A Friends DIY For Me
- Thread starter brad225
- Start date
brad225
Well-known member
- Thread Author
- #62
So, here we are a couple of weeks later and the issue is even more of a conundrum than ever.
Plus, I completely spaced out on my updates.
The zero out resistors got replaced and thought they worked much more accurately and quickly it didn't resolve the zero out problem with one side of the bias circuit.
After 2 weeks we heard back from ARC and found out that in the time frame that my amps were being built they had a shortage of resistors. The remedy was to change the way the circuitry worked with different parts but not show that on the schematics that were connected with the amps.
On the positive side one of the engineers that still works there remembered and they sent us free of charge the proper original parts that would have been in my amp. That change was only in the one amp of mine that is the problem not both.
We received the parts and Phil installed them and to our surprise or not ...... nothing changed. One side of the bias circuit still won't zero out.
Phil reached out with the latest information request but the person we are working with is out with Covid. So, we are having another delay. In the last 2 days I helped phil turn the amps upside down so he could re-solder all connections in the bias circuit. He has tested EVERY part in the problem bias circuit and it is an exact match to the amp that works perfectly.
While waiting, the only thing he can think of is, something under one of the 3, bias circuit tube sockets is an issue. There are traces in the board that have nothing to do with the bias circuit that run under the sockets. I ordered new ceramic sockets today and he will destroy and remove the old ones and see if there is something under one that might be a problem.
He actually asked me to order 6, and he would change them in the other amp so both amps will be exactly the same.
I am so fortunate to have a friend that is this smart and challenged by trying to solve a problem. He has admitted a couple of times that this, is the most complicated issue he has ever faced. I have told him more than once, if you get to the point you have had enough, I totally understand.
I suggested to Phil that he asked the intermediary he works through at ARC, if we paid his hourly rate could Phil speak directly with the engineer to work through this. He liked the idea, but, we will see if they will allow this to happen.
So that is where it stands today.
On my side, in the repayment column. I have started working on the bass speaker towers for Phils system to go with the panels I previously built for his line array speakers. They will also match the subwoofer box I built a few years ago.
Plus, I completely spaced out on my updates.
The zero out resistors got replaced and thought they worked much more accurately and quickly it didn't resolve the zero out problem with one side of the bias circuit.
After 2 weeks we heard back from ARC and found out that in the time frame that my amps were being built they had a shortage of resistors. The remedy was to change the way the circuitry worked with different parts but not show that on the schematics that were connected with the amps.
On the positive side one of the engineers that still works there remembered and they sent us free of charge the proper original parts that would have been in my amp. That change was only in the one amp of mine that is the problem not both.
We received the parts and Phil installed them and to our surprise or not ...... nothing changed. One side of the bias circuit still won't zero out.
Phil reached out with the latest information request but the person we are working with is out with Covid. So, we are having another delay. In the last 2 days I helped phil turn the amps upside down so he could re-solder all connections in the bias circuit. He has tested EVERY part in the problem bias circuit and it is an exact match to the amp that works perfectly.
While waiting, the only thing he can think of is, something under one of the 3, bias circuit tube sockets is an issue. There are traces in the board that have nothing to do with the bias circuit that run under the sockets. I ordered new ceramic sockets today and he will destroy and remove the old ones and see if there is something under one that might be a problem.
He actually asked me to order 6, and he would change them in the other amp so both amps will be exactly the same.
I am so fortunate to have a friend that is this smart and challenged by trying to solve a problem. He has admitted a couple of times that this, is the most complicated issue he has ever faced. I have told him more than once, if you get to the point you have had enough, I totally understand.
I suggested to Phil that he asked the intermediary he works through at ARC, if we paid his hourly rate could Phil speak directly with the engineer to work through this. He liked the idea, but, we will see if they will allow this to happen.
So that is where it stands today.
On my side, in the repayment column. I have started working on the bass speaker towers for Phils system to go with the panels I previously built for his line array speakers. They will also match the subwoofer box I built a few years ago.
brad225
Well-known member
- Thread Author
- #63
After I ordered the new ceramic tube sockets, Phil proceeded with the prep for the installation.
I received the sockets on Tuesday and took them up to him. He lives about 45 minutes away. He had removed the 3 sockets from each amp. Cleaned up and re-soldered any place that looked questionable on the traces where the sockets mount.
He also found ground loops under 2 sockets on each amp. He eliminated the ground loops was ready for the install. He asked if I was going to stay as he was going to do it immediately. I could not stay so, I left and he commenced.
By the time I was arriving home he called to say they made no difference in the problem amp and the amp that was problem free was, still exactly that, working perfectly.
He said, he was going to remove all of the parts from the bias circuit and retest them. He would also check all of the traces to be sure there were no issues. He said he was going to sleep on it and start in the morning.
We spoke in the morning and he said he thought through the process he had preformed with the parts ARC had sent to correct the non-published circuit change they had told us about.
He said he was convinced that the problem still had to do with the change ARC had made and the parts were still not correct.
He started with the part of the circuit that controlled the positive + voltage going to the zero adjust resistor we had replaced. It was always to high. He removed one of the resistors and lowered the value. The result was it lowered the starting point voltage closer to where it should be to start the adjustment with the adjustable resistor.
He pulled that resistor he put in and added a different value resistor and this time the starting value was correct and the zero adjust resistor was able to do it's job and "0" out the voltage on the positive + side.
From there he moved to the negative - side and changed the resistors until he got to the proper starting value. With that the negative - zero adjust resistor was able to zero out and it appears the amps are complete and ready to come home.
That was a lot of time, work, and frustration due to a non published schematic change and then sending the wrong parts for the repair.
When Phil finished it, and the amp worked properly this afternoon he called and was so excited he could hardly contain himself. I told him that, I was happier for him than I am for myself to be getting my amps back.
I am praying this saga is truly over for both of us.
I jokingly said to him. What if the changes that were made makes me not like the sound of the amps anymore?
I assured him that would not be an issue and he agreed.
Hopefully the only addition to the thread will be to confirm that the amps sound amazing and they are better than new.
I received the sockets on Tuesday and took them up to him. He lives about 45 minutes away. He had removed the 3 sockets from each amp. Cleaned up and re-soldered any place that looked questionable on the traces where the sockets mount.
He also found ground loops under 2 sockets on each amp. He eliminated the ground loops was ready for the install. He asked if I was going to stay as he was going to do it immediately. I could not stay so, I left and he commenced.
By the time I was arriving home he called to say they made no difference in the problem amp and the amp that was problem free was, still exactly that, working perfectly.
He said, he was going to remove all of the parts from the bias circuit and retest them. He would also check all of the traces to be sure there were no issues. He said he was going to sleep on it and start in the morning.
We spoke in the morning and he said he thought through the process he had preformed with the parts ARC had sent to correct the non-published circuit change they had told us about.
He said he was convinced that the problem still had to do with the change ARC had made and the parts were still not correct.
He started with the part of the circuit that controlled the positive + voltage going to the zero adjust resistor we had replaced. It was always to high. He removed one of the resistors and lowered the value. The result was it lowered the starting point voltage closer to where it should be to start the adjustment with the adjustable resistor.
He pulled that resistor he put in and added a different value resistor and this time the starting value was correct and the zero adjust resistor was able to do it's job and "0" out the voltage on the positive + side.
From there he moved to the negative - side and changed the resistors until he got to the proper starting value. With that the negative - zero adjust resistor was able to zero out and it appears the amps are complete and ready to come home.
That was a lot of time, work, and frustration due to a non published schematic change and then sending the wrong parts for the repair.
When Phil finished it, and the amp worked properly this afternoon he called and was so excited he could hardly contain himself. I told him that, I was happier for him than I am for myself to be getting my amps back.
I am praying this saga is truly over for both of us.
I jokingly said to him. What if the changes that were made makes me not like the sound of the amps anymore?
I assured him that would not be an issue and he agreed.
Hopefully the only addition to the thread will be to confirm that the amps sound amazing and they are better than new.
brad225
Well-known member
- Thread Author
- #64
Their home for the foreseeable future.
A nephew helped me move the amps to my second floor listening room yesterday.
With company for the last 2 days I started re-assembling the system this afternoon.
The worst part was getting the NAS, Sonictransporter, Ultrarendu, Playback Designs I-stream and Mps5 to talk properly after being shut down for 4 months. The problem is always me remembering how to get them to see each other not them.
Anyway it just so happened Phil was at an audio club meeting this afternoon and our house is on his way home.
By the time company left, I cleaned up my mess, got everything organized in the music room and connected, Phil was at the door.
Sorry these thought and comments aren't necessarily in the best order.
We went upstairs and could only smile at seeing the amps finished and back in place. We turned on the pre and power amps and sat down for a new tubes new parts break-in listen session.
After only 5-10 minutes listening the sound had different characteristics than I was use to hearing. Even at that time there was a quietness that was different. More spacious with specific details of sounds I wouldn't think possible at that early stage.
With that in mind, I have previously experienced a difference between single ended and balanced cables.
I had used an amp from my HT at the beginning of not having my 610t's but didn't like the sound. At the 10 minute mark, I looked at the preamp and noticed that I had not changed it to BAL from SE. When I did the sound was almost 20% louder and the image was very noticeably wider and deeper.
I know the sound will make many changes in the hours ahead.
At the 50-60 hour point Phil will need to re-adjust the zero out resistors as the other new parts will change as they break in.
As the 1 1/2 hours I had ended you could hear more breath and detail in horns being blown. You could tell the difference that the tubes and new parts were starting to warm.
I had not expected was after 1 1/2 hours you could actually put your hand on the KT120 tubes and though they were very hot you would not burn yourself. Related to that is my normal AC setting in the room I used with the 6550 tubes was way to cold.
I'll hopefully post more coherent information as they break in further and the sound improves.
brad225
Well-known member
- Thread Author
- #66
So, here I am a few months later and 300 hours into breaking in all of the new parts.
It's ok Dave, your can make fun of my breaking in belief.
I'm stunned at the difference/improvement in the sound of what are virtually new amps. The clarity is not something that I would have thought could improve this much. The size of the sound stage has moved wider and deeper than the previous version.
Small details in the music such as string vibration and the sound of a plucked string are clearly present. Not that it exists on all music but it is much more noticeable than previously showed when it does. Low-end is much more pronounced that I had experienced. I could ramble on but I will leave it with my opening comment that the sound is stunning.
If any of you get near Tampa and want some seat time to listen just reach out to me.
I did also choose to eliminate the 8m interconnects by moving 1/2 of the front end equipment to the front of the room. This allowed me to run 8m fiber optic from the previous location to the front. This helped shorting the new DIY interconnects to 2m. Being able to purchase 2- 8m fiber cables for $18 was not all bad either.
This was also an improvement in the overall sound.
I did mean I had to DIY an 8m #10 power cable to run through the conduit to the front of the room so I could keep the existing power conditioning feeding the new location.
It's ok Dave, your can make fun of my breaking in belief.
I'm stunned at the difference/improvement in the sound of what are virtually new amps. The clarity is not something that I would have thought could improve this much. The size of the sound stage has moved wider and deeper than the previous version.
Small details in the music such as string vibration and the sound of a plucked string are clearly present. Not that it exists on all music but it is much more noticeable than previously showed when it does. Low-end is much more pronounced that I had experienced. I could ramble on but I will leave it with my opening comment that the sound is stunning.
If any of you get near Tampa and want some seat time to listen just reach out to me.
I did also choose to eliminate the 8m interconnects by moving 1/2 of the front end equipment to the front of the room. This allowed me to run 8m fiber optic from the previous location to the front. This helped shorting the new DIY interconnects to 2m. Being able to purchase 2- 8m fiber cables for $18 was not all bad either.
This was also an improvement in the overall sound.
I did mean I had to DIY an 8m #10 power cable to run through the conduit to the front of the room so I could keep the existing power conditioning feeding the new location.
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Barry
Member
Wow, what a journey! You are so lucky to have Phil work on things. One thing that surprises me is the ground loops he found and repaired that seemed to be part of the original design.
I am not a fan of ARC's resistors in some locations. I also own an ARC Ref 40, but found it to have just a little bit of veiling and very slight dryness that bothered me. I thought it was the 6H30s. A quick swap of a few of the resistors in the signal path with TX2575s (naked Z-foil Vishays) convinced me otherwise. VAC uses these sparingly in their latest designs with good results.
Oh, as you probably know, the SED Winged "C"s are a little nicer sounding than the Sovteks WEs in the REF40. You probably have quite a few good left overs from the 610!
This was a fun read with a very happy ending. Thanks!!!
I am not a fan of ARC's resistors in some locations. I also own an ARC Ref 40, but found it to have just a little bit of veiling and very slight dryness that bothered me. I thought it was the 6H30s. A quick swap of a few of the resistors in the signal path with TX2575s (naked Z-foil Vishays) convinced me otherwise. VAC uses these sparingly in their latest designs with good results.
Oh, as you probably know, the SED Winged "C"s are a little nicer sounding than the Sovteks WEs in the REF40. You probably have quite a few good left overs from the 610!
This was a fun read with a very happy ending. Thanks!!!
brad225
Well-known member
- Thread Author
- #70
Thanks Barry, Phil has casually glanced into the Ref 40 a few times and said "there are a few things we could change right away.
Soon after I purchased the 40, I changed to early RCA 6550As and it made a surprising improvement. That surprised me because, it was only in the power supply. I realize it all matters but I didn't expect the smoothness it brought.
Soon after I purchased the 40, I changed to early RCA 6550As and it made a surprising improvement. That surprised me because, it was only in the power supply. I realize it all matters but I didn't expect the smoothness it brought.