I would like to respectfully request that posts like this be kept to the Conspiracy to Commit Electronics megathread as it is not directly related to a Sushi Box pedal.Received my Tayda order for a nobelium. The electrolytic capacitors are mostly JB JFB series. I don't have an opinion on those but I've seen them in electronics. Don't remember if I had to replace any due to swelling.
The one non JB brand is a Chongx for C1. Those are the worst caps I've seen. Replaced many swelled one over the years, particularly in the power supply section. And guess what? C1 is in the power section. I prefer a name brand that is low impedance for C1.
Top brands are Rubycon, Kemet, Panasonic, WIMA, and Nichicon. I think I've listed them in correct order by market share. I will use Rubycon simply because that's what I have on hand. For the film capacitors, I have a mix of Kemet and WIMA. I'll probably use a mix of those two.
The resistors came in quantities of 10 and are cut tape. I did test 1.5k ones and found all 10 are within the 1% tolerance rating.
The Noble guy uses Nichicon electrolytic and mostly WIMA film capacitors. I don't have enough gut shots to tell what the few non-WIMA film capacitors are. He also mostly uses carbon film capacitors, not the metal film ones in the Nobelium BOM. I see one metal film in the gut shot. I'm guessing that the equivalent to the 10M R17 in the Nobelium.
This makes sense because carbon film is usually preferred over metal film for tube amp builders. Probably because carbon comp resistors are what's found in sought after Vintage amps. I have both types but probably will use carbon film except for the 10M part.
In the sticky section, there is a demo of various preamps including Noble and Nobelium. I can hear a difference between the two on the low end. The Noble sounds slightly better to my ears. Perhaps this is why guys on the pedalpcb forums are talking about changing the HPF on the Nobelium. I think they were talking about lowering it slightly. Iirc, from 90hz to 70hz or so. The member there that said he designed the Nobelium (can't confirm that and this is the Internet) at the same HPF value as the Noble. No mention of the slope though.
All three have the same pinout as the 12A*7 family so they should theoretically be drop-in replacements. 12DW7 is a dual triode with one high gain (mu of 100) and one low gain (mu of 20) triode, like 1/2 12AX7 and 1/2 12AU7. I haven't personally used them, but I've seen them used in preamps. 12BH7 has a mu of 17 which is even lower than 12AU7, but it has a high plate current so I've actually used it as a low-wattage power tube in my headphone amps. ECC99 is similar to 12BH7 with a mu of 22 and a high plate current, but I've never personally used them.hey Nathan,
12dw7, 12bh7(a) and ECC99 -- have you tried these? can they theoretically be used for any pedals, or not?
seems like they're just variants of any other common 12ax,t,y,v,u7/ECC81,2,3,x tube out there.
I use NOS ECC802S tubes in many things, as well as 6189W, and sonically they're great, and rugged.
@Sushi Box FX
Based on Radial's documentation, the JDI has an input impedance of 140kΩ, so I wouldn't expect that to be an issue with Underground Accelerator's output impedance of 38kΩ. That being said Underground Accelerator does not has a buffered output as it takes the output straight from the gainstage. Typically a buffer is characterized by a high input impedance (≥1MΩ) and a low output impedance (≤1kΩ)., and Underground Accelerator does not qualify on the output side.Hey guys
I just wanted to ask a simple question that might not have such a simple answer? I have my new UA hooked up to my board with a couple of pedals in front and a JDI after. I have come to the realize that the output volume is quite dependant on what I hook the JDI up to. I know that it is passive - but I was kind of hoping that the output of the UA would act as a buffer and help drive the signal?
As it turns out putting a buffer between the UA and the JDI makes quite a bit of difference. I just wanted the hear about other people's experiences and recommendations in this regard? I'm a little worried that I will have to keep some sort of buffer between them reducing my options on the board (I run a smallish Nano+ board).