I have Two Sources that are both produced with Valves.
One is a Valve Input>Output Phonostage.
One is a Valve Output DAC.
I am having later this year my Mono Block 845 Power Amps converted to being a Balanced Amplifier.
I am also changing tack on my Korg B1 build and it will be produced as Balanced Design.
A Second Board has been ordered.
I have not raised questions about the following until now.
The Phonostage is in a sealed box, almost impossible to gain access within, without being destructive.
Are there options available to produce a off board Balanced Output for the Phono Stage to operate as Balanced ?
The DAC is an easier to work with Device, as the Internal Workings are easy to access.
What are the difficulties to be met to successfully convert the DAC to Balanced Output ?
Any thoughts shared will be very appreciated.
One is a Valve Input>Output Phonostage.
One is a Valve Output DAC.
I am having later this year my Mono Block 845 Power Amps converted to being a Balanced Amplifier.
I am also changing tack on my Korg B1 build and it will be produced as Balanced Design.
A Second Board has been ordered.
I have not raised questions about the following until now.
The Phonostage is in a sealed box, almost impossible to gain access within, without being destructive.
Are there options available to produce a off board Balanced Output for the Phono Stage to operate as Balanced ?
The DAC is an easier to work with Device, as the Internal Workings are easy to access.
What are the difficulties to be met to successfully convert the DAC to Balanced Output ?
Any thoughts shared will be very appreciated.
With a trafo you can get a balanced signal from unbalanced.
But if you convert the 845 to balanced probably you will install a trafo from unbal to bal.
If it is a s.e.; different if it is p-p.
So you don't need any other stuff in the first case.
Walter
But if you convert the 845 to balanced probably you will install a trafo from unbal to bal.
If it is a s.e.; different if it is p-p.
So you don't need any other stuff in the first case.
Walter
You are better off using an INPUT bridging transformer with 1:1 ratio on the preamp side. Long cable from phono to transformer and very short cable from transformer to preamp or amp. Do you even use a preamp? Typically they are 10k:10k designs, like Jensen or Cinemag, so the impedance is high enough or easier load for the source impedance. 10K ohms should be high enough for many tube output with cathode follower. It's best to know what kind of output circuit is inside that phono stage. If the output capactor is sized up to drive a specific load and if the impedance is lower than expected you will get premature bass roll-off. That's why I don't recommend an output transformer tacked onto the phono preamp, as that type of transformer typically is low impedance or step-down transformers and you will lose gain.
to Directdriver
if he convert the 845 in balance mode probably use a trafo.
So he doesn't need any other stuff
Walter
if he convert the 845 in balance mode probably use a trafo.
So he doesn't need any other stuff
Walter
We do not have any information how the balanced conversion is made. He could be using a differential input stage. We don't even know if the 845 amp is single ended or push-pull. And we don't even know if he uses a preamp or not.
I do agree using an input transformer is the best way. And if he does use a transformer, what is the input impedance, 600Ω, 10K, or higher? As we know some tube stages have a hard time driving low impedance load. Does the phono stage even have a cathode follower with a bigger enough output capacitor?
Perhaps OP needs to elaborate more on his system or the circuit of the 845 amp.
As I wrote in post 2
He has two stuff with tubes so the trafo eventually he will use can be 10k as primary and secondary center tapped due the coupling capacitor and (maybe) not a lower Zout of the source circuit
Walter
He has two stuff with tubes so the trafo eventually he will use can be 10k as primary and secondary center tapped due the coupling capacitor and (maybe) not a lower Zout of the source circuit
Walter
Thank You for the responses these are very much appreciated.
My EE Skill are very wanting so all works are to be carried out by a Professional.
I am attempting to learn the Next Stages for the equipment.
The 845's are to have a 10K:10K Line Tranx and 3 Pin Female XLR's added.
All the Options on Tranx's were discussed an this Value was put forward for its ability to Drive the Mono's Direct.
The Mono's also have a inbuilt Balance Control, so a Off Board VC is not required.
I have used the Source Direct to the Mono's, as well as use,
a Traditional Design Valve Pre', Passive Stepped Att', Slagle AVC, and a Pass KB1.
The KB1 as a Pre' is extremely satisfying when used on this system.
I am still trying to grasp the requirement for the SUT > Phon' and DAC.
Is it a case of installing Female XLR Sockets to each device, or is there an additional requirement to be carried out on the circuits ?
Again Thank You for the replies offered.
My EE Skill are very wanting so all works are to be carried out by a Professional.
I am attempting to learn the Next Stages for the equipment.
The 845's are to have a 10K:10K Line Tranx and 3 Pin Female XLR's added.
All the Options on Tranx's were discussed an this Value was put forward for its ability to Drive the Mono's Direct.
The Mono's also have a inbuilt Balance Control, so a Off Board VC is not required.
I have used the Source Direct to the Mono's, as well as use,
a Traditional Design Valve Pre', Passive Stepped Att', Slagle AVC, and a Pass KB1.
The KB1 as a Pre' is extremely satisfying when used on this system.
I am still trying to grasp the requirement for the SUT > Phon' and DAC.
Is it a case of installing Female XLR Sockets to each device, or is there an additional requirement to be carried out on the circuits ?
Again Thank You for the replies offered.
Whne you say 10k:10k do you know the model of trasformer?
In my opinion you haven't to add anything for phono and dac. Just a switch, on 845 amp, to select the proper wire configuration
Walter
In my opinion you haven't to add anything for phono and dac. Just a switch, on 845 amp, to select the proper wire configuration
Walter
The Tranx that has been discussed at present is a Hammond Design.
It is not set in stone but has been presented as having a useful range and the part offered a guidance on a price.
The EE is booked full of Projects until September.
This leaves myself a little time to better understand the changes to be made to the Amp's.
It is not set in stone but has been presented as having a useful range and the part offered a guidance on a price.
The EE is booked full of Projects until September.
This leaves myself a little time to better understand the changes to be made to the Amp's.
The Mono Block Power Amp's when being designed had the option of a Un-balanced/Single End Input Only.
When the Amp's were complete the discussion with the EE covered that the Option of Unbalanced and Balanced as a Input would have created a more flexible usage and would have made controlling any earth noise easier to achieve.
In the past couple of years a Hum was present that I was not able to remove, then COVID come along and I was unable to have a visitor to assist with the investigation.
I am now in a position to have a Balanced Input and in my mind this will assist me with controlling any earth noise.
The EE has also produced for me a device that has removed the Earth Noise and the quietness has been very well received.
I see this device as great inclusion, but a Temporary Measure whilst I am on a waiting list for the EE.
When the Amp's were complete the discussion with the EE covered that the Option of Unbalanced and Balanced as a Input would have created a more flexible usage and would have made controlling any earth noise easier to achieve.
In the past couple of years a Hum was present that I was not able to remove, then COVID come along and I was unable to have a visitor to assist with the investigation.
I am now in a position to have a Balanced Input and in my mind this will assist me with controlling any earth noise.
The EE has also produced for me a device that has removed the Earth Noise and the quietness has been very well received.
I see this device as great inclusion, but a Temporary Measure whilst I am on a waiting list for the EE.