First Happy New Year 2020 to the Eventide family of users! May the tone be with you!
I did a simple SBGL experiment whereby I plugged the guitar in one input and connected (in SBGL) to an output connected directly top the high Z input of myMarkV guitar amp. This was via unbaanced cable TS-TS. I carefully set a microphone and recorded the noise level of a high gain (IIC+) guitar tone. This way, I can see the level in LogicProX by the height of the signal bar (requires vertical zooming).
I then took the SBGL output and fed it directly into a Radial JCR re-amp box via TRS-XLR balanced into the reamp box, then unbalanced TS-TS into the MarkV high Z input.I recorded the noise level, and compared it in LPX. Surprisingly, it is 100% identical, both as measured in LPX as well as by just (subjectively) listening. I re-read the SBGL manual, and it says that all I/O is buffered, and the impedance is 1 megaOhm.
So it appears that the SBGL does act as a re-amp box already, and there is no need for one. Furthermore, I was not using any DI for the guitar and plugged it stright into the SBGL.
UNbless I’m missing somehting, it therefore doesn’t appear that there is any need for DI or re-amp when using the SBGL, UNLESS things start to matter when connecting line level devices like the H9000? This is my next step now that the SBGL is back into my rack.
Curious to know what you guys think?
@joecozzi: Thanbk you so much for the detaied explanation and diagram. As I see it, the RJM device you use which has 4 balanced loops is akin to aSwitvhBlade. However, you clrarly and carefully use DI and re-amp boxes in your setup, so wondering whether it is necessary because the RJM doesn’t have the buffers and high Z that the SBGL has or any other reason?
Happy new year! Cool, love that you did this. Proves I can trust my ears. I set based on tone and perceived noise. You are not missing anything. I’ll give you my thoughts on the SBGL Vs the RJM.
I love SBGL for the heavy lifting with anything that is okay with buffered signal. I use RJM products for switching things that don’t like buffers like analog fuzz and treble boosters. I use an RJM PBC on a board that houses all of those devices and it is controlled by itself or my RJM MMGT. The PBC has three buffers at different spots in the switcher so you can get creative. I added a morning star ML5 for a set of fuzzes I would never stack. Hopefully RJM will make a rack version of his latest PBC6X as it has a matrix switcher, although he may have buffered the whole thing I don’t know.
The other thing I have is a way to completely transformer isolate amp input and the EFX loop connection. Mario (axxess electronics) and I designed some custom boxes that use high end transformers for this. If the Radial boxes are still using Jenson then they should be plenty good too. I read somewhere they stopped for cost reasons a while back, but I don’t know for sure and have not done any testing. I have Radial stuff and it’s always top quality. It has been my experience that whenever I start combining multiple amps and efx loops you end up with ground loops no matter what you do. The ISO boxes solved this for me. They esentially transformer ISO all e connections to the amp and give me polarity switching on a relay I can midi control. I still use the RJM PBY in front of those to select or combine amps inputs from one SBGL out. I have my SBGL maxed so need the extra output. 🙂
Finally, the suposed weakness of the SBGL is the dynamic range for line level devices. We discussed this a bit earlier and RJM does better at this in it’s balanced loops. I don’t have an issue as I am able to gainstage to what I want to hear. However, I am not doing full proper wet/dry type setups. I prefer the interaction of the wet and dry in the same space. If I want a more hi-fi wet it’s usually only in the studio or I do it in a simple wet/dry amp setup and have not had any trouble. I suspect I could also make a full wet/dry with stereo amp and spekers work to my satisfaction as well with the SB, but have not tried it.
