- Darkvoice 336Se Vs Bottlehead Crack mod#
- Darkvoice 336Se Vs Bottlehead Crack driver#
- Darkvoice 336Se Vs Bottlehead Crack mods#
- Darkvoice 336Se Vs Bottlehead Crack series#
I use Z foils transforms the sound completely. the 250K pot - the Alps Blue isn't a good volume control but a the 'shunt mod' changes this, highly rec.
Darkvoice 336Se Vs Bottlehead Crack mods#
Mods - your cathode idea is good - what value of LED did you use, was it HLMP 6000, is this value critical? If I can improve on the overall sound of the D/V then I want to keep the pre-amp part of the circuit. The single channel diagram you posted has 2 resistor values at variance with the amp I have - 6SN7 pin (1) yours 100K, mine reads and measures 1M brown/black/black/yellow, same tolerance 1% : your pre-amp resistor 2K, mine reads and measures 1M brown/black/green, same tolerance 5%. I'm wondering how much of the dynamism of this amp is to do with the 250K pot? only a small amount of movement possible past 9, not surprising. Surprisingly from new and using the supplied Chinese tubes the sound was very good and straightaway I could hear the attraction of OTL amps. Of course the first thing I did was remove the base plate and take a look - nicely put together. Even better because it was sent 'in transit' to Germany before being sent on to France I did'nt have to pay any VTA or Customs inspection fee.
Darkvoice 336Se Vs Bottlehead Crack driver#
I decided to get a D/V 336 SE via Massdrop because I had never tried an OTL or any kind of equipment built using point-to-point and it used a very versatile driver tube type of which I have many, it was also a good price. I've been reading various reviews from this site for some time but seeing this thread prompted me to join. There are other mods too, but most of those are replacing components (Alps pot, MKP caps, etc.). Still not sure if taking this 220 would change the bias or operating point of the 6SN7. There is already a 30K resistor in line there that will do just fine. This will only increase the plate voltage and increase the headroom.
Darkvoice 336Se Vs Bottlehead Crack series#
Drop the 220 ohm resistor in series with the plate of the 6SN7. There are better configurations, but I would almost rather take it out the LED all together.ģ. There is a safer way to incorporate an LED on a heater rail, but this is a bad implementation. Take out the LED on the heater rail and replace with a lamp. This would work and would actually likely knock it down closer to 6.3V, but might cause some extra strain on the transformer as the specs on the transformer are unknown and may not have suitable amps for this section of the transformer.Ģ. One person fixed it by converting the AC heater rails to DC. Some 6SN7's are more sensive to high heather voltages and why different tubes as well as "burning in" or leaving it on can cause the hum to go away. It seems this is the biggest cause of the hum in the preamp tubes. Not as big a change as lifting the Line Out, but much improved. It retained much more detail and clarity and less sag.
This change made it even closer to the Crack.
This allows for a much more steady biasing voltage. I simply removed the 1K cathode biasing resistors on the 6SN7's and replaced with LED's just like the Crack.
Darkvoice 336Se Vs Bottlehead Crack mod#
This is a fairly simple mod and also one I borrowed from the Crack schematic. The Crack might have been slightly better given better components and design overall (better transformer, correct heater voltage, and less resistance on headphone out, even if it did have an electrolytic cap on the output). After removing the Line Out loading issue, they were close to the same given the same tubes.
I compared it to a Crack initially and the DV was much darker. This change simply lifted the "veil" on this amp. So for mine I disconnected the Line Out all togehter, but one could simply remove the connector to ground essentially taking that part of the circuit out of the equation. But somehow the extra capacitance and resistance to ground on the DV moves up the HPF to 1.2Hz, but also somehow contributies to somehow loading the output. You will see there is no line out, but it has a similar headphone output with a decoupling cap of 100uf in series and a 2.49K resistor to ground.įor the DV circut, the high pass cutoff frequency would be about 0.53 Hz.įor the Crack circuit, the HPF cutoff frequency would be about 0.64 Hz.īoth use the same design, but the Crack uses a higher value cap and a lower value resistor, but achieves the same result. The 0.47uf series cap and the 2K resistor to ground cause some type of loading to the output. I will start this thread to discuss different mods to this or any similar designed OTL cathode follower amp. I know there is much to discuss about Crack mods, as many of them they sell directly. Let me be the first to start this thread.
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