@Nelson Pass sorry for bothering you, any news on that balanced version you mentioned you were working on? Thank you!
DIY Front End 2022
- Thread starter Nelson Pass
- Start date
I been listening to FE2022 (V0R1) a few days now an I really like it, perfect performance. Built mostly from older project parts. I’m using it as gain stage between Turtle Iron Pumkin and F4 with 10dB gain, which is more than I need. The pots are fixed at 750 ohm. I had no need to use them so resistors will take their place as soon I get the motivation to open it.
Nice! Some more porn, please. 2U chassis?
What xfmr are you using, and what value resistors did you settle on for the UBIB?
Was thinking of exactly this approach to try the FE2022 as a pre - with one of Lenny’s VCX that I can remove from a project I have on a shelf. Need to catch up on the UBIB GB/availability.
The way I rationalise it, the accumulating number of Papa Projects is wholly justified by the fun times spent on them. Despite pointed comments along the lines of ‘…just how many boxes do you actually need?’
What xfmr are you using, and what value resistors did you settle on for the UBIB?
Was thinking of exactly this approach to try the FE2022 as a pre - with one of Lenny’s VCX that I can remove from a project I have on a shelf. Need to catch up on the UBIB GB/availability.
The way I rationalise it, the accumulating number of Papa Projects is wholly justified by the fun times spent on them. Despite pointed comments along the lines of ‘…just how many boxes do you actually need?’
The inside is more interesting than the boring outside, bad porn. The FE is done with j113 from Store kit but it is tempting to open the octet unobtainum I found in my stash. Ultra BiB is set on +/-24. I have used UBiB in several projects. AVC is ZM-Turtle in Iron Pumkin .
edit: 3U chassi to match height of Turtle. UBiB resistors is long forgotten but I can check if you are cu enough.
Number of boxes should always be to many.
edit: 3U chassi to match height of Turtle. UBiB resistors is long forgotten but I can check if you are cu enough.
Number of boxes should always be to many.
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I haven't seen any 48V Dual Mono FE 22 built yet. Over 2 months with only one channel operating and power failures at house level. Rebuilt now 4 times and will not put back together until volume is corrected or just use on other PASS amps. Had to discard the one channel and use up the spare the Store allows Greedy Boyz to buy at a time. It is severly cobbled together to get both channels up.
6L6 stated no problem with loudness on his MOFO's.
It has the highest R3R4 for 10 Gain. It is not enough.
Can I install 150K resistors or is this it? As it stands volume is less then public movie house level.
Thanks H.
6L6 stated no problem with loudness on his MOFO's.
It has the highest R3R4 for 10 Gain. It is not enough.
Can I install 150K resistors or is this it? As it stands volume is less then public movie house level.
Thanks H.
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Installed in series another 100K on R3/R4 one channel. "Improvement" if there is, not enough.
Above post by
Then stacking another FE 22 in series before MoFo an option???
This should not be. The speakers are under stressed.
Or build more BA-3 pre's with max gain and stack???
The legacy amps from NAD and Sony have no problem driving all the speakers.
An important factor is the voltage output of the source. If the source can output 1.4Vrms, the DIY FE 2022 at 10x will output 14Vrms. 14Vrms out of the MoFo into 8R is 24.5W, which is at the upper end of maximum power output from a Big MoFo.
Most sources should be able to output 1.4Vrms.
Most sources should be able to output 1.4Vrms.
I'm using the computer on all trials. Using lossless files. Flac, and mp3. All amps are on the computer output set at max. Legacy amps are on the computer, both have internal pre's. I can run and test all at the same time.
The pot on the pre FE 22 is at max. I control volume at the computer.
The link for the MoFo's is below:
https://www.diyaudio.com/community/threads/build-this-mofo.313649/post-7404931
...and I can't figure what it is.
MoFo is Dual Mono, 2 amps per bed.
Tested MoFo's with Korg B1. Same problem.
Could try splitting the NAD and driving the MoFo on the Nad Preamp.
Get the high gain BA-3 pre's running which will take more time.
Does anyone know what drives the output on the MoFo?
tonyEE,
11 ain't cutting it.
Wasted so much time with this when I should be building 4 Zen Iron Pre's.
11 ain't cutting it.
Wasted so much time with this when I should be building 4 Zen Iron Pre's.
The max gain of the IronPre is actually somewhat less than that of the standard BA2022 FE (x4 vs x10)
What voltage are your Mofo's running at?
What voltage are your Mofo's running at?
The MoFo is a follower amp with no gain stage. Gain must be provided by a preamp/front end. If your source has low voltage output you may need a preamp and a front end, or a higher gain preamp/front end.
The B1 Korg is only capable of outputting approximately a few volts before the distortion gets too high. At 5Vrms, the distortion is approximately 6 or 7%.
The B1 Korg is only capable of outputting approximately a few volts before the distortion gets too high. At 5Vrms, the distortion is approximately 6 or 7%.
Just under the 2.5A recommended.
6L6 mentioned the Pass FE 22 should drive the MoFo, as it has his, quite well.
The computer has about the best V source I have to test.
I have run two BA-3 preamps, not enough gain. One FE 22 V0, not enough gain.
Used the Korg just to try. The only other thing is split the NAD and run MOFO off that Pre. If I can.
Pass FE is at the highest gain by the chart. In desperation mode installed double the resistence on R3, R4 on one channel. Difference? Not much.
I will attempt running Pass FE on NAD
When all that fails measure MOFO and Pre's output with Sine Wave. Finish high gain BA-3, make yet another board for BA-3.
When MOFO boards arrive in store, build yet another to compare to the 2 pair then convert them to Sub use..........
Thanks all for your help. I alone can break any amp in new and unique ways!!! 
Yes, but this source ,computer, has never not driven any other pre or amp I've put after it. With any speaker that I have. It will destroy any speaker turned up.
I will be measuring everything after a few more analog tests, to compare.
Thanks H.