Greeting,
I recently had my +10db gain tube pre develop issues with it's muting relay. Which caused a channel imbalance so I'm in the process of swapping the relay. This caused me to insert my 0db gain passive temporarily. Which has caused quite a welcome ruckus on the analog end. As before I was experiencing pretty substantial subsonics that would end up effecting the tonearm producing compounding issues at higher volumes.
To make a long story short awhile back I had run all of the math on the adjustments on my hybrid phono pre. And found that with one setting, with this cartridge, that I could boost the phono output by around 6%. So the usual occured with the other sources, and especially with the CD player, the passive preamp lacks the last couple of volume clicks. Which has always been the case. But with the phono input it is just a giant step forward here. As the gain is sufficient and the noise and subsonics have for the most part vanished.
So I've determined that I'm going to add a set of passive outputs to my +10db tube preamp. And perhaps even a toggle that will mechanically select between active or passive.
This means that I'll have to source a appropriate shielded twisted input wire to add between the volume control and the switch and output jacks. And that has me pondering what type and guage to use. I'd like to perhaps introduce a tad more spice so I'm thinking silver or silver plate in a smaller guage. I've noticed the designers in this case have switched to copper from the past silver plate. At least in the active designs and they dropped the passive model from the lineup. So any thoughts on the best wire to use to introduce a little sparkle along with a tad more meat on the bones?
Many thanks,
DD
I recently had my +10db gain tube pre develop issues with it's muting relay. Which caused a channel imbalance so I'm in the process of swapping the relay. This caused me to insert my 0db gain passive temporarily. Which has caused quite a welcome ruckus on the analog end. As before I was experiencing pretty substantial subsonics that would end up effecting the tonearm producing compounding issues at higher volumes.
To make a long story short awhile back I had run all of the math on the adjustments on my hybrid phono pre. And found that with one setting, with this cartridge, that I could boost the phono output by around 6%. So the usual occured with the other sources, and especially with the CD player, the passive preamp lacks the last couple of volume clicks. Which has always been the case. But with the phono input it is just a giant step forward here. As the gain is sufficient and the noise and subsonics have for the most part vanished.
So I've determined that I'm going to add a set of passive outputs to my +10db tube preamp. And perhaps even a toggle that will mechanically select between active or passive.
This means that I'll have to source a appropriate shielded twisted input wire to add between the volume control and the switch and output jacks. And that has me pondering what type and guage to use. I'd like to perhaps introduce a tad more spice so I'm thinking silver or silver plate in a smaller guage. I've noticed the designers in this case have switched to copper from the past silver plate. At least in the active designs and they dropped the passive model from the lineup. So any thoughts on the best wire to use to introduce a little sparkle along with a tad more meat on the bones?
Many thanks,
DD
For line level interconnects:
a] There is almost no current, so the central conductors can be very small.
b] Above 100 Megahertz, Silver plated central conductors are great. At audio frequencies there is no advantage.
c] Chose a cable with a braided shield.
d] Chose a cable that is easy to strip, attach and solder.
a] There is almost no current, so the central conductors can be very small.
b] Above 100 Megahertz, Silver plated central conductors are great. At audio frequencies there is no advantage.
c] Chose a cable with a braided shield.
d] Chose a cable that is easy to strip, attach and solder.
If the wire type is affecting the sound, there's something wrong with the equipment...or expectation bias is at work.
Mike
Mike
Passive preamps need a low resistance volume control, while tube preamps need a high resistance volume control.
It will be difficult to accommodate both.
It will be difficult to accommodate both.
Hi Rayma,
That's a ligit point and I have both models by the same company. The passive was the original and the +10db was apparently based around adding a active board and extra xformer to the same exact chassis. I'll have to check to see if the motorized volume pots are different impedance. I do know that that +10db is 100k. The passive is buried under a stack at the moment. But I will check that out asap.
I do find that wire for whatever reason does present slight differences. This naturally depends on the actual circuit application. But even the insulation type has an effect. And many times the cheapest plastic produces better results than teflon, ect. Plus vintage cloth inserts another not normally tested quality. I constantly use different interconnects to provide slight offsets in tonal qualities to either side. A hott sounding unit can be massaged toward greater usefulness and vice versa. In the case of passives your truly limited to wire, layout, and such as nothing else exist to be twerked..
Nevertheless, this equipment breakdown situation has eliminated a major issue in play here with analog subsonics. I run a stout bottom end consisting of 10 10" alnico vintage woofs. So there is real energy in the room. It's just astounding to find that even the simplest low gain stage can produce such negative artifacts. This has been such a ear opening event that I'm going to study slightly increasing the output of all of the other sources. I may be able to completely eliminate this gain stage all together. Which is a giant leap forward.
Happy listening,
DD
Thanks,
DD
That's a ligit point and I have both models by the same company. The passive was the original and the +10db was apparently based around adding a active board and extra xformer to the same exact chassis. I'll have to check to see if the motorized volume pots are different impedance. I do know that that +10db is 100k. The passive is buried under a stack at the moment. But I will check that out asap.
I do find that wire for whatever reason does present slight differences. This naturally depends on the actual circuit application. But even the insulation type has an effect. And many times the cheapest plastic produces better results than teflon, ect. Plus vintage cloth inserts another not normally tested quality. I constantly use different interconnects to provide slight offsets in tonal qualities to either side. A hott sounding unit can be massaged toward greater usefulness and vice versa. In the case of passives your truly limited to wire, layout, and such as nothing else exist to be twerked..
Nevertheless, this equipment breakdown situation has eliminated a major issue in play here with analog subsonics. I run a stout bottom end consisting of 10 10" alnico vintage woofs. So there is real energy in the room. It's just astounding to find that even the simplest low gain stage can produce such negative artifacts. This has been such a ear opening event that I'm going to study slightly increasing the output of all of the other sources. I may be able to completely eliminate this gain stage all together. Which is a giant leap forward.
Happy listening,
DD
Thanks,
DD
As for proper impedance matching your certainly correct. What's actually needed is a dual volume control with both sections on a common shaft. Sounds fairly easy to accommodate. The trick is to minimize the switching required to get both producing clean output. For the last couple of hours I've been petting a cira 1965 milspec titanium locking toggle switch. Which I've had stashed for decades, it may or may not look completely lost mounted in the front preamp panel. It does have that bombs away look to it but there's one way to find out. I guarantee that you will never accidentally switch it ever. It passed testing with flying colors with sub 1ohm resistance and exact equivalence on both half's. So it is a definite player.
DD
DD