Thank you, I'm glad we finally agree. So are you going to update the spec?
I know the APx585 does not use transformers on the inputs nor the outputs, I've opened one up. It would be interesting to know if the 2-channel versions APx525 and 555 are any different.
Comments on say a guitar preamp
I was wondering what you thought about a THAT1200 chip set for 18V and a small PCB that could fit into a bass guitar (or electric)?
The sound guys at church dislike my passive guitar due to mid level pasive pickups. They of course are running long cables to the mixer. I'm sure there is some attenuation there as well.
Dave
I was wondering what you thought about a THAT1200 chip set for 18V and a small PCB that could fit into a bass guitar (or electric)?
The sound guys at church dislike my passive guitar due to mid level pasive pickups. They of course are running long cables to the mixer. I'm sure there is some attenuation there as well.
Dave
You'd need the THAT1646 driver rather than the THAT1200 receiver. You could potentially integrate that into the guitar. Maybe add a bit of gain to bring the signal out of the noise early in the chain. I don't know how well that'd work with the mixer, though. You could ask the sound guys...
The THAT Driver can be configured with gains of +6 dB and higher.
Tom
The THAT Driver can be configured with gains of +6 dB and higher.
Tom
passive filter and volume control config
Hello Tom,
I am about to order your board for a stereo preamp and had one question. I use a passive line level filter to compensate, in part for my open baffle speakers on the low end. The configuration is reflected in the following page -- where you will see that the line level option wants to feed an impedance of >50k. I don't use the HF compensating cap.
Passive Line Level Baffle Diffraction Step Compensation
I have a stereo stepped, resistive volume/balance attenuator from John Boskie that is nominally 100k. Should I place the filter before the attenuator or between the attenuator and your unit?
Thanks,
Skip
Hello Tom,
I am about to order your board for a stereo preamp and had one question. I use a passive line level filter to compensate, in part for my open baffle speakers on the low end. The configuration is reflected in the following page -- where you will see that the line level option wants to feed an impedance of >50k. I don't use the HF compensating cap.
Passive Line Level Baffle Diffraction Step Compensation
I have a stereo stepped, resistive volume/balance attenuator from John Boskie that is nominally 100k. Should I place the filter before the attenuator or between the attenuator and your unit?
Thanks,
Skip
I'd go: source -> filter -> volume control -> THAT Driver. This sequence will ensure that the filter is fed with a low source impedance and loaded with 100 kΩ, thus work as intended.
Tom
Tom
Hi Tom,
I have a question about possible use for THAT Line Driver.
I am thinking of upgrading (replacing) my DAC by building a Twisted Pear Buffalo III.
I would run the BIII in multi-channel mode, with single ended outputs. BIII says "Up to 8 channels of outputs can be used in current-output or voltage-output mode (depends on output stage used)"
So Twisted Pear makes the IVY-III or Legato I/V output stages.
Since I already own three Neurochrome THAT Line Drivers, would they be a good substitute to use instead of Ivy or Legato?
Seems to me that if DAC outputs in voltage mode, that the function of the output stage is simply to add some gain,... or maybe I just don't understand.
Sorry, I'm not trying to put you on the spot, nor ask you to comment on Twisted Pear products. I'm just trying to understand if my idea would be a good application for using THAT Line Driver.
I have a question about possible use for THAT Line Driver.
I am thinking of upgrading (replacing) my DAC by building a Twisted Pear Buffalo III.
I would run the BIII in multi-channel mode, with single ended outputs. BIII says "Up to 8 channels of outputs can be used in current-output or voltage-output mode (depends on output stage used)"
So Twisted Pear makes the IVY-III or Legato I/V output stages.
Since I already own three Neurochrome THAT Line Drivers, would they be a good substitute to use instead of Ivy or Legato?
Seems to me that if DAC outputs in voltage mode, that the function of the output stage is simply to add some gain,... or maybe I just don't understand.
Sorry, I'm not trying to put you on the spot, nor ask you to comment on Twisted Pear products. I'm just trying to understand if my idea would be a good application for using THAT Line Driver.
If the DAC has current output, you'll need an I/V (current-to-voltage) converter. You can build a differential I/V stage or take the output of a single-ended I/V converter and run it into a THAT Driver for a differential output.
If the DAC has voltage output, you can take its output directly to a THAT Driver if you'd like to convert to differential output.
Some DACs are current output but many integrate the I/V converter into the DAC chip. You'll have to look at TP's documentation to figure out what they do.
Hope this helps.
Tom
If the DAC has voltage output, you can take its output directly to a THAT Driver if you'd like to convert to differential output.
Some DACs are current output but many integrate the I/V converter into the DAC chip. You'll have to look at TP's documentation to figure out what they do.
Hope this helps.
Tom
Once again Tom has provided an excellent service, another "THAT Driver" is born...
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Well, I am close to completion -- all the hardware is mounted and the signal connections are made. Just a bit of power supply wiring to go.
I am using, at least initially, a toroid that is way, way larger than needed. It's a good output voltage and was sitting on the shelf. It has dual primaries to allow 120 or 240 VAC input. I could parallel them which would enable maximum current, but, because it's so oversized, just one primary should be fine. Do you have any guidance. If it buzzes, I'll get a smaller, appropriate transformer right away.
Thanks,
Skip
I am using, at least initially, a toroid that is way, way larger than needed. It's a good output voltage and was sitting on the shelf. It has dual primaries to allow 120 or 240 VAC input. I could parallel them which would enable maximum current, but, because it's so oversized, just one primary should be fine. Do you have any guidance. If it buzzes, I'll get a smaller, appropriate transformer right away.
Thanks,
Skip
I have a 25VA 15V transformer, connected to a Power86. It's enough to run Three THAT Line Driver boards (I have a six channel setup). I ordered it from Antek for $11 plus shipping. Works great.
If your transformer has dual 120/240 or 115/230 V primaries, I'd parallel them for 115/120 V operation. I don't see any reason not to.
Each THAT Driver board only draws a few VA from the transformer. If you budget for 5 VA per board on a 2x18 V transformer, you'll be fine.
Tom
Each THAT Driver board only draws a few VA from the transformer. If you budget for 5 VA per board on a 2x18 V transformer, you'll be fine.
Tom
Didn't see a thread for the THAT receiver, so I will ask here.
I have an unbalanced input amp I am building. If I want a balanced input connection I could add a THAT receiver. If I would like to run an unbalanced signal into the amp would it be better to use a RCA to XLR cable or add a switch to switch between XLR and RCA ins. All my equipment is currently unbalanced, but I am slowly converting things over to using XLRs so during the transition I will need to use unbalanced cables and connections.
I have an unbalanced input amp I am building. If I want a balanced input connection I could add a THAT receiver. If I would like to run an unbalanced signal into the amp would it be better to use a RCA to XLR cable or add a switch to switch between XLR and RCA ins. All my equipment is currently unbalanced, but I am slowly converting things over to using XLRs so during the transition I will need to use unbalanced cables and connections.
With the Power86 board can you feed it with 15V AC or 18V AC secondaries off a transformer to get the V DC you need to run the THAT driver and receiver?
Sorry. I didn't see your post until now. I need to renew my thread subscriptions, it seems.
If you're building a "THAT Preamp" based on my boards, I suggest running single-ended to the volume control. I.e. RCA -> input selector -> volume control -> THAT Driver. Or THAT Receiver -> Input selector -> Volume control -> THAT Driver for a differential i/o.
A Power-86 and a 2x18 V transformer will be perfect for powering the THAT boards. Another option would be the SMPS-86, though at 2x60 W it's a bit overkill for the application. It would offer a turnkey solution with international mains voltage capability, though.
Tom
If you're building a "THAT Preamp" based on my boards, I suggest running single-ended to the volume control. I.e. RCA -> input selector -> volume control -> THAT Driver. Or THAT Receiver -> Input selector -> Volume control -> THAT Driver for a differential i/o.
A Power-86 and a 2x18 V transformer will be perfect for powering the THAT boards. Another option would be the SMPS-86, though at 2x60 W it's a bit overkill for the application. It would offer a turnkey solution with international mains voltage capability, though.
Tom
I have use for the driver boards in a preamp/DAC I am building. DAC board and preamp board are both single ended. All the inputs are also single ended. So I will put the driver boards after the preamp boards. I have a 2x15V transformer that I could use to feed a Power-86 board. Probably would need 4 boards.
I also have a 4-channel amp that I am building. The amp channels are single ended so I would need 2 Receiver boards to add XLR capability to the amps. I will have a 2x18V transformer in the amp that I could connect to a Power-86 board.
I decided to standardize on XLR out from the preamp to XLR in on all the amps. I could have 12 to 14 channels of amplification if I run 3ways on the mains and run 5.2 or 5.4 surround.
I also have a 4-channel amp that I am building. The amp channels are single ended so I would need 2 Receiver boards to add XLR capability to the amps. I will have a 2x18V transformer in the amp that I could connect to a Power-86 board.
I decided to standardize on XLR out from the preamp to XLR in on all the amps. I could have 12 to 14 channels of amplification if I run 3ways on the mains and run 5.2 or 5.4 surround.
2x15 VAC should give you about ±19-20 V rectified. That's perfect.
I have tons of the RX MONO boards in stock. I think I'm down to four RX boards and one TX board. I have more of those coming from the manufacturer next week. The new boards will be pretty blue but otherwise be identical to the current crop of boards.
Tom
I have tons of the RX MONO boards in stock. I think I'm down to four RX boards and one TX board. I have more of those coming from the manufacturer next week. The new boards will be pretty blue but otherwise be identical to the current crop of boards.
Tom
The passive preamp board has two single ended outputs that are basically just split. So I could take the two stereo single ended outputs from the preamp and run each of them through a TX board. I take it that that is preferable to splitting the balanced outputs after the TX board (using one TX board to drive 4 channels instead of 2).