I finished mine enough to listen to it. I am still waiting on the source extension shaft and coupler to arrive, and I need to find knobs that fit.
First the numbers. Maybe someone can tell me if these seem ballpark correct. I am using 15 volt 25 VA transformers.
+- 22.8 V before the capMx
+- 19.8 V at the Melbourne board attachments.
339 mv at the Melbourne test points.
While I will wait a week before giving sound quality impressions, after a few hours I have nothing to complain about. It currently sounds rather pleasant and a little forgiving, but I am running it into the Pass M2 which is also rather pleasant and forgiving. It sounds more tube-like than solid state, in that there is no thin sound in any manner, but maybe a touch forward. The unit is absolutely quiet regarding hum and buzz, which is always a nice surprise when you first listen to your new build.
I am using a 50k TOCOS pot. I don't have anything of lower impedance on hand at the moment.
Thanks to those who have answered my questions during the build. Now I'm off to find an LED for the front panel.
First the numbers. Maybe someone can tell me if these seem ballpark correct. I am using 15 volt 25 VA transformers.
+- 22.8 V before the capMx
+- 19.8 V at the Melbourne board attachments.
339 mv at the Melbourne test points.
While I will wait a week before giving sound quality impressions, after a few hours I have nothing to complain about. It currently sounds rather pleasant and a little forgiving, but I am running it into the Pass M2 which is also rather pleasant and forgiving. It sounds more tube-like than solid state, in that there is no thin sound in any manner, but maybe a touch forward. The unit is absolutely quiet regarding hum and buzz, which is always a nice surprise when you first listen to your new build.
I am using a 50k TOCOS pot. I don't have anything of lower impedance on hand at the moment.
Thanks to those who have answered my questions during the build. Now I'm off to find an LED for the front panel.
Attachments
Sorry about that -yours must have been the orders before I switched to 3M Blue Tape.
Mineral spirits / paint thinner takes off the goop well. Followed by alcohol and then wash with warm water and dish detergent.
Spray WD-40 on the PCBs let it sit a minute or so and then wipe with a paper towel to remove the residue. Then wash with soap and warm water.
Good as new
@redjr, TboneAK and aljordan
Wow! 3 Yarra’s born within a few days, it’s nice to see more built Yarra’s out in the wild.
Nice work Fellas
Thank you Vunce. Your shopping cart for both the Yarra and the Melbourne boards saved me a lot of time and frustration. Also, to the person who uploaded the annotated BOM spreadsheet, that was very helpful as well.
I am thinking of building the Korg boards next, but I am curious if I can set the boards appropriately for the proper distortion signature without some sort of distortion analyser. Will the boards work fine with the 15 Volt transformers?
Alan
The Korg works fine with 15v trafo as it has a voltage regulator to drop the voltage to 3.3v for the filament. You only need to use a DVM to set the operating point - the plate voltage needs to be adjusted via the trim pot to be 12.0v (IIRC).
The YARRA Preamplifier/HPA for Melbourne DB Group Buy
I want to give a quick shout-out to asuslover (Gabe) He was gracious enough to sell me a Yarra case and the board to go with it. Now I have an extra set of boards! Best thing is they were well packaged and got here in one day??
If he had charged shipping I would think he walked across the street and put them in my box. Also, thanks to X for putting the word out here.
Thanks Gabe
Props,
JT
If he had charged shipping I would think he walked across the street and put them in my box.
Also, thanks to X for putting the word out here. Thanks Gabe
Props,
JT
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I want to give a quick shout-out to asuslover (Gabe) He was gracious enough to sell me a Yarra case and the board to go with it. Now I have an extra set of boards! Best thing is they were well packaged and got here in one day??
If he had charged shipping I would think he walked across the street and put them in my box.
Thanks Gabe
Props,
JT
Thank you!
I will regret this transaction in a couple of weeks .....
But have fun,
Gabe
Should the plate voltage be adjusted (trim pot) prior to soldering in the 6P1 'tube' and then re-adjust after it's in? Or, does it matter? In any event, it's rated at 80V and there's no way it'll even come close to that!
Just want to make sure everything is set properly beforehand.My Amp died
Sad morning... After a couple weeks testing my Yarra pre(Mel DBs) on my bench without any issues, I decided to take it to my listening room and pair it with my prized and gorgeous sounding First One (FO) amp. This amp has been functioning fine for over 2 years and been a delight to listen to.
I powered everything up in a sequence that would minimize any pops. Gradually turned up the volume and nothing! I doubled checked all cabling and even swapped out a couple different ones to the Yarra and to the amp. Still nothing. After a few minutes and several different attempts, I got a very, very slight/subtle whiff of burned electronics. The top of the Yarra was off and nothing looked amiss. The LEDs were glowing and there was no obvious odor coming from it.
So, I decided to swap out the FO power amp with my V4H I had built over the summer. Hooked up my DAC, powered everything up, opened roon and music started flowing. So obviously, the problem was with my FO amp. So, curious as I am, I took the FO to my bench and took the top off. Out came the full stench of burned electronics! On first glance and sniff, the smell was the strongest around the output devices of the left channel module. I will have to remove them to check the underside of the PCB for any charred evidence.
I will say, I'm NOT blaming anything on the Yarra. However it is curious that the Yarra was the only new variable in my system. At this point I have not had any time to dismantle the FO and start checking things out. I do know that over the past 2 years, other owners/builders of the FO amp have had issued with the modules failing and the vendor has been silent and basically refused any support. The amp modules are no longer available. So, if it was time for my modules to fail, the timing with adding a new preamp is questionable. Odd. I had no DC voltage present on the output of the Yarra while it was on my bench.
My question is... Is there any inherent design of the Yarra or Melbourne DBs that would have in some way contributed to this unfortunate event? I'm very meticulous with my builds and always double-check everything before powering up and testing. I had no idea something like this would happen simply by plugging in a new preamp. Not saying it did.
I will say, the pre has way to much gain for my sources and needs to be reduced. I barely have to turn the volume past zero before I'm blasted with sound from the V4H amp. I believe X mentioned in another thread that R118 needs to be changed to 12K to lower it by 6dB. Can anyone validate this from their own experience, or offer another value for even more gain reduction?
Sad day for my First One amp.
Sad morning... After a couple weeks testing my Yarra pre(Mel DBs) on my bench without any issues, I decided to take it to my listening room and pair it with my prized and gorgeous sounding First One (FO) amp. This amp has been functioning fine for over 2 years and been a delight to listen to.
I powered everything up in a sequence that would minimize any pops. Gradually turned up the volume and nothing! I doubled checked all cabling and even swapped out a couple different ones to the Yarra and to the amp. Still nothing. After a few minutes and several different attempts, I got a very, very slight/subtle whiff of burned electronics. The top of the Yarra was off and nothing looked amiss. The LEDs were glowing and there was no obvious odor coming from it.
So, I decided to swap out the FO power amp with my V4H I had built over the summer. Hooked up my DAC, powered everything up, opened roon and music started flowing. So obviously, the problem was with my FO amp. So, curious as I am, I took the FO to my bench and took the top off. Out came the full stench of burned electronics! On first glance and sniff, the smell was the strongest around the output devices of the left channel module. I will have to remove them to check the underside of the PCB for any charred evidence.
I will say, I'm NOT blaming anything on the Yarra. However it is curious that the Yarra was the only new variable in my system. At this point I have not had any time to dismantle the FO and start checking things out. I do know that over the past 2 years, other owners/builders of the FO amp have had issued with the modules failing and the vendor has been silent and basically refused any support. The amp modules are no longer available. So, if it was time for my modules to fail, the timing with adding a new preamp is questionable.
Odd. I had no DC voltage present on the output of the Yarra while it was on my bench.My question is... Is there any inherent design of the Yarra or Melbourne DBs that would have in some way contributed to this unfortunate event? I'm very meticulous with my builds and always double-check everything before powering up and testing. I had no idea something like this would happen simply by plugging in a new preamp. Not saying it did.
I will say, the pre has way to much gain for my sources and needs to be reduced. I barely have to turn the volume past zero before I'm blasted with sound from the V4H amp. I believe X mentioned in another thread that R118 needs to be changed to 12K to lower it by 6dB. Can anyone validate this from their own experience, or offer another value for even more gain reduction?
Sad day for my First One amp.