Peavey Vypyr Tube 120 Headphone Socket Problem

[Kidderman]

I just bought a used Peavey Vypyr Tube 120 combo in great condition. It's clearly been well cared for. No apparent issues with the overall sound and functions. Obviously, it's loud. It's OK at low volume, but I wanted to see how it sounds using the headphone socket. There are two problems: First, when I plug headphones in (I've tried three different pairs),the main speakers don't disconnect and there's no output from the 'phones socket. The second-pretty strange-problem is that the headphones appear to become microphonic. If I tap on them, the tapping can be heard through the speakers. I can even hear my voice when speaking into the earpieces. The amp is coupled up to a Sanpera II floor unit. I'm pretty clueless about how amps work in general, but this issue has me puzzled, to say the least. I'm awaiting delivery of a MIDI to USB cable, which I'm told is how firmware updates are installed on these amps. I'm kinda doubtful if a firmware update (if one is necessary), would solve the issue. Does anyone have experience of a similar issue with the Peavey Vypyr range and if there's a fix? Any advice would be appreciated.

[MarkusBass]

Haven't the headphone socket been replaced with incorrect type by previous owner? Can you asked him?

Mark

[Kidderman]

Haven't the headphone socket been replaced with incorrect type by previous owner? Can you asked him?

Mark

I appreciate your response, Mark, I checked with the seller. He hasn't done anything to the amp since buying it from new. The amp's in pretty much mint condition, so the headphone socket is stock. He also hasn't updated the firmware. I'm hoping that when I get the MIDI to USB converter cable and update the firmware, it'll cure the problem. Any Vypyr owners had a similar problem and solved it with a firmware update? I still don't get the microphonic headphones thing. Weird.
Thanks again.

[Enzo]

The phones jack is right below the USB? So the AUX in is just above the USB? Any chance the two jacks are on a small board that is inverted? In other words, plug the phones into the AUX jack and see if that functions to kill the speakers and is no longer microphonic.

Look at the USB connector, is the angled corner side to the left or to the right?

[Kidderman]

Thanks, Enzo. No luck, unfortunately. Headphones into aux input makes no difference. Angled corner side of USB is to the left as I look at it. Just double checked headphone socket. Doesn't cut sound from speakers, headphones still microphonic.

[Enzo]

I still think they are electrically confused. I could be wrong. The small board with those jacks has a couple ribbon cables. There is an 8 pin one at P4. That cable goes to the main board where I think it is also P4. If that ribbon is turned around or off a pin, we might have this symptom.

[Kidderman]

It makes sense, Enzo. Looks to be straightforward to pull the chassis out. I'll check how those ribbon cables are seated. If they appear to be OK, I'll swap the ends over and see what happens. I'll get back with the outcome. Appreciate your help.

[Jazz P Bass]

First off, does the Aux In jack function?

If so, move on.

The Headphone Out is driven directly by a high current TCA0372 opamp.
If IT failed in a gross manner, it could be passing the headphone (as a microphone) signal into the power amp input.

The headphone jack utilizes a 'pull up' resistor which then goes to the main microcontroller.
Inserting a HP plug alters the voltage that the micro input receives.
The micro is what is actually 'muting' the speaker out.
Tube 120.zip

Added schematic crops:
Vypyr DSP - Pull Up.pdf
Vypyr DSP - P4_ HP Jack.pdf
Vypyr DSP - micro input.pdf

[Kidderman]

First off, does the Aux In jack function?

If so, move on.

The Headphone Out is driven directly by a high current TCA0372 opamp.
If IT failed in a gross manner, it could be passing the headphone (as a microphone) signal into the power amp input.

The headphone jack utilizes a 'pull up' resistor which then goes to the main microcontroller.
Inserting a HP plug alters the voltage that the micro input receives.
The micro is what is actually 'muting' the speaker out.
[ATTACH]43359[/ATTACH]

Added schematic crops:
[ATTACH]43360[/ATTACH]
[ATTACH]43361[/ATTACH]
[ATTACH]43362[/ATTACH]

Thanks for your response. Whilst my understanding of electronics is limited, I understand the principle. I'll be looking at the ribbon cable on the board-as advised by Enzo-to check if there's an issue with that. While I'm there, are there any visual checks which I could make which might establish whether there's a failure elsewhere?

[Enzo]

It neer hurts to look things over - in fact that is first thing I'd do, even while looking for my ribbon connector. I'd look close to make sure there is not an exposed male pin or row of them under one of the connectors.

But I doubt there is anything "burnt up" on here, as this is not the sort of failure that could result from a simple conponent going bad.

[Kidderman]

I'll be looking closely. Here's hoping I get back with a positive result.

[Kidderman]

I've now pulled the chassis and located the small board which services aux, headphones and USB. There is no obvious sign of anything being displaced. The two ribbon cables-one 12-pin and the other 8-pin-appeared to be correctly seated in their sockets. Same at the board where they go to. I swapped the ends of both cables, making sure they were again correctly seated. On powering up again, the problem is still there. That is, plugging in headphones doesn't kill the speakers, there's no sound in the headphones and they are microphonic. I've tried the aux input. It just about works, but only when master volume is on zero. Even then, whatever I play through it sounds very quiet. Turning up the master makes the sound almost disappear completely and sound like it's going through some kind of effect. (Stompbox and Effects controls are on Bypass). USB appears to work. I connected to a PC and the amp is recognised as a recording interface. So, I'm kinda stuck. It would be great to have these things working, but it would be beyond my capabilities to diagnose and make the necessary repair. It looks like swapping the board out is something which I could attempt-if the board was available as a spare- but I may be wrong. I guess it's possible that one of the components which Jazz P Bass referred to in his reply could be the source of the problem. I think I'd be way out of my depth in dealing with micro components. In any case, the fault may lie elsewhere so I could be wasting time, effort and money. If the information in this post rings a bell with anybody, any suggestions would be welcome.

[Kidderman]

I'm just wondering again about the possibility of a firmware update curing this problem. The code which appears on the first three knobs from the left when I hold buttons 1 and 4 on power up indicates that the version currently installed is 1.1.1, which seems pretty far back from 1.59 (people are generally positive about that version). I can't find any Vypyr posts-tube or otherwise-which refer to a similar kind of problem and if it got solved. What I am hearing is that there is a considerable risk attached to updating firmware, particularly on early model Vypyrs. Although I've now got a MIDI to USB converter, I'm reluctant to try an update unless I get a clear indication that it's likely to work with regard to the headphone output problem.

[nickb]

With the P4 plug correctly inserted, there is no way the headphone can act as a microphone. OTOH, thinking along Enzo's suggestion, if the cable were inserted the wrong way round so that pin 1 of the cable went to pin 8 of the connector than you would get the symptoms you describe. I would not expect anything from the AUX in at all but if you are driving it hard enough all bets are off.

Can you take a couple of clear pictures of each end of the cable so we can see how it is inserted?

[Kidderman]

With the P4 plug correctly inserted, there is no way the headphone can act as a microphone. OTOH, thinking along Enzo's suggestion, if the cable were inserted the wrong way round so that pin 1 of the cable went to pin 8 of the connector than you would get the symptoms you describe. I would not expect anything from the AUX in at all but if you are driving it hard enough all bets are off.

Can you take a couple of clear pictures of each end of the cable so we can see how it is inserted?

I took some photos while I was checking the cables. As soon as I figure out how to upload them, I will.