Hi Nicoch
So - you recommend using shinkoh as a stepped resistor-potmeter instead of a ldr? Yeah, maybe I will give that a try - if there is enough space where my old 10k pot is residing. I doubt it will fit as it is - for the moment. Or maybe there is a way of making the pot a 4-5 steps resistor changer. I mainly use The B1 through the SIT with 3-4 positions = 40%, 50%, 70-80% Throttle. Denpending on the level that the CD,DSD or Flac/Wav is recorded. So if it weak in SPL(Pirates-Rickie Lee Jones) - I can use full speed without overly strong output and distortion. But if it is heavily recorded(Ashes and Fire - Ryan Adams) - I can use maximum 50% before it is too heavy in my room.
So maybe a good relay with 4-5 Shinkoh or other good resistors so one can choose a different output = 2/10 - 4/10 - 5/10 - 9/10?
How about this solution?
Best
Olav
PS Olav I mean for ldr series resistor ...btw I put all over the place
So - you recommend using shinkoh as a stepped resistor-potmeter instead of a ldr? Yeah, maybe I will give that a try - if there is enough space where my old 10k pot is residing. I doubt it will fit as it is - for the moment. Or maybe there is a way of making the pot a 4-5 steps resistor changer. I mainly use The B1 through the SIT with 3-4 positions = 40%, 50%, 70-80% Throttle. Denpending on the level that the CD,DSD or Flac/Wav is recorded. So if it weak in SPL(Pirates-Rickie Lee Jones) - I can use full speed without overly strong output and distortion. But if it is heavily recorded(Ashes and Fire - Ryan Adams) - I can use maximum 50% before it is too heavy in my room.
So maybe a good relay with 4-5 Shinkoh or other good resistors so one can choose a different output = 2/10 - 4/10 - 5/10 - 9/10?
How about this solution?
Best
Olav
Hi again All
Hi Nicoch, Juanitox and Vdi_Nenna + whoever...
In the postbox 2 minutes ago - arrived my 2 1 uF Obbligato, my 4 big AMRG 220 ohm resistors and my 47 ohm AMRG(Amtrans).
Have to get my soldering-station ready and start doing some changeover - on the B1 in this step!
The 47 on The SIT must wait till the kids are off to school(family need some support also)
And the sound is now so good - that I`m nearly hesitating to start???
Well, off we go!
Best
Olav
Hi Nicoch, Juanitox and Vdi_Nenna + whoever...
In the postbox 2 minutes ago - arrived my 2 1 uF Obbligato, my 4 big AMRG 220 ohm resistors and my 47 ohm AMRG(Amtrans).
Have to get my soldering-station ready and start doing some changeover - on the B1 in this step!
The 47 on The SIT must wait till the kids are off to school(family need some support
also)And the sound is now so good - that I`m nearly hesitating to start???
Well, off we go!
Best
Olav
Hi Olav,
I have the same problem. We won't know until the changes are made.
I'm going to give my amp a month or more before making any changes.
Been listening every night. Problem is the sound is so relaxing with simple, soft music, I fall asleep! Point is it's at least breaking in.
Have fun!
Vince
I have the same problem. We won't know until the changes are made.
I'm going to give my amp a month or more before making any changes.
Been listening every night. Problem is the sound is so relaxing with simple, soft music, I fall asleep!
Point is it's at least breaking in.Have fun!
Vince
How Nicoch???
Pls pls Nicoch - do you have little schematic for the caddoc and the ldr - and how it is integrated. But this maybe belong to a B1 tread???
Now I have tried the Obbligato and the Amstrad - seems VERY promising!!
Will come back with more listening-impression in due time.
Best
Olav
Nope Alov
Pls pls Nicoch - do you have little schematic for the caddoc and the ldr - and how it is integrated. But this maybe belong to a B1 tread???
Now I have tried the Obbligato and the Amstrad - seems VERY promising!!
Will come back with more listening-impression in due time.Best
Olav
No AS-4440's available yet. Antek does have AN-4440's though. They say,
Does anyone think the lack of EMI shielding would make a difference?
Regards,
Dan
You could maybe check SumR transformers. Supposed to be good quality. I priced some once and they seemed a bit cheaper than Plitron. More expensive than Antek, but they are in Toronto, so no border hassles. I haven't used any though.
SumR - Richard Sumner Technology
Steve.
The SIT amplifier [a la Rothacher] has undergone modifications and improvements since its introduction. The first version used light bulbs as the load resistor to the SIT device. It gave this amp an intrinsic output impedance of 11-13 Ohms; that of the light bulbs which were connected between the ouput node and V+ [or AC ground]. Rothacher replaced the light bulbs with an inductor in his second generation SIT amp. The inductor increased the gain and output power of the SIT amp. The inductor simultaneously increased the intrinsic output impedance of the amp. The third generation SIT amp was the work of many interested DIYers who used a CCS [modulated and not] to attain as high or higher intrinsic output impedance as SIT V2 per Rothacher. I like SIT V2
Clearly, the above SIT amps are phase inverting transconductance amplifiers [TCAs]. I have been experimenting with mating a Voltage Source Amp [or VSA; a Threshold S/150] with a diy TCA which is not a SIT design to make a Compound Power Amplifier. The thread by the same name is in the Pass Labs Forum. THe bottom line is: One can now experience the voice of a SIT amplifier [I prefer V2 by Rothacher for its hi output Z] as a Voltage Source Amp [instead of a TCA]. Food for thought and experimentation. Your input will be valuable and appreciated.
Clearly, the above SIT amps are phase inverting transconductance amplifiers [TCAs]. I have been experimenting with mating a Voltage Source Amp [or VSA; a Threshold S/150] with a diy TCA which is not a SIT design to make a Compound Power Amplifier. The thread by the same name is in the Pass Labs Forum. THe bottom line is: One can now experience the voice of a SIT amplifier [I prefer V2 by Rothacher for its hi output Z] as a Voltage Source Amp [instead of a TCA]. Food for thought and experimentation. Your input will be valuable and appreciated.
The nature of the SIT is that it has an intrinsically low output impedance,
so the output impedance of the amplifier is that of the SIT in parallel with
the impedance of whatever is feeding it current. Typical output Z for a SIT
is like 4 ohms or so, so if you have a 20 ohm light bulb for the current source
the output impedance will be 4*20/(4+20) = 80/24 = 3.33 ohms.
so the output impedance of the amplifier is that of the SIT in parallel with
the impedance of whatever is feeding it current. Typical output Z for a SIT
is like 4 ohms or so, so if you have a 20 ohm light bulb for the current source
the output impedance will be 4*20/(4+20) = 80/24 = 3.33 ohms.
The compound approach decreases the underlined to that of S/150 which I believe is less than 0.1 Ohm. Damping factor, voltage gain, and distortion performance of the compound become those of S/150.The nature of the SIT is that it has an intrinsically low output impedance,
so the output impedance of the amplifier is that of the SIT in parallel with
the impedance of whatever is feeding it current. Typical output Z for a SIT
is like 4 ohms or so, so if you have a 20 ohm light bulb for the current source
the output impedance will be 4*20/(4+20) = 80/24 = 3.33 ohms.
Mr. Pass, the underlined is competitive with that of a 4 Ohm loudspeaker. The bolded statement says that S/150 will [may] dump [or force] some of its output current into the SIT device?. What will the impact be on the SIT device. What does it it mean? I am having a hard time understanding this. I hope that you could shed light and elaborate. Thank you.
The plate resistance of the 2SK82 is a little closer to 8 Ohms, in case you're wondering where I came up with the "around 8 Ohms" output impedance figure from the second article.
Thank you for responding. The SIT amp has a unique voice. I am describing another way [in the compound approach] to use it; for whatever value this brings.
Do you mean a complimentary pair version?
I have 2 pairs of 2SK82 and 2SJ28 that I am dying to make an amp with. Seems to me the only complication is a pair of power supplies for the bias. They would float off the rails and seems like an F6 approach would work.
Rush
Rush: I am not sure about the underlined. A rough schematic from you will help. Please note that I am not using single devices but rather stand alone power amplifiers. The Compounding approach is to operate a VSA and a TCA in parallel. The VSA is a stand alone high fidelity voltage source amplifier like any power amp out there that you make or buy; be it Class A, Class AB, Class D etc. You, others and I believe any such VSA has a unique voice in a reference loudspeaker. The current output of this VSA is summed with that of a high fideliy transconcondutance amp [TCA] which also has its other unique voice. The net contribution of the currents flowing from both sources [VSA and TCA] through the same reference loudspeaker creates a duet voice. I speculated early on that such a Compound Amplifier may "model" the operation of Conceptual F6. I actually borrowed the use of an interstage transformer in this Compound Amplifier from Conceptual F6. Please visit the Thread entitled Compound Power Amplifiers in the Pass Labs Forum for more details.
A potentially new application for SIT amplifier
I do not have a SIT Amp. Thus, I am not able to reduce to practice the title experiment. But, Mr. Pass, Mr. Rothacher, and Ms/Mr{s} DIYER who have a SIT may consider doing the experiment. It is an authentic new approach to operate a SIT. Please consult the attached file for the working schematic.
Objective: Marry a SIT amp with a voltage source amp [VSA] to make a Compound Power Amp [CPA].
Outcome: A CPA which has SIT attributes [power and character] and the objective performance of VSA.
Scope of Application. Broad and includes the mating of a variety of transconductance amps [TCAs] with a variety of VSAs.
Precedent I have assembled a CPA which is comprised of a THRESHOLD S/150 as VSA, and a DIY TCA made with bjts [opposed collector complementary pair for its output]. Works and sounds great via an A/D/S L-730 loudspeaker. The application works; but will it extend to include a SIT?
Procedure: It is like I used for my CPA prototype.
I do not have a SIT Amp. Thus, I am not able to reduce to practice the title experiment. But, Mr. Pass, Mr. Rothacher, and Ms/Mr{s} DIYER who have a SIT may consider doing the experiment. It is an authentic new approach to operate a SIT. Please consult the attached file for the working schematic.
Objective: Marry a SIT amp with a voltage source amp [VSA] to make a Compound Power Amp [CPA].
Outcome: A CPA which has SIT attributes [power and character] and the objective performance of VSA.
Scope of Application. Broad and includes the mating of a variety of transconductance amps [TCAs] with a variety of VSAs.
Precedent I have assembled a CPA which is comprised of a THRESHOLD S/150 as VSA, and a DIY TCA made with bjts [opposed collector complementary pair for its output]. Works and sounds great via an A/D/S L-730 loudspeaker. The application works; but will it extend to include a SIT?
Procedure: It is like I used for my CPA prototype.
- Open Switch to isolate VSA
- Minimize the volume of potentiometer at the input of VSA.
- Set generator at 100 Hz, and apply a low level sine signal to SIT to get a readily measurable Vo with an AC multimeter or scope.
- Sweep the frequency of the source between 20 Hz and 200 Hz. Note the two frequencies which generate the Highest and Lowest Vo. The lowest Vo is expected to be in the range of 100-200 Hz. This corresponds or mirrors the minimum impedance of the loudspeaker.
- Set the generator at the lowest frequency.
- Increase the level [Ei] to VSA with potentiometer until its output [Eo] equals the value of Vo. Measure it with the same multimeter or scope.
- Close switch A. The measured voltage at the Joint [JO] is still the same value as Vo or Eo.
- Sweep the generator frequency between 20 Hz and 200 Hz. The output voltage at JO is expected to be constant throughout, and equal in value to that of solo VSA or SIT measured earlier at the lowest frequency.
- This CPA is now tweaked.
- Open switch A, and power down VSA, and SIT.
- Change your source to a music signal, and power back up.
- Open switch A and listen to solo SIT.
- Close switch A and listen to CPA.