sessionette Compact sounds disorted and tinny

[Lyrics]

Hello.

My sessionette bass amp sounds distorted and like a tin can. Any ideas. Speaker is fine. Thnx. Cyril

[Geddys nose]

Sounds like a blown Mosfet , I'd get it serviced. Nice amp BTW I had one and the guitar version back in the '80's.

[bertbass]

If I remember correctly, Session used these in their amps, http://www.ilpelectronics.com/amplifiers/audio.asp

[Lyrics]

Do you mean the end stage power mosfet or the preamp op amps?

[Geddys nose]

Mine sounded like yours and it was the output stage.

Cheers

[Bassman Steve]

I have access to Stewart Ward, the man behind Session. I can ask him if you like?

[MoonBassAlpha]

It could be one of the large power resistors in the power amp stage having fractured the solder to the pcb. They sit high off the board and can vibrate. It might be worth going over it with a soldering iron first just in case. This could manifest the same as one of the output fets having blown.
On mine, it just manifested as a crackle when played loudly, but if it had become completely disconnected I think it would have sounded distorted (half the waveform) and lacking in bass.

[Lyrics]

[quote name='Bassman Steve' timestamp='1415887816' post='2604857']
I have access to Stewart Ward, the man behind Session. I can ask him if you like?
[/quote]

That would be excellent. Sometimes it sounds ok but after a few minutes it distorts again. Especially in the low freqs. If i use headphones it's just fine.

Thanks!

[Lyrics]

[quote name='MoonBassAlpha' timestamp='1415915664' post='2605299']
It could be one of the large power resistors in the power amp stage having fractured the solder to the pcb. They sit high off the board and can vibrate. It might be worth going over it with a soldering iron first just in case. This could manifest the same as one of the output fets having blown.
On mine, it just manifested as a crackle when played loudly, but if it had become completely disconnected I think it would have sounded distorted (half the waveform) and lacking in bass.
[/quote]

My problem is similar. Thank you. I will check this.

[Bassman Steve]

Can you just summarise the exact problem for me please? That way I can cut and paste your explanation into a single message to Stewart. Say if it's intermittent and the fact that the headphone jack is fine. I'll pass it to him and see what he says.

[Lyrics]

@Bassman Steve.
I will do some more testing and post the results this weekend. Grtz.

[Lyrics]

@Bassman Steve

I've tested the combo with all settings neutral, no compression. Passive P-bass, Lo input. The sound is tinny and slightly distorted. Distortion becomes worse after a few minutes of playing and stays distorted. If I roll of the highs on the bass the distortion increases. If I plug in my earphones in the phones output the sound is fine. I love it! Same if i use the unbalanced DI. If I use the speaker again, the sound is distorted again and distortion increases with time. I've tested the speaker on my Markbass amp and it sounds fine.

It would be great to get advise from Stewart Ward.

Grtz, Cyril

[Bassman Steve]

Ok Cyril, I'll drop Stewart a line and see what he reckons.

I've had a couple of these myself. Lovely amps but just not really man enough to gig - which Stewart acknowledges.

[Lyrics]

update: the fets on the cooler are from TI and have nummers BD249C and BD244C. I think they are not original (j82 and k226 from what I read). Any thoughts on this?

here's a pic of the output stage: is this original???

Edited November 23, 2014 by Lyrics

[MoonBassAlpha]

It doesn't look anything like the one mine had, I think my f.e.ts were mounted on to the chassis. Is this one of the early ILP power modules? (Caveat: I had mine quite a while ago and my memory is not what it was!)

[Lyrics]

[quote name='MoonBassAlpha' timestamp='1416784880' post='2613633']
It doesn't look anything like the one mine had, I think my f.e.ts were mounted on to the chassis. Is this one of the early ILP power modules? (Caveat: I had mine quite a while ago and my memory is not what it was!)
[/quote]

No, I found out this is a cheap repacement for the original amp.

I'm thinking on putting this in:

http://www.djuke.nl/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=6&category_id=2&vmcchk=1&option=com_virtuemart&Itemid=8