of. It's printed right on the amp's front panel, just below the input jack ("HI+6dB") in big font. They could have just labelled them "HI" (or "High") and "LO" (or "Low) without any dB indicated. The manual also lists it as the "HI +6dB input" but in the text just says it is "6 db higher than the low gain input," so they equivocated a bit. If I bought it new I might care, but since I bought it used without a manual I just had to use my ears to figure it out.

It's very similar to the way the high and low inputs on old Marshalls works, same values, but slightly different config.

That makes sense - I believe they were marketed as a solid state ("more reliable") alternative to Marshalls when they came out back in the day. I will say, I have used it for decades with absolutely no maintenance of any kind other than cleaning one volume pot last year so they certainly are reliable!

 

[devastone]

Re: What does the +6db input on my amp do to boost the signal? (Schematic attached)

HI +6dB doesn't say anything about a boost, it just says it is 6dB higher than the other input, not seeing where the problem is.

 

[Dave Locher]

Re: What does the +6db input on my amp do to boost the signal? (Schematic attached)

No problem, just confusing.

 

[Artie]

Re: What does the +6db input on my amp do to boost the signal? (Schematic attached)

Just marketing.

 

[Dave Locher]

Re: What does the +6db input on my amp do to boost the signal? (Schematic attached)

Thank you all for helping me better understand what's going on under the hood. I appreciate it.

 

[Jacew]

Re: What does the +6db input on my amp do to boost the signal? (Schematic attached)

HI +6dB doesn't say anything about a boost, it just says it is 6dB higher than the other input, not seeing where the problem is.

It's stated like it would add +6db to overall signal level. Only if you just compare two inputs to each other it's true.

 

[devastone]

Re: What does the +6db input on my amp do to boost the signal? (Schematic attached)

It's changing the input impedance so the signal is 6dB higher in the high input, it doesn't say anything about boost, its the same as the high an low inputs on old Marshalls and nobody complained about them, it's not false advertising, it's a circuit design thing.

 

[Jacew]

Re: What does the +6db input on my amp do to boost the signal? (Schematic attached)

It's changing the input impedance so the signal is 6dB higher in the high input, it doesn't say anything about boost, its the same as the high an low inputs on old Marshalls and nobody complained about them, it's not false advertising, it's a circuit design thing.

By lowering the input impedance, resulting lower signal level...

 

[Artie]

Re: What does the +6db input on my amp do to boost the signal? (Schematic attached)

It's changing the input impedance . . .

Now you're bringing up a great point. Ideally, you'd always want the input impedance to be the traditional 1meg so that you don't alter the personality of your axe. But that input topology, as do many, presents a 136k input Z on the "Lo" setting. A true boost, (and I realize they don't actually say that), would remain 1meg in either input, while providing unity gain on one, and +6db on the other.

I'm probably meandering into semantics here, but I still thought it was a good point.