DC heater
Elevating the heaters to about 40V has done wonders on one of my headphone amps...definitely worth a try!
Oliver
Elevating the heaters to about 40V has done wonders on one of my headphone amps...definitely worth a try!
Oliver
buble_corp said:
That suggests two problems. First it says that you didn't use screened lead to the input of the 6SN7, secondly it suggests that the case isn't earthed. The case must be connected to mains earth. Depending on your system, the 0V of your HT should be connected to case (it probably should). The connection should be made at your star earth point.
power supply question
Hi, I'm looking to build "Franks ultimate tube preamp". Do you have a schematic for a choke version of your PS? I'm looking only to build the buffer or the later schematic that includes gain(I haven't decided yet). I think I'd like to stick with one ps with two chokes, one for each channel.
Could this be tweeked to work??
Hi, I'm looking to build "Franks ultimate tube preamp". Do you have a schematic for a choke version of your PS? I'm looking only to build the buffer or the later schematic that includes gain(I haven't decided yet). I think I'd like to stick with one ps with two chokes, one for each channel.
Could this be tweeked to work??
An externally hosted image should be here but it was not working when we last tested it.
Franks Ultimate Tube Preamp completed.
I just recently completed my build of this design and thought I'd post my pics, since this thread didn't have any completed pics posted. Still burning in, but sounds good...
If anyone is interested...I can post pics of the guts.
I just recently completed my build of this design and thought I'd post my pics, since this thread didn't have any completed pics posted. Still burning in, but sounds good...
If anyone is interested...I can post pics of the guts.
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I must admit, I'm always partial to internal shots, if it's not too much of a hastle.
Franks Preamp Internals
I just had a month off and really wanted to get going on this thing. I didn't have the attenuator nor the extension to operate it remotely at the time... so I layed out the case in the current format. For what I was going to use this for, I didn't think I would need to adjust it much. The location does keep the wire lengths short. This was my first attempt at P2P wiring and was rather fun to build. The case is made from left over Bella wood cherry flooring. Any generic flaws in the way I wired it? It's very quiet, no ground hum, so I gotta be pleased with that. What would be the tube of choice for the 12BH7A's? From what I've gathered it would be the black plate RCA's?
I just had a month off and really wanted to get going on this thing. I didn't have the attenuator nor the extension to operate it remotely at the time... so I layed out the case in the current format. For what I was going to use this for, I didn't think I would need to adjust it much. The location does keep the wire lengths short. This was my first attempt at P2P wiring and was rather fun to build. The case is made from left over Bella wood cherry flooring. Any generic flaws in the way I wired it? It's very quiet, no ground hum, so I gotta be pleased with that. What would be the tube of choice for the 12BH7A's? From what I've gathered it would be the black plate RCA's?
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Wiring question
More specifically, is there any benefit to using shielded cable from/to the input / output jacks? Because the runs are short, I didn't think it warranted it.
More specifically, is there any benefit to using shielded cable from/to the input / output jacks? Because the runs are short, I didn't think it warranted it.
Sorry. I thought this was a new thread. I didn't realize it was already 34 pages long! Too late to throw this monkeywrench in.
Hi,
Nice job, hope you enjoy the way it sounds.😎
Regarding shielded wire, no, you do not need it per se but it may still be beneficial in your case as you do not seem to use a metal box, correct?
My advise to you would be to keep both channels as symmetrical as possible and as short as need be.
Properly implemented star earthing may also put the noise floor down.
Cheers, 😉
Nice job, hope you enjoy the way it sounds.😎
Regarding shielded wire, no, you do not need it per se but it may still be beneficial in your case as you do not seem to use a metal box, correct?
My advise to you would be to keep both channels as symmetrical as possible and as short as need be.
Properly implemented star earthing may also put the noise floor down.
Cheers, 😉
I think I pretty much did this...
If you look at the first internal picture, the rectangular piece of wood at the bottom has a sheet of copper on the other side (which is not visible). The sheet of copper is the star earth. However on the amp side, I did group things together at a terminal board before running them to the star earth on the copper sheet. You think running these individually to the copper sheet would lower the noise floor?
Cheers, 😉
I am missing some information about how to connect the heaters to the main PSU. Any need for elevated potential?
The best info I could find is the above, but it is easy to miss in such a long (and nice) thread...
The best info I could find is the above, but it is easy to miss in such a long (and nice) thread...
Use one of these...(a separate transformer is used, actually I used two, one for each channel)
I used the 14V transformer version.
Preamp is dead quiet.
I used the 14V transformer version.
Preamp is dead quiet.
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Rolling tubes?
I just replaced the Amperex 0G3's with some Mullard gold pin 5651's. I'm noticing a significant improvement...is that possible? I would have thought rolling these tubes would have the least effect on sound quality.
I just replaced the Amperex 0G3's with some Mullard gold pin 5651's. I'm noticing a significant improvement...is that possible? I would have thought rolling these tubes would have the least effect on sound quality.
Hi,
It is definetely possible.
I noticed improvement in stereo imaging and a generally quieter background, more air as well.
My favourites (as usual) are the RCA 561As.
Cheers, 😉
It is definetely possible.
I noticed improvement in stereo imaging and a generally quieter background, more air as well.
My favourites (as usual) are the RCA 561As.
Cheers, 😉
I am like flabbergasted. I cannot believe the improvement these tubes made. I already loved this preamp... but we are talking a whole 'nother level now...
Hi,
Should you ever want to take this preamp to the limit of what I feel is possible with this circuitry, let me know.
I should reread the entire thread so I know at what level I left it but I know of several ways to further improve it to the point of becoming a looking glass of the original recording.
A goal I set for myself many years back and to which I dedicated countless hours to achieve.
Anno 2010 I still believe there's still untapped potential left to be discovered from the depths of the basic circuitry.
So much so that it will continue to put digital playback of music where it belongs: the butcher shop...
Anyhow, thank you for making the effort to build this humble circuit.
Enjoy life, it's too short for mediocracy. 😉
Cheers,
Should you ever want to take this preamp to the limit of what I feel is possible with this circuitry, let me know.
I should reread the entire thread so I know at what level I left it but I know of several ways to further improve it to the point of becoming a looking glass of the original recording.
A goal I set for myself many years back and to which I dedicated countless hours to achieve.
Anno 2010 I still believe there's still untapped potential left to be discovered from the depths of the basic circuitry.
So much so that it will continue to put digital playback of music where it belongs: the butcher shop...
Anyhow, thank you for making the effort to build this humble circuit.
Enjoy life, it's too short for mediocracy. 😉
Cheers,
I would love to pursue further improvements...give me the weekend to write up my exact build....and I'll get back to you.