Question for Steve D

[cat5]

Or anyone else who has info.

Why didn't you use 1M for the input? I'm sure there was a reason.

I have the C5 head and although I do like the amp very much, it (to my ears) needs a little more articulation.

Would changing the input resistor do this?

If not what could be done, I dont really want to cut it up. I'm looking for more of an early plexi sound, without the insane volume

Thanks for any help, I hope I'm not offending.

I did read the flamers comments in another forum and wouldn't take his advise for any amount of money.

My amp sounds great when played with my Strat but is muddy with my LP.

Dan

-- Thu Feb 09, 2012 6:43 pm --

After doing a ton of reading I wonder if this amp has been modified,(I bought it new at a major music store) it did not come with a box.

Anyway it is a head and when I leave my speaker plugged in and switch to the headphone mode it is still sending signal to the speaker cab. Like the low power mode on the combo.

Is this normal on the head?

Everything I read says the head does not have that feature

-- Thu Feb 09, 2012 8:56 pm --

For Sh.ts and giggles I wired my 4x12 cab for 16 ohms and used the 16 ohm tap. The mud went away even on the neck pup. I had it wired for 8 and I was using the 8 tap.

So problem one solved, I think the 8 ohm tap is run through some kind of a matching network, source of my lost articulation. (or someone modded something in the output section)

What about the speaker staying live with the headphone switch turned to the headphone position? BUT it only happens with the 8 ohm tap, when plugged into the 16 and I flip the switch I get no sound through the cab.

[exotl]

Welcome to the forum cat5!
IMO the source of your problems should have been the wiring of your cab, because according to Ohm's law it is IMPOSSIBLE to wire the same 4x12 for 16Ω and 8Ω as well - to look deeper into the matter you'd have to be more specific about your 4x12 and the impedance of the speakers inside - cheers!

[cat5]

Yes no way to get 4 8 ohm speakers to equal 16, but if you remove 2 from the circuit and wire them in series, you get 2-12's at 16 ohms.

Still would like to know the design reason for the lower impedance input.

[cat5]

Also is the 8 ohm tap supposed to be live with the headphone switch in the headphone position?

[SteveD]

Welcome to the forum cat5.

First off, yes the 8 ohm speaker output stays live even when the headphone mode is selected.

The input impedance was selected as a preference over a range of different guitars/pickups. 470k is found on many older amps and 1 meg is not a rule and never has been. If people want to change it then that is their prerogative.

[cat5]

Good to know the 8 ohm tap is supposed to stay live.

Is the 8 ohm tap routed through a matching network? It does lose articulation.

Another observation, This amp sounds best (to me) through the neck PUP on a strat. Was that your goal?

I wasn't knocking your selection for impedance, just wondered why.

Thanks for answering

[SteveD]

Good to know the 8 ohm tap is supposed to stay live.

Is the 8 ohm tap routed through a matching network? It does lose articulation.
SD: The 8 ohm tap is taken from the relevant secondary on the output transformer

Another observation, This amp sounds best (to me) through the neck PUP on a strat. Was that your goal?
SD: No that wasn't my goal. There will be others who think it sounds best on a variety of pickups and so it goes.

I wasn't knocking your selection for impedance, just wondered why.

Thanks for answering

[cat5]

I returned the amp, and traded it for one that was in a box. The new amp works fine, both taps are articulate. All I can figure is the first one was modified by some idiot. I told the store what I think happened. They did admit it was a previously sold unit.

I'm now a happy customer.

Thanks Steve

[surfnorthwest]

Glad it worked out for you.

[DSL100 Dude]

Someone bought it and brought it back after a jam session. They spilled a beer in it.

[JimDep]

I returned the amp, and traded it for one that was in a box. The new amp works fine, both taps are articulate. All I can figure is the first one was modified by some idiot. I told the store what I think happened. They did admit it was a previously sold unit.

I'm now a happy customer.

Thanks Steve

I'll bet you 10% of my next week's paycheck that it was Guitar Center that you were dealing with. I caught the local GC and several other out of state GC's that were passing defective merchandise to each other that should have been pulled from the inventory lists and either sent back to the manufacturer or sent to repair. Scambags !!