Wayne's BA 2018 linestage

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#1,822
Hicoco said:
Just finish my adapted Salas UltraBib with on/off, tested with a 2X20V , 12Va 229B40 Hammond, will use it for the new UGC muse preamp with 2X28V, 12Va 229B56 Hammond.
I have cpl of board left, may be that will be good with BA 2018. if interested PM.
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PJN said:
That's what I used on my build, very nice combo.
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I still have two spare board left for free, you just pay for shipping.
 

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#1,823
Robin De Wolf said:
So if my offset is stable I do not need to worry about my soldering skills affecting performance, am I right?

Btw, does anyone know how this circuit does balanced to se. Can I make it work with dc on both balanced signals cancelling out?

I would like to try my second board with my dddac bal to se.

Input much appreciated!
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Soldering skills art very important always. If your offset is stable, you did something right!

Russellc
 
#1,824
Extreme_Boky said:
I use balanced, current-out DAC as well. The voltage on positive-out and negative-out pins is around + 2.5V DC. I tried feeding the analog-out signals without the capacitors, straight to Aleph J used in balanced mode (AND without that 1uF cap on -IN !!!). It sounded superb, BUT... you have to pay strict attention to NOT turn the amplifier first. In other words, I had to be certain the DAC was turned ON first, wait a few seconds, and then the amplifier was turned ON. The sound was incredible, however, there was a great chance that I was going to damage my speakers if I wasn't paying STRICT attention.

So, my suggestion is to use 4 high-quality caps between the DAC current out pins, and the next stage (especially if the next stage is a DC amplifier).

Mind you, once the DAC was ON (no caps at the output), and the Alaph J was ON (DC coupled throughout) for a few minutes, the DC offset at the output was hovering between +20mV and -20mV... the sound was incredible.

Later on, I decided to save my Dynaudios by installing 4 Auricaps XO caps on each DAC-out feed, which did not really change the sound much... maybe the depth a bit, but it was still good and (reasonably) safe.

The issue with (DIY, right...?? no relays!!) DAC's is that when they are turned ON, one side may reach +2.5V quicker... and if the amp is on, you'll see the bass cone movement. Now, if the AMP is DC coupled, that difference will also get the full gain as well... and that is quite dangerous. Unfortunately, even if you use the capacitors, they will charge unevenly during that first second, and the DC difference will STILL be present at the amplifier input.

But, did I mention already a few times that the sound was fantastic..?

If you know what you are doing... go for it. I tried to highlight a few risks above, so...

You could try everything on a bench; load the amp with 50W / 8-ohm resistors, remove the caps, use the oscilloscope (record function? so that you can capture what happens when you turn things ON...)... and see if what you observe is satisfactory to you, or not. This is really the only way. Otherwise, you will not know for sure.
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Thanks Boky, however, I do not want the circuit (Dac nor preamp) to pass dc. Initially I used a Neurochrome Buffer to convert the dac's bal to se, which worked fine, "cancelling" DC on the outputs: Vout = (Vin+ + DC) - (Vin- + DC) = Vin+ - Vin-.

The Wayne linestage does not seem to work this way ( I am not skilled enough to read how this works from the schematic). Is there a way to make this work?

@ Russellc, thanks! I learned smd soldering making a Muses volume control (by Meldano).
 
#1,829
#1,832
6L6 said:
Balanced in to SE is simple... the input can accept balanced with zero changes. That’s why it has IN+/IN-/GND.

If your source has any DC you should probably add some caps.
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Initially I thought you meant adding caps after the dac but I could add caps at the output of the linestage instead, right? I will not be using any volume control on the input that could cause popping. (I will only use it as bal to se conversion with small amount of gain).
 
#1,833
John Broskie's "Front Panel" volume control/source switcher is a nice improvement over an Alps pot I had been using, as many of you would not be surprised to hear. I had assumed that it was a dual mono volume control like I had on my long-gone (and missed) Superphon and Audible Illusions preamps. But the Front Panel uses shunt and series stepped attenuation, so the left-side switch is for "coarse" volume settings, while the center switch "fine tunes" the volume. The right-hand switch switches inputs. Aside from sound quality, the big benefit for me was that it made wiring up a volume/input switcher a cinch. But I can see why those who strongly prefer remote control would hate it.

My power supply was a tad marginal for the task (taken from a Sugden phono preamp), so I tried out the Glassware power supply suggested by 6L6 and that was an improvement too.

Now my Wayne-designed BA 2018 preamp into the F4 sounds as good as I could ever want. Thanks for your generosity, Wayne! And of course, thanks be to 6L6 for his patient help, and to Mark for pointing out to me a simple way to increase the signal out into a hungry F4 (post 1233).
 
#1,834
soldersmoker said:
John Broskie's "Front Panel" volume control/source switcher is a nice improvement over an Alps pot I had been using, as many of you would not be surprised to hear. I had assumed that it was a dual mono volume control like I had on my long-gone (and missed) Superphon and Audible Illusions preamps. But the Front Panel uses shunt and series stepped attenuation, so the left-side switch is for "coarse" volume settings, while the center switch "fine tunes" the volume. The right-hand switch switches inputs. Aside from sound quality, the big benefit for me was that it made wiring up a volume/input switcher a cinch. But I can see why those who strongly prefer remote control would hate it.

My power supply was a tad marginal for the task (taken from a Sugden phono preamp), so I tried out the Glassware power supply suggested by 6L6 and that was an improvement too.

Now my Wayne-designed BA 2018 preamp into the F4 sounds as good as I could ever want. Thanks for your generosity, Wayne! And of course, thanks be to 6L6 for his patient help, and to Mark for pointing out to me a simple way to increase the signal out into a hungry F4 (post 1233).
Click to expand...

I’ve used Broskie’s A3 for a couple builds. It is an excellent choice for great sound on a budget. My only issue with it is the cheap Alpha brand switches. I usually get a lot of noise when switching. It goes away when i find the desired attention.
 
#1,835
andynor said:
So I decided on Gaz’s PSU. Looking forward to this.

I need tips on a fitting volume pot, source selector, on/off switch and headphone input for this preamp. I’ll be using the Galaxy 388 chassis. Anyone?
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I'm using the same power supply. It works great! For source selector you could try the Muffsy: Muffsy Relay Input Selector - Kit from muffsy on Tindie Very happy with it, and it's straightforward to set up. Check out post: #1711

Trond
 
#1,836
tbaashus said:
I've more or less finished building my BA2018! Turned it on for the first time yesterday. I am always a little surprised when things work straight away. I was very much in doubt that my soldering skill were up to these tiny SMD transistors.

For this build I used a power supply from fellow diyaudio member Gaz2613. Very easy to put together and with excellent instructions here: Building an improved adjustable Bi-Polar Power Supply! (Updated: 14th Aug 2020) – audiosy.net

I'm also using a Muffsy Relay Input Selector. It supports four inputs, and has mute, standby function, indicator leds and remote control. I added support for motorised volume pot myself. This one is also very easy to build: https://www.muffsy.com/muffsy-relay-input-selector-4.html

I found a nice chassis on eBay which suited my needs perfectly (although it has some alternative spelling on the input selector knob).

Some remaining things to do: Find a sensible way to mount the IR sensor and I will rewire the IEC socket so that L is switched and fused instead of N.
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tbaashus said:
I'm using the same power supply. It works great! For source selector you could try the Muffsy: Muffsy Relay Input Selector - Kit from muffsy on Tindie Very happy with it, and it's straightforward to set up. Check out post: #1711

Trond
Click to expand...

Hi,
Do you have some info regarding the chassis?

Abe
 
#1,839
soldersmoker said:
John Broskie's "Front Panel" volume control/source switcher is a nice improvement over an Alps pot I had been using, as many of you would not be surprised to hear. I had assumed that it was a dual mono volume control like I had on my long-gone (and missed) Superphon and Audible Illusions preamps. But the Front Panel uses shunt and series stepped attenuation, so the left-side switch is for "coarse" volume settings, while the center switch "fine tunes" the volume. The right-hand switch switches inputs. Aside from sound quality, the big benefit for me was that it made wiring up a volume/input switcher a cinch. But I can see why those who strongly prefer remote control would hate it.

My power supply was a tad marginal for the task (taken from a Sugden phono preamp), so I tried out the Glassware power supply suggested by 6L6 and that was an improvement too.

Now my Wayne-designed BA 2018 preamp into the F4 sounds as good as I could ever want. Thanks for your generosity, Wayne! And of course, thanks be to 6L6 for his patient help, and to Mark for pointing out to me a simple way to increase the signal out into a hungry F4 (post 1233).
Click to expand...

Is this the one you use?

FrontPanel

Seems this both takes care of both signal selection and volume control. Also, I don’t have to worry about channel volume differences sometimes associated with Alps pots. I have three hand milled knobs from Modushop, one big and two small ones. This bord should fit the bill! Does it do Waynes LS justice?

Only thing missing now is IEC inlet, RCAs and AC switch. I’ll probably go with a filtered IEC inlet from Mouser, and some fitting RCAs from the same source. Any good and not so expensive robust RCA inputs fron Mouser you would recommend buying?

So the plan as of now, is avout the following:

388 Galaxy chassis with UMS bottom plate
Waynes Linestage
Gaz’s PSU
Frontpanel attenuator and selector from Glassware
AC switch from Glassware
IEC RFI+EMI filtered from Mouser
Milled knobs from Modushop

RCA inputs/outputs: What to choose?

Signal cables internally: cat 6 twisted pair, or should I go shielded? What to choose, and where to find? I do not have a lot of S-video and other cables lying around. I want to keep it cheap and simple, so I favour TYPE of cable over materials used. IOW coax, cat 6, or what might fit the bill.

Anything I havent thought about?

Cheers,
Andreas
 
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#1,840
andynor said:
cat 6 twisted pair, or should I go shielded?
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I recommend twisted, unless your place is plagued with whatever a wire can pick up.

Working with shielded cable for internal connections is a plague for itself and often not necessary...

(Me, for the sake of aesthetics, also have a look at the looks of stuff like wires etc., but this is another shoe not to be discussed [emoji2958][emoji4])
 
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