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BBE 383 Distortion
- Thread starter ancjr
- Start date
.
Thought there was a chance we overlooked a "shorty" 1/4 cable which could be commandeered for the project.
Riis
For a little background...
I've used the BBE 383 for a long time to bypass the preamp via the return input on my Behringer amp head. I had forgotten why I was using it this way. Tonight I removed the BBE and plugged the bass direct into the Behringer. The Behringer preamp doesn't have enough gain, is very noisy, the EQ seems like it's working against me, and all the switchable "features" are gimmicky and annoying. I had the input gain on the Behringer maxed and the master turned to 12 o'clock, whereas with the 383 preamp the master on the Behringer only needed to be turned to 8 o'clock for the same output level. The simple case is that the Behringer has an OK power amp section with a junky preamp in front of it, and why I was using the BBE 383 as a workaround in the first place.
I borrowed a cable and confirmed that bypassing the effects loop of the BBE 383 does clean up the distortion issue. So, whatever it takes to repair the effects loop would fix the distortion... and it also has horribly scratchy pots that need working in every day so I don't pop a driver when changing a setting...
Looking forward, I have another amp I'm working on swapping into the rig and haven't decided if the 383 is going to stay or go when I make the upgrade. I have ideas I'm considering which would take me in other directions...
I've used the BBE 383 for a long time to bypass the preamp via the return input on my Behringer amp head. I had forgotten why I was using it this way. Tonight I removed the BBE and plugged the bass direct into the Behringer. The Behringer preamp doesn't have enough gain, is very noisy, the EQ seems like it's working against me, and all the switchable "features" are gimmicky and annoying. I had the input gain on the Behringer maxed and the master turned to 12 o'clock, whereas with the 383 preamp the master on the Behringer only needed to be turned to 8 o'clock for the same output level. The simple case is that the Behringer has an OK power amp section with a junky preamp in front of it, and why I was using the BBE 383 as a workaround in the first place.
I borrowed a cable and confirmed that bypassing the effects loop of the BBE 383 does clean up the distortion issue. So, whatever it takes to repair the effects loop would fix the distortion... and it also has horribly scratchy pots that need working in every day so I don't pop a driver when changing a setting...
Looking forward, I have another amp I'm working on swapping into the rig and haven't decided if the 383 is going to stay or go when I make the upgrade. I have ideas I'm considering which would take me in other directions...
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The pots on my 383 are really scratchy as well. Probably a common issue with these units.
The scratchy pots and problem with the effects loops may just be corrosion due to the age of the unit. I think the jacks are sealed so you can't really get inside and clean them. But sometime if you work a plug in and out of the jack a couple of times, it will clean of the contact enough to fix the problem.
Here's the Effects Loop.
Notice that both jacks are switching, but the switching function is only actually used with the Return jack (J2). So my guess is your problem is with J2.
Some pots have little vents that allow them to be serviced. Caig Deoxit D5 is recommended quite a bit. Just a quick blast through the port in the pot casing, and then work the control back and fourth. You don't want to soak the unit in D5 as it can cause collateral damage if you get it all over the circuit boards.
- Feb 12, 2006
- 61,086
- 5
- 221,200
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
- Feb 12, 2006
- 61,086
- 5
- 221,200
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
Cleaning the jack that way will not and can not clean the internal normalling switch.
Cycling the return jacks a few times with a 1/4" plug is likely to solve the problem unless the switch contacts are really bad. Is they are that bad, proper replacement is needed.
Cycling the return jacks a few times with a 1/4" plug is likely to solve the problem unless the switch contacts are really bad. Is they are that bad, proper replacement is needed.
As others have noted it is highly unlikely
There is any electrical circuit failure and very unlikely to have bad capacitors.
As noted with with the effect loop bypass
This is a typical problem. Likewise can be common with input jacks . If switching Jacks are utilized for high / low inputs or Passive/Active inputs.
Since in general you've noticed the control pots are scratchy as well. All your symptoms are pretty common normal oxidation issues. Or the switching contacts can have oxidation or the contacts can loose tention and no longer make good contact.
The jack contacts for the tip and ring signal
Can be easily cleaned with typical insertion, reinserted method.
Unfortunately the switching contacts are internal in the jack and insertion/ reinserted methods won't clean the contacts.
If lucky it may be possible to clean the contacts if a small amount of deoxit can be sprayed into to jack housing. It's more likely sealed and hard to reach.
Usually it requires a jack replacement
Or the jack cover if removable, removed for cleaning. Usually there is 4 plastic pins holding on the cover and not removable since the pins are melted into place.
Scratchy pots can be cleaned with a small squirt and working the pot if the pot case isn't completely sealed. Usually there is access near the pins and not easily visible since the pins side is on the bottom and hard to reach since it's pointing towards the board.
A otherwise none recommendation method is to squirt down the pot shaft from the front.
Unfortunately this can force dirt if any into the pot and it will usually remove the needed lubricant on the shaft.
You can replace the lubricant. But only a tiny tiny amount is needed. Usually it's a poor recommendation. Because people over lube the shaft and it leaks into the pot body and can contaminate the resistive elements
There is any electrical circuit failure and very unlikely to have bad capacitors.
As noted with with the effect loop bypass
This is a typical problem. Likewise can be common with input jacks . If switching Jacks are utilized for high / low inputs or Passive/Active inputs.
Since in general you've noticed the control pots are scratchy as well. All your symptoms are pretty common normal oxidation issues. Or the switching contacts can have oxidation or the contacts can loose tention and no longer make good contact.
The jack contacts for the tip and ring signal
Can be easily cleaned with typical insertion, reinserted method.
Unfortunately the switching contacts are internal in the jack and insertion/ reinserted methods won't clean the contacts.
If lucky it may be possible to clean the contacts if a small amount of deoxit can be sprayed into to jack housing. It's more likely sealed and hard to reach.
Usually it requires a jack replacement
Or the jack cover if removable, removed for cleaning. Usually there is 4 plastic pins holding on the cover and not removable since the pins are melted into place.
Scratchy pots can be cleaned with a small squirt and working the pot if the pot case isn't completely sealed. Usually there is access near the pins and not easily visible since the pins side is on the bottom and hard to reach since it's pointing towards the board.
A otherwise none recommendation method is to squirt down the pot shaft from the front.
Unfortunately this can force dirt if any into the pot and it will usually remove the needed lubricant on the shaft.
You can replace the lubricant. But only a tiny tiny amount is needed. Usually it's a poor recommendation. Because people over lube the shaft and it leaks into the pot body and can contaminate the resistive elements
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That may just be a gainstaging and headroom issue. I haven't really used mine for many years but from what I remember, it had pretty limited headroom and it did not clip gracefully. Turn down the Gain and turn up the Volume, so you don't run out of internal headroom.
To get an idea how hard you are hitting the front end, turn on the compressor and set the Threshold at 12:00. If you are really smashing the compressor then you may want to turn the Gain down.
I thought the compressor on this unit was the absolute worst sounding compressor I have ever heard. I used it, but adjusted it so it barely engaged on the strongest dynamics. The control was sort of fiddly so finding the desired Threshold was a bit tricky.
Followed by the equally mandatory "dont over DeOxit the pots" comment.....
Nit sure how I missed the obvious "Agedhorse as Doctor House" comparison, but this really made it obvious. "It's not lupus damn it!"
I always liked my 383. I still have it in a 4-space in my attic. I should let it visit for a while. Never had any issues. But nothing lasts forever except the Atlanta Falcons curse.
