@ItsAllInMyHead this is for you guys in the States cause you don't have 98 at the pumps, sorry about that. Here a label on the tank would say 98. Also the US measures octane levels differently and 98 is something like 93 in the US. More than factual here.
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I tried using those. My set of two had a difference of 0.7dB between channels, and was clearly audible as a tonal imbalance. Have now permanently shifted to using dedicated differential receiver chips.
Abstractly speaking (and I am not attributing this to trickster), BUT, would it make sense to run the single from a SE output preamp (or other source) that does not have a balanced out, to a SE input on an amplifier which is not truly balanced in its internal topology, by using an specially made and dedicated XLR jack to plug, with signal + routed to pins 2, signal ground routed to pins 3, and shield only on pins 1, with the following connections within the DIY-constructed source and amp: signal+ of source to pin 2 and signal in to amp from pin 2; and pin 1 connected on one side only (likely the preamp/source) to chassis (not signal ground). The concept being that the shield is only tied to chassis and bleeds off any EMI/RFI to the chassis ground (and being tied only on one side does not contribute to the possibility of creating a ground loop); signal ground is not polluted by the EMI/RFI in the shield.
That is interesting - a tonal difference and not just a level difference. Do you have any ideas why transformers would induce such a change (e.g., capacitance differences due to manufacturing tolerances)?
Here, this seems to me an interesting solution, expensive (over 250 euros) but interesting, then we should deal with the switching problem, (manual or automatic), but let's deal with one problem at a time.
@tricksters could you please let us know what your source to the F5T would be (name, brand, model, picture)?
Also, I still don't see any advantage to the balanced input of your single ended F5T unless you have long cable run (say more than 10m; or at least 5m), which you said you don't have.
On the contrary, if you would build your F5T balanced, then you are only looking for a balanced input (as well at best for a balanced source to it). But you said you don't do this.
A balanced stereo amp would have 4 channels inside. The X150 you mention (and Mark Levinson gear) don't only have XLR inputs, they are build balanced, i.e. 4 channels inside for a stereo device.
Make sure you understand the difference:
Also, I still don't see any advantage to the balanced input of your single ended F5T unless you have long cable run (say more than 10m; or at least 5m), which you said you don't have.
On the contrary, if you would build your F5T balanced, then you are only looking for a balanced input (as well at best for a balanced source to it). But you said you don't do this.
A balanced stereo amp would have 4 channels inside. The X150 you mention (and Mark Levinson gear) don't only have XLR inputs, they are build balanced, i.e. 4 channels inside for a stereo device.
Make sure you understand the difference:
- Single ended gear with balanced connectors (implemented properly using transformers or chips) are typically studio or PA devices, used to overcome long cable runs. Those are 2 channels inside for stereo.
- Balanced gear with balanced connectors (straight, no transformers or any summing chips of any kind) are typically highest-end gear, double the cost and space (4 full channels inside for stereo).
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Weird DC offset on F5 turbo v2 build: 0.68mV dc offset on the left channel speaker output with 250mV bias voltage across T2 and T3 on each output board and even more worrying is 1.45V dc offset on the right channel speaker output with 250mV bias voltage across T2 and T3 on those output boards. I can't figure out what's going wrong here. Any suggestions?
I have cascoded the Jfets with Tip31 and Tip32 transistors. I have also paralleled the JFets (q1.1 and Q1.2 and Q2.1 and Q2.2) This is to help protect the JFets from the higher rail voltage I'm running.
I have 35V+/- DC on the main PSU for the rail voltages and I have a 600VA Antek 6224 transformer as the power transformer.
I have cascoded the Jfets with Tip31 and Tip32 transistors. I have also paralleled the JFets (q1.1 and Q1.2 and Q2.1 and Q2.2) This is to help protect the JFets from the higher rail voltage I'm running.
I have 35V+/- DC on the main PSU for the rail voltages and I have a 600VA Antek 6224 transformer as the power transformer.
Hello dpogorman,
the DC-offset at speakeroutput depends on various factors:
pot3 set to midposition?
You have well matched N-channel and p-channel - MosFets?
Your bias (voltage over the bias resistors) will always be different from the N-channel-MosFets to the P-channel-MosFets. That is pretty normal.
Also if you have well matched Mosfets.
You bias your N-channel and P-channel (over trimpot P1 and P2) to get the correct overall bias and the lowest DC-offset at speakeroutput.
Therefor you will read slightly lower or higher amounts of voltage over the bias resistors on the N-channel or the P-channel. Get you DC- offset
at speakeroutput below 50mV - below 10mV is reallly good.
Cheers
Dirk
the DC-offset at speakeroutput depends on various factors:
pot3 set to midposition?
You have well matched N-channel and p-channel - MosFets?
Your bias (voltage over the bias resistors) will always be different from the N-channel-MosFets to the P-channel-MosFets. That is pretty normal.
Also if you have well matched Mosfets.
You bias your N-channel and P-channel (over trimpot P1 and P2) to get the correct overall bias and the lowest DC-offset at speakeroutput.
Therefor you will read slightly lower or higher amounts of voltage over the bias resistors on the N-channel or the P-channel. Get you DC- offset
at speakeroutput below 50mV - below 10mV is reallly good.
Cheers
Dirk
@elwood625, what are the specs of your transformer secondaries? Something around 35V and 15A?
I am debating Whether to convert my 5Tv3 monoblocks to balanced. Transformers have 35v secondaries, giving me 47v rails. My caps are rated at 63v. I understand that balanced will double my voltage swing. Does this mean 94v rails (clearly too high)? Do I need higher rated caps? Or is each side (n/p) of the monobloc still seeing only 47v ? Not sure I fully understand and hoping someone can explain. Thanks!
Alex
Alex
Perfect. I was spec'ing 800VA toroids with 35VAC/14.93A secondaries per balanced mono block. About 190mm in diameter and 90mm hight.