Hi Dirk - The tape method 6L6 posted was the only one that worked with any consistency for me. It worked perfectly.
Thanks!
-Glen
Thanks!
-Glen
The tape method described by 6l6 is great...even easier than the bamboo skewer method I used the first time.🙂
Russellc
Russellc
Glen- that is looking great! Will be even better when complete. 😀
bmdduck - You could run the BA2018 from the regulators of the Pearl 2, there’s plenty of excess power capacity. I’d still build it in two chassis, with the raw PSU outboard. Adding the linestage, switching and volume would be easy.
bmdduck - You could run the BA2018 from the regulators of the Pearl 2, there’s plenty of excess power capacity. I’d still build it in two chassis, with the raw PSU outboard. Adding the linestage, switching and volume would be easy.
Thanks 6L6 - I didn't realize I could use the power from from the Pearl.
I bought all the parts for the linestage - including the TubeCad dual regulated PS (18V), to I will probably build it that way first, and the Pearl boards and second chassis for the PS later.
I bought all the parts for the linestage - including the TubeCad dual regulated PS (18V), to I will probably build it that way first, and the Pearl boards and second chassis for the PS later.
Hi,
A few questions about the preamp: 🙂
1. what are the input/output impedance? (I have 33k and 47k/50k input impedance power amps)
2. why the choice of A1220/C2690 in some builds, instead of original A992/C1845?
3. do we have to change other components, like R11/R12, to use the TO-126 devices?
4. the TO-126's are faster (fT) than the TO-92 ones, anything to worry about?
5. TO-92's have higher beta (gain), again, any component to compensate it or...
6. ... can we just use either options?
Probably you have already discussed all of them, but I can't find the # posts.
Thanks.
A few questions about the preamp: 🙂
1. what are the input/output impedance? (I have 33k and 47k/50k input impedance power amps)
2. why the choice of A1220/C2690 in some builds, instead of original A992/C1845?
3. do we have to change other components, like R11/R12, to use the TO-126 devices?
4. the TO-126's are faster (fT) than the TO-92 ones, anything to worry about?
5. TO-92's have higher beta (gain), again, any component to compensate it or...
6. ... can we just use either options?
Probably you have already discussed all of them, but I can't find the # posts.
Thanks.
Attachments
Last edited:
1) R18 makes input impedance about 100K, Output is an ohm or two.
2) They can drive headphones.
3) See attached schematic.
4) Not really, again see attached.
5) Re: 3, 4. 🙂
6) Sure! But stability is up to you. I know somebody has tried something else large with good results.
2) They can drive headphones.
3) See attached schematic.
4) Not really, again see attached.
5) Re: 3, 4. 🙂
6) Sure! But stability is up to you. I know somebody has tried something else large with good results.
Thanks 6L6!
So, the use of A1220/C2690 is for headphones only?
Last question: recommended value for volume/attenuator?
So, the use of A1220/C2690 is for headphones only?
Last question: recommended value for volume/attenuator?
Last edited:
Big output devices work great for line as well.
Attenuator is more about your sources than the preamp. If you have nothing with a tube output, use 10K to 25K.
Attenuator is more about your sources than the preamp. If you have nothing with a tube output, use 10K to 25K.
For the "Big Outputs", Toshiba TTA004B,Q and TTC004B,Q work very well also.
I used 15R @ 1 Watt for R11, R12 and put the R23/C4 RC element in again after looking at the square waves with my 'scope. (Don't remember if I saw overshoot without the RC element, or just plain too much bandwidth (-3dB at more than 2 MHz))
Regards, Claas
I used 15R @ 1 Watt for R11, R12 and put the R23/C4 RC element in again after looking at the square waves with my 'scope. (Don't remember if I saw overshoot without the RC element, or just plain too much bandwidth (-3dB at more than 2 MHz))
Regards, Claas
to Karl vd Berg #1872
Hello Karl,
I used the Toshiba TTA/TTC004B in my outputstage with excellent results.
I matched them very well (see my posts #1162 and #1146 in this thread).
It sounds excellent as a preamp as well as a headphoneamp with the 'big outputstage'. Very recommended! The big Fairchilds are also very good devices.
I built two versions of Waynes linestage. My ones are running on +-24V rails.
Greets
Dirk
Hello Karl,
I used the Toshiba TTA/TTC004B in my outputstage with excellent results.
I matched them very well (see my posts #1162 and #1146 in this thread).
It sounds excellent as a preamp as well as a headphoneamp with the 'big outputstage'. Very recommended! The big Fairchilds are also very good devices.
I built two versions of Waynes linestage. My ones are running on +-24V rails.
Greets
Dirk
A question on Chassis ground
I have read that a good practice of of implementing chassis ground is using a CL60 in series to the ground. The PE (protective earth) will also be connected to this point.
I can't find the CL160 that I had in my parts box. 🙁
An alternative method that I have come across is to use a resistor, typically of 10R value? I see that 6L6 has used a resistor here, however not sure of the value :
https://www.diyaudio.com/forums/pass-labs/329240-waynes-ba-2018-linestage-91.html#post6020330
I have also attached part of the pic shared by 6L6, showing the grounding scheme and the resistor for reference.
I have 10R 5 watts resistors that I can use if that is a good choice. Any advice on this is welcome
I have read that a good practice of of implementing chassis ground is using a CL60 in series to the ground. The PE (protective earth) will also be connected to this point.
I can't find the CL160 that I had in my parts box. 🙁
An alternative method that I have come across is to use a resistor, typically of 10R value? I see that 6L6 has used a resistor here, however not sure of the value :
https://www.diyaudio.com/forums/pass-labs/329240-waynes-ba-2018-linestage-91.html#post6020330
I have also attached part of the pic shared by 6L6, showing the grounding scheme and the resistor for reference.
I have 10R 5 watts resistors that I can use if that is a good choice. Any advice on this is welcome
Attachments
Wayne used a bridge in his design for the Pearl 2 phono preamp.
https://www.passdiy.com/pdf/PEARL 2.pdf
https://www.passdiy.com/pdf/PEARL 2.pdf
Hello. I need a new project, and a backup preamp will fit the bill. iIm gonna renew my aleph P1.7 soon, so this one would be of interest.
I'm thinking of doing a linestage/headphone combo. What would be the sweetspot voltagewise? +/-18V, or would a +/-24V supply be a better option? And is there a easy to get regulated PSU board out there that someone could recommend?
I'm thinking of doing a linestage/headphone combo. What would be the sweetspot voltagewise? +/-18V, or would a +/-24V supply be a better option? And is there a easy to get regulated PSU board out there that someone could recommend?
The more I mess with voltages the more I don’t think it matters. Use what you can get or are most interested in.
Lots And lots of PSU out there, eBay, pmillett (look in the LR phono project, it’s kinda hidden) Mark Johnson has a nice PCB that works, Muffsy.com, tubecad.com, Silent Switcher, and on and on. The world is your oyster.
Lots And lots of PSU out there, eBay, pmillett (look in the LR phono project, it’s kinda hidden) Mark Johnson has a nice PCB that works, Muffsy.com, tubecad.com, Silent Switcher, and on and on. The world is your oyster.