Series Instrument with F-2B, SF-2, and IN-2

[edwin]

So, I know this was discussed before but I can't find the thread.


I'm thinking about resurrecting my rig to include the above devices and what would seem to make the most sense would be to plug the bass into the IN-2, have the outputs go straight to the F-2B, then from those outputs to the SF-2 rear inputs, and then the outputs of that into the return jacks of the IN-2. I remember trying this before but ended up with some weird gain structure that created noise, as in popping with loud notes.


Has anyone figured out the best way to do all this without any issues?


TIA

[jazzyvee]

Here are some links to my threads documenting my quest to do the same.
.
https://club.alembic.com/index.php?topic=25841.msg273803#msg273803

https://club.alembic.com/index.php?topic=25841.msg273803#msg273803



Currently i am using two F1-x preamps with one channel of the SF-2 in each preamp send/return loop
and that works fine. But i could reduce my rack weight and simplify the setup if could get the F2-B working with out the audio anomalies.
Even when using the F-2B together with SF-2 without the in-2 still gives me audio issues which i don't understand as both these units have been around for decades.

Please let me know how you get on.👍🏾🎶🤨

[matbard]

I always hope in an improved IN-2 Mk.2...

[edwin]

Here are some links to my threads documenting my quest to do the same.
.
https://club.alembic.com/index.php?topic=25841.msg273803#msg273803

https://club.alembic.com/index.php?topic=25841.msg273803#msg273803



Currently i am using two F1-x preamps with one channel of the SF-2 in each preamp send/return loop
and that works fine. But i could reduce my rack weight and simplify the setup if could get the F2-B working with out the audio anomalies.
Even when using the F-2B together with SF-2 without the in-2 still gives me audio issues which i don't understand as both these units have been around for decades.

Please let me know how you get on.👍🏾🎶🤨

Thanks! It's very helpful to know that you didn't get it quite worked out. I'm wondering if maybe attenuators on the outputs of the F-2B going into the SF-2 might help.

Edwin

[JimmyJ]

I have no direct experience trying to use all these pieces together but I'm doing my best to understand by reading the manuals.  I tried in Jazzyvee's thread too but we never quite got there...  I'm still trying!   

I noticed one thing in the F1-X manual: there is an internal jumper which allows you to change the front panel input to 0db gain.  The standard setting adds 10db right off the bat and you shouldn't need that if you are already using the F-2B as your pre.

I have to admit that I don't understand the "direct gain" and "filter gain" controls and how they change between stereo and mono modes...  But there must be a way to do what you guys want to do without the signal clipping somewhere in the chain.

Jimmy J

[rv_bass]

So, I know this was discussed before but I can't find the thread.


I'm thinking about resurrecting my rig to include the above devices and what would seem to make the most sense would be to plug the bass into the IN-2, have the outputs go straight to the F-2B, then from those outputs to the SF-2 rear inputs, and then the outputs of that into the return jacks of the IN-2. I remember trying this before but ended up with some weird gain structure that created noise, as in popping with loud notes.


Has anyone figured out the best way to do all this without any issues?


TIA

Maybe the loop of IN-2 first and last is somehow creating noise.  Maybe try:

Bass->
F-2B ->
S-F2 ->
IN-2 ->
Power Amp, board, etc.

This way the signal path is linear without a loop.

[jazzyvee]

 Not sure i understand that RV_Bass but if you are using the In-2 with a series bass the In2 that is the start of the chain isn't it so not sure how you could move it to the end of the chain.?
As others mentioned in my old thread you can feed the output from your preamps back into the rear of the In-2 then take the signals out of the other jacks on the back of the In-2, to your power amp and get your post signal at the two DI-outs on the front of the unit.
Or you can take your preamp outs to your power amp and the DI outs on the In-2 just have the signal straight off the bass pre-the preamp.

I tried both options and tried changing the position of the F-2B and SF-2 in the signal chain with and without the loop back to the In-2 and still had issues. Even taking the In-2 out of the signal path and using the F-2B and SF-2. I had my power amp serviced and still had problems.
Even using a non series bass plugging directly into the F-2B & SF-2 combination or reversed still gives the same issue. Though strangely if you max the volumes on the power amp and keep the F-2B gain reallty low it is better but if you have the power amp on a lower setting and get the volume by upping the F-2B input gain and bass volume then then you have problems.

Hope we can find a consistent solution. Even though the F-2B was brand new NOS from an alembic dealer in Paris i may have to get it looked at just to rule any issues out. I'm convinced the SF-2's are ok since I have used them successfully with my F-1X.
Phew...Keep those thoughts coming in I have some free time at the end of next week to have another go at re-wiring the rack.

[rv_bass]

Jazzyvee, thanks for the feedback.  I don’t have an IN-2, so I’m not that familiar with their operation, your summary of connections helped.

I have an SF-2 and a couple of F-2B preamps, so I’ll try a few SF-2/F-2B combinations this week and see if I encounter the same noise issues you experiences.

Rob

[gtrguy]

I record with these. I will hook them up to my DAW and look at the level visually to see how to get the least noise. Also, some tubes can be more noisy than others and I have hooked them up to my computer with the F-2b or F-1X case off and swapped tubes in and out to find the most quiet but good sounding ones.

[edwin]

I record with these. I will hook them up to my DAW and look at the level visually to see how to get the least noise. Also, some tubes can be more noisy than others and I have hooked them up to my computer with the F-2b or F-1X case off and swapped tubes in and out to find the most quiet but good sounding ones.

I don't think it's a tube problem or other maintenance issue. It strikes me as a gain structure or maybe an impedance problem (impedance specs are not published for the SF-2). In general, it seems to work better with the SF-2 before the F-2B, but that creates cabling hassles, having to go from the front of the IN-2 to the back of the SF-2 and then back around to the front of the F-2B and then out of the back of the F-2B into the returns in the back of the IN-2. I suppose if you could tap the F-2B right after the first tube stage with an insert point, it might work better. Or even right at the input.