Page 7 of 8

Re: Regurgitator kit Build Thread

Posted: Mon Mar 09, 2020 11:11 am
by Joe Malone
earthsled wrote:
I am working on a html sheetsheet using a formula Rob sent me so this can be more easily calculated by anyone.
Hi Joe - just wondering if this html sheet ever was finished/posted? I'm interested in calculating fixed resistances in place of the trim pot for various levels of gain on the Regurgitator. Perhaps you could share the formula? Thanks for your help!
I did get a fair way with this but haven't completed it. I will dig it out and try to get done finally.

Re: Regurgitator kit Build Thread

Posted: Mon Mar 09, 2020 5:25 pm
by MrMesh
Hi there and thanks Joe/Rob for making this kit! I'm wondering if anyone can help answer a few questions that I have:
1. What is the recommended method of mounting the PCBs to an enclosure? I don't see any mounting holes and was wondering how most people were securing the PCBs - aside from the chassis mount screws of the XLR connectors - if at all.
2. In my efforts to find the right 5k 25-turn trim pot I've come across two separate trim pots that seem to be almost identical, yet the component cost differential is notably large: i. https://www.mouser.de/ProductDetail/652-3296W-1-502RLF and ii. https://www.mouser.de/ProductDetail/81-PV36W502C01B00 . Can anyone identify which of these I'd need for the build?
3. Is the rating of 21mA per card mentioned earlier in this thread accurate? I'm looking to install 10 units into an enclosure and wondering 250mA would cover my power needs.

Cheers!

Re: Regurgitator kit Build Thread

Posted: Mon Mar 09, 2020 8:10 pm
by Joe Malone
MrMesh wrote:Hi there and thanks Joe/Rob for making this kit! I'm wondering if anyone can help answer a few questions that I have:
1. What is the recommended method of mounting the PCBs to an enclosure? I don't see any mounting holes and was wondering how most people were securing the PCBs - aside from the chassis mount screws of the XLR connectors - if at all.
You can mount single pcb in heatshrink tube if cable in and out. Pair or more you can cut a V into the V groove :-) at each end of the pcb so a standoff and M3 bolt can be used. Or if using plastic clip on stand offs drill out unused corner +/-V power pads to 3mm to clip the stand off on to.
2. In my efforts to find the right 5k 25-turn trim pot I've come across two separate trim pots that seem to be almost identical, yet the component cost differential is notably large: i. https://www.mouser.de/ProductDetail/652-3296W-1-502RLF and ii. https://www.mouser.de/ProductDetail/81-PV36W502C01B00 . Can anyone identify which of these I'd need for the build?
Both seem to fit and are the 5k value needed so both should work fine.
3. Is the rating of 21mA per card mentioned earlier in this thread accurate? I'm looking to install 10 units into an enclosure and wondering 250mA would cover my power needs.
8pack regurg with 8 x NE5532A idle current @ +/-18v is roughly 80mA. So if you are only driving 10k loads then 150mA to 200mA is heaps.

Re: Regurgitator kit Build Thread

Posted: Mon Mar 09, 2020 10:13 pm
by Joe Malone
Resistor values for 1dB gain steps from robs regurgitator calculator.

Gain - RGain = R11 + RV1
+18db - 50R
+17dB - 56R
+16dB - 63R
+15dB - 71R
+14dB - 81R
+13dB - 91R
+12dB - 103R
+11dB - 116R
+10dB - 131R
+9dB - 149R
+8dB - 169R
+7dB - 192R
+6dB - 219R
+5dB - 250R
+4dB - 286R
+3dB - 329R
+2dB - 378R
+1dB - 437R
0dB - 507R
-1dB - 593R
-2dB - 696R
-3dB - 1198R
-4dB - 1478R
-5dB - 1198R
-6dB - 1478R
-7dB - 1870R
-8dB - 2440R
-9dB - 3360R
-10dB - 5080R
-11dB - 9280R
-12dB - 35000R

Re: Regurgitator kit Build Thread

Posted: Mon Mar 16, 2020 8:52 am
by MrMesh
Joe Malone wrote:8pack regurg with 8 x NE5532A idle current @ +/-18v is roughly 80mA. So if you are only driving 10k loads then 150mA to 200mA is heaps.
Thanks Joe!

I'll be driving the following loads:
IN: 1 x 6.6kΩ-47kΩ (selectable)
IN: 1 x 40kΩ
IN: 1 x 1MΩ
IN: 1 x 47kΩ
OUT: 2 x "more than 5kΩ"
OUT: 2 x 600Ω
OUT: 1 x 250kΩ (0.5-1.0V) or 500kΩ (10-50mV)
OUT: 1 x 100kΩ

Would the 150-200mA still suffice?
Cheers

Re: Regurgitator kit Build Thread

Posted: Mon Mar 16, 2020 10:51 am
by Joe Malone
MrMesh wrote:
Joe Malone wrote:8pack regurg with 8 x NE5532A idle current @ +/-18v is roughly 80mA. So if you are only driving 10k loads then 150mA to 200mA is heaps.
Thanks Joe!

I'll be driving the following loads:
IN: 1 x 6.6kΩ-47kΩ (selectable)
IN: 1 x 40kΩ
IN: 1 x 1MΩ
IN: 1 x 47kΩ
OUT: 2 x "more than 5kΩ"
OUT: 2 x 600Ω
OUT: 1 x 250kΩ (0.5-1.0V) or 500kΩ (10-50mV)
OUT: 1 x 100kΩ

Would the 150-200mA still suffice?
Cheers
If you are supplying +/-18v and no zeners then yes that will be fine.

Remember the input impedance of regurgitator is 15k balanced and 7k5 unbalanced so driving from a much higher output impedance device will drop lots of level.

Re: Regurgitator kit Build Thread

Posted: Wed Mar 18, 2020 8:34 am
by MrMesh
Joe Malone wrote:Remember the input impedance of regurgitator is 15k balanced and 7k5 unbalanced so driving from a much higher output impedance device will drop lots of level.
Ok, and there'll still be significant loss of signal despite the +18dB gain? Also, is there any way to counter this level drop with this kit by changing any parts around, or is there a more suitable kit for dealing with the higher impedance outputs?

Re: Regurgitator kit Build Thread

Posted: Wed Mar 18, 2020 10:13 am
by Joe Malone
MrMesh wrote:
Joe Malone wrote:Remember the input impedance of regurgitator is 15k balanced and 7k5 unbalanced so driving from a much higher output impedance device will drop lots of level.
Ok, and there'll still be significant loss of signal despite the +18dB gain? Also, is there any way to counter this level drop with this kit by changing any parts around, or is there a more suitable kit for dealing with the higher impedance outputs?
Best to let me know exactly what you are driving into the regurgitator so I can see the problem clearly. Like impedance out and max unbalanced output level and max balanced level you want out?

For high input impedance like 100k input to balanced output. dingo pup kit or tardigrade kits. Input impedance of these kits can be higher like 1Meg but depends on the opamp type used.

Re: Regurgitator kit Build Thread

Posted: Wed Mar 18, 2020 6:37 pm
by MrMesh
Joe Malone wrote:
MrMesh wrote:Best to let me know exactly what you are driving into the regurgitator so I can see the problem clearly. Like impedance out and max unbalanced output level and max balanced level you want out?
Hey Joe, thanks again for your time. I'll either be patching from/to the balanced outs/ins of my Antelope Orion 32 interface or from/to the balanced Aux Sends/Echo Returns of my Trident 65 console into one of 4 effects units. The 4 units in question all feature unbalanced connectivity, and are:

i. Roland SRE-555 - Chorus Space Echo: 1 x input, 6.6-47kΩ (switchable in 3 stages). 2 x outputs, 'more than 5kΩ'
ii. A/DA STD-1 - Stereo Tapped Delay: 1 x input, either 40kΩ or 1MΩ FET input (switchable). 2 x 'single-ended, 1/4 phone jacks, drives 600 ohm'.
iii. Dynacord S65 - Tube Tape Delay: 1 x input, 17 mV / 1MΩ. 1 x output, choice of either '0.5-1.0V / 250kΩ' or '10-50mV / 500kΩ'
iv. Telefunken Echomixer - 3-ch mixer w/Spring Reverb: 1 x input, choice of either '≤ 3mv / 2.5kΩ', '80mV / 47kΩ' or '500mV / 270kΩ'. 1 x output, 100mV / 100kΩ.

Re: Regurgitator kit Build Thread

Posted: Sat Mar 21, 2020 9:46 am
by Joe Malone
MrMesh wrote:
Joe Malone wrote:
MrMesh wrote:Best to let me know exactly what you are driving into the regurgitator so I can see the problem clearly. Like impedance out and max unbalanced output level and max balanced level you want out?
Hey Joe, thanks again for your time. I'll either be patching from/to the balanced outs/ins of my Antelope Orion 32 interface or from/to the balanced Aux Sends/Echo Returns of my Trident 65 console into one of 4 effects units. The 4 units in question all feature unbalanced connectivity, and are:

i. Roland SRE-555 - Chorus Space Echo: 1 x input, 6.6-47kΩ (switchable in 3 stages). 2 x outputs, 'more than 5kΩ'
ii. A/DA STD-1 - Stereo Tapped Delay: 1 x input, either 40kΩ or 1MΩ FET input (switchable). 2 x 'single-ended, 1/4 phone jacks, drives 600 ohm'.
iii. Dynacord S65 - Tube Tape Delay: 1 x input, 17 mV / 1MΩ. 1 x output, choice of either '0.5-1.0V / 250kΩ' or '10-50mV / 500kΩ'
iv. Telefunken Echomixer - 3-ch mixer w/Spring Reverb: 1 x input, choice of either '≤ 3mv / 2.5kΩ', '80mV / 47kΩ' or '500mV / 270kΩ'. 1 x output, 100mV / 100kΩ.
OK these are exactly what our dingo pup kit was made for with its balanced in to unbalanced and unbalanced to balanced amp on one pcb. With Fet input opamp you can set the input impedance by one resistor to 1Meg or More. This can also be done in compact form with our Tardigrade unbalanced to balanced kit for 8 channels to DB25 and the new palpigrade 8 channel Db25 kit will do the balanced to unbalanced part when it is available in about 1 to 2 weeks.

Re: Regurgitator kit Build Thread

Posted: Mon Mar 23, 2020 6:51 am
by MrMesh
Joe Malone wrote:OK these are exactly what our dingo pup kit was made for with its balanced in to unbalanced and unbalanced to balanced amp on one pcb. With Fet input opamp you can set the input impedance by one resistor to 1Meg or More. This can also be done in compact form with our Tardigrade unbalanced to balanced kit for 8 channels to DB25 and the new palpigrade 8 channel Db25 kit will do the balanced to unbalanced part when it is available in about 1 to 2 weeks.
Thanks Joe! I'll grab a Palpigrade/Tardigrade combo with a couple of Dingo Pups in that case. Do you foresee that the Coronavirus situation will delay the release of the Palpigrade?

Re: Regurgitator kit Build Thread

Posted: Mon Mar 23, 2020 12:07 pm
by Joe Malone
MrMesh wrote:
Joe Malone wrote:OK these are exactly what our dingo pup kit was made for with its balanced in to unbalanced and unbalanced to balanced amp on one pcb. With Fet input opamp you can set the input impedance by one resistor to 1Meg or More. This can also be done in compact form with our Tardigrade unbalanced to balanced kit for 8 channels to DB25 and the new palpigrade 8 channel Db25 kit will do the balanced to unbalanced part when it is available in about 1 to 2 weeks.
Thanks Joe! I'll grab a Palpigrade/Tardigrade combo with a couple of Dingo Pups in that case. Do you foresee that the Coronavirus situation will delay the release of the Palpigrade?
Should be ready to ship mid next week.

Main delay here at the moment is just lots of orders as everyone seems to want to build something while having to stay at home.

Re: Regurgitator kit Build Thread

Posted: Mon May 18, 2020 8:19 pm
by survivorsound
The unbalanced 75 ohm stereo line output on our RME MADI FX card has quite good specs, but outputs +13dBu for 0dBFS. We need it to match our other converters at +20 or +24dBu. In a recent test, we found that a standard THAT 1646 circuit used to send this output to our balanced patchbay sounded great in many ways, but affected the frequency response too much to be usable for monitoring purposes. I’d like to build the most transparent stereo Regurgitator possible and try that next.

I am lacking a Regurgitator schematic. On a bipolar 15V supply, can a LM4562 be used in place of the 5532 to enable direct coupling (a la the Tardigrade)? What would be the recommended build modifications in this case?

PS - We installed a Tardigrade in a Kepex rack and it is awesome.

Re: Regurgitator kit Build Thread

Posted: Tue May 19, 2020 9:46 am
by Joe Malone
survivorsound wrote:
Mon May 18, 2020 8:19 pm
The unbalanced 75 ohm stereo line output on our RME MADI FX card has quite good specs, but outputs +13dBu for 0dBFS. We need it to match our other converters at +20 or +24dBu. In a recent test, we found that a standard THAT 1646 circuit used to send this output to our balanced patchbay sounded great in many ways, but affected the frequency response too much to be usable for monitoring purposes. I’d like to build the most transparent stereo Regurgitator possible and try that next.

I am lacking a Regurgitator schematic. On a bipolar 15V supply, can a LM4562 be used in place of the 5532 to enable direct coupling (a la the Tardigrade)? What would be the recommended build modifications in this case?
Yes LM4562 or LME49720 will work in the regurgitator fine on +/-12v to +/-18v without any changes.

I have added the opamps to the regurgitator options on the webshop.
PS - We installed a Tardigrade in a Kepex rack and it is awesome.
Great to hear you have the Tardigrade working and like it :-)

Re: Regurgitator kit Build Thread

Posted: Tue May 19, 2020 11:52 am
by survivorsound
Thanks Joe! Are you able to share the schematic, or otherwise recommend what you’d try in terms of signal path with the LM4562/LME49720 in there?