ADA Preamps > MB-1
ADA MB-1 Problems... Sound is good on start and suddenly rises to high humming.
SMOO:
Hi all ADA Users!!
I am new to this forum and have questions about my MB-1 its very good condition but has a fault. The sound is good low noise and high level att start up. Then after a while of usage a humming noise starts. I haven thought of it before as something faulty. While recording synthesiser base lines in my studio upstairs i notised the humming on the recording. i disconnected all transformers surrounding it but the noise remained at a pretty high level, while listening to the recording i realised that the noise wasn't appearing in the beginning. so i restarted the MB-1 and the sound disappeared. I don't know what to do? Could it be hardware or maybe the old tubes? I bought it on sale of my local dealer for under 50 € for several years ago and haven't been using it a lot. Not at all after our band lost the rehearsal space we played at. Its unmodified and haven't been tempered vit in any way. Are there any others among you that got the issue?
Restarting it makes it usable for a while in studio its ok but not in the long run playing live base.
Help an newbie ADANIAC!!!
Peter H. Boer:
Hi and welcome,
An easy way to check if it's indeed connected to the tubes (or the tube circuit) is to see if the fault also appears using a full SS patch.
But if the original tubes are in there it may be time for a tube swap anyway :))
I've had a decent 'upgrade' in sound with high gain JJs
Peter
MarshallJMP:
I agree with Peter,install some new tubes.Let us know how that goes.
SMOO:
Is the SS Patch included in the presets? And ill check my local store for some tubes. Any suggestions on tubes for lower noise on high gain. Ill be driving the noise waves on a marshall DBS System in a live situation. And for info i tested the MB-1 again tonight and found that if i keep input on tube side on 5.0 and out on 5.0 the noise levels are bearable in a recording situation and at maximum output level.....It is only appearing on presets with more than 5.0 on in and out settings. Thanks for quick replies. Ill be back when the tubes are changed.
rnolan:
I haven't played with an MB1 but if it's similar to the MP1 then SS is a voice option so run up a new patch and select SS as the voice (although I assume there is a SS factory patch, probably a few).
Tubes are very subjective and you can end up with quite a few "spares" working out what's best for you. I put boogie str tubes in my old MP1 and they were great. I tried some in my MP2 and they were also good but seemed to break up a bit on the low e. Doug's tubes reconed they were JJ but with boogie they could be a variety. I finally settled on the New Sensor Mullard 12 AX7 re-issues and I love them. They would be good in an MB1. You can also use 2 different tubes (as I think Dante does in his MP2) to get the sound you want. The tubes in the ADA pre-amps give you 4 stages of gain (2 in each tube). Some of the guys here have played around with various combinations. My tendency would be to put a lower gain tube before a higher gain tube.
Another thought, are you running much compression in your patches ? And if so what ratio ? High compression ratios and a low threshold (ie all the signal being compressed) would add noise as the noise floor will be elevated compared to the signal. Easy to check though, just turn the compressor off in the patch.
Another thing that can add noise is not having the gain structure optimised. Anyway new tubes wont hurt and may well solve your problem.
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