CR334626 Reissue Super reverb Amp AB763 question

[drstrange]

Hi *

Here I have a Super Reverb RI frm 09/2010 and its sounding great
with 10" jensens inside. I have only a question relating the output female
jacks of the loudspeakers.

I have here 2 jacks. The one nearest the standbyswitch seems the main
because it has a switch to short the Outputtransformer if nothing is
plugged in. That means the second jack (near to the footswitch jack) is
only usable if in the first jack is already used. ???

First question:
Why do we have a switch on the main jack which shorts the OT if nothing
is connected?? This is not good for the OT in any case?? I wonder about
the reason why.

Second question:
If the first jack with the switch is not used at all, and you plug a load into
the second jack, the OT is shorted but nevertheless to this shorted OT
you here sound in the box. The sound is low and distorted but there
is sound coming out of the external or internal Louspeakers even if the
main jack is empty and the swich of the main jack shorts the OT.
From where is this sound coming?

The question is important because on the backplane there is nothing
written than parallel input (2 Ohms ) etc. If one now plugs during a gig
the intermal loudspeakers in the wrong jack (second) he has then a
shorted OT but hears still little distorted sound and believes his Amp
is defective. This was the case here and i got the Amp but it is ok.
The owner was using the wrong jack during the stressful Gig and
may be he damadged nearly his OT.
Or during a gig he wants to use an external Box only, then he has to
plug out the mains jack and plug i the external box in the mains.
After the gig, the "roady" has to take care to plug in the internal load
back into the right jack (mains jack)

Either I should replace the mains jack with one without swich or
I should write on the backpanel an especially label for the both outputs
(mainsjack vs. secondary jack) because the are not the same and its
dangerous. Or am I to stupid to understand the sense behind the switch???
In my opinion a OT with open secondary without load is safer than an OT
with shortcutted secondary without load from electrotechnical point of view??

Best regards from Stuttgart Germany
Boris Gerlach

[Raybob]

For your first question, it's better for a tube amp to have a shorted OT than an Open secondary. An open can fry the OT.

For your second question, I don't know the Super RI but why not just wire the speaker jacks like an old Super? Should be easy, just wires on the jacks, don't have to mess with the PCB. With an old Super, if you want external cab only, just plug it in the "speaker" jack, not ext spk.

[drstrange]

For your first question, it's better for a tube amp to have a shorted OT than an Open secondary. An open can fry the OT.


You are shure about this??



For your second question, I don't know the Super RI but why not just wire the speaker jacks like an old Super? Should be easy, just wires on the jacks, don't have to mess with the PCB. With an old Super, if you want external cab only, just plug it in the "speaker" jack, not ext spk.

The super rI is wired as well as the old super.

Best regards
Boris