RCA Outputs for Impasse ?
Hello Everyone : Im very interested in building this preamp ! Being on a limited budget things take alot longer as I have to save for each project ect... I am currently building a F4 and it may be some time before I can construct another. My question is can the Impasse be constructed using rca's for an output ? This will allow me to listen while saving to build another ect...
Hello Everyone : Im very interested in building this preamp ! Being on a limited budget things take alot longer as I have to save for each project ect... I am currently building a F4 and it may be some time before I can construct another. My question is can the Impasse be constructed using rca's for an output ? This will allow me to listen while saving to build another ect...
SY, Thank-you for the quick reply ! As for the gain, would it be to high for my intended use ? Will a single F4 amp have a problem when using the Impasse as described with SE outputs ? 
I have an old Cary AE-3 preamp with a gain of 20 that I had thought to use. It uses 2 > 6SN7's in a SE Class-A style ! It sounds very good but also has its limits ect...
I have an old Cary AE-3 preamp with a gain of 20 that I had thought to use. It uses 2 > 6SN7's in a SE Class-A style ! It sounds very good but also has its limits ect...
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SY, Again thank's this is the preamp I speak of > http://www.audioxpress.com/reviews/media/GA400HA2.pdf Mine is a newer version with a improved Psu ect... I have not as of yet completed my F4 meanwhile I currently use an older Denon amp with the AE-3 and a Sony DVD player for source ect...
Impasse rebuild
OK ,
I have an issue at power up with the right channel whistling for a few seconds and then working fine. Also I was a little rushed during the initial build and in re-soldering some connections I burnt a few of the pads on my board. So I ordered a new board from Jack and will perform a overhaul.The board I have is not correctly routed for the Jenson transformers, I was wandering if the replacement board will have the same issue?
Bill
OK ,
I have an issue at power up with the right channel whistling for a few seconds and then working fine. Also I was a little rushed during the initial build and in re-soldering some connections I burnt a few of the pads on my board. So I ordered a new board from Jack and will perform a overhaul.The board I have is not correctly routed for the Jenson transformers, I was wandering if the replacement board will have the same issue?
Bill
I am finally getting around to finishing my PSU, man it's been too long.
I have one question though. I plan on using two separate heater windings, one for each tube. These windings don't have a center tap, so I was planning on making on for each heater out of a pair of 100 resistors. My question is, can I then tie both of these center taps together and then connect that to my voltage divider to elevate the heaters, or do I need two voltage dividers, one for each heater.
Seems like a single reference is okay, but I didn't know if there was something else at play that I wasn't thinking about. Here's hoping that I can knock this out over the holiday!
I have one question though. I plan on using two separate heater windings, one for each tube. These windings don't have a center tap, so I was planning on making on for each heater out of a pair of 100 resistors. My question is, can I then tie both of these center taps together and then connect that to my voltage divider to elevate the heaters, or do I need two voltage dividers, one for each heater.
Seems like a single reference is okay, but I didn't know if there was something else at play that I wasn't thinking about. Here's hoping that I can knock this out over the holiday!
excellent!
I have one more unrelated question. When people typically measure a balanced output preamp such as this, for say distortion, or just hooking a scope up to the output to make sure it's functioning, do people typically people measure across the balanced output, ignoring the ground?
I noticed you can buy an unwired version of this:
Neutrik - Audio - Circular Adapters - NA2MBNC
I was thinking about picking one up and wiring the positive output to the pin, and the negative output to the shell. Then I could plug that into my scope, or if I can ever figure out how to use my HP distortion analyzer, etc. In fact, in this case of using the HP, I could put another one on the input, and the transformer should take care of unbalanced to balanced conversion and I should be able to measure end-to-end.
The default wiring of these is 2 hot, and 1 and 3 to ground, that's why I'd pick up the unwired version.
Are my assumptions somewhat sane?
I have one more unrelated question. When people typically measure a balanced output preamp such as this, for say distortion, or just hooking a scope up to the output to make sure it's functioning, do people typically people measure across the balanced output, ignoring the ground?
I noticed you can buy an unwired version of this:
Neutrik - Audio - Circular Adapters - NA2MBNC
I was thinking about picking one up and wiring the positive output to the pin, and the negative output to the shell. Then I could plug that into my scope, or if I can ever figure out how to use my HP distortion analyzer, etc. In fact, in this case of using the HP, I could put another one on the input, and the transformer should take care of unbalanced to balanced conversion and I should be able to measure end-to-end.
The default wiring of these is 2 hot, and 1 and 3 to ground, that's why I'd pick up the unwired version.
Are my assumptions somewhat sane?
Each time I see a ref to Pin 1, I point out the following reference:
Pin 1 Revisited
Pin 1 Revisited
g,day all
first let me say thankyou to all for making this pre availiable to diy,ers (especially jakinnj i have built some great amps thanks to your store)
i have just bought the assembled impasse kit on youre site and am wondering if i also need to purchase the power supply kit as well ?
i will be using it to drive 2x f4 in mono balanced configuration
regards sheafer
first let me say thankyou to all for making this pre availiable to diy,ers (especially jakinnj i have built some great amps thanks to your store)
i have just bought the assembled impasse kit on youre site and am wondering if i also need to purchase the power supply kit as well ?
i will be using it to drive 2x f4 in mono balanced configuration
regards sheafer
Unfortunately, owing to the floods here I have been unable to provide the assembled Impasse. I've got other stuff going on which necessitates a lot of travel for the next several months, so (while you will see me on DIYAUDIO) I am only going to sell the boards at my cost. I also have some Cinemag 10K:10K which I will dispense at cost.
That being said, I reworked the boards to amend the error I'd made with the Depletion MOSFETs and straightened out the layout a bit. The results are pretty good. In single ended mode with 10K load the THD% with 2.828V out is 0.0037%. (SY said in the article: "better than 0.01%). I found that Electro-Harmonix worked best, but YMMV. I also substituted 1u/400V on the output as I used the rest of my 0.47u/400V on another project.
That being said, I reworked the boards to amend the error I'd made with the Depletion MOSFETs and straightened out the layout a bit. The results are pretty good. In single ended mode with 10K load the THD% with 2.828V out is 0.0037%. (SY said in the article: "better than 0.01%). I found that Electro-Harmonix worked best, but YMMV. I also substituted 1u/400V on the output as I used the rest of my 0.47u/400V on another project.
An externally hosted image should be here but it was not working when we last tested it.
I was able to simultaneously analyze each channel. One was run balanced, the other single-ended, 1kHz in, level adjusted for 2.83V out:
This is far from an ideal test setup -- the boards are just sitting on the workbench without benefit of chassis, etc. Pretty darned good, I would say.
An externally hosted image should be here but it was not working when we last tested it.
This is far from an ideal test setup -- the boards are just sitting on the workbench without benefit of chassis, etc. Pretty darned good, I would say.
