Lets talk about pot values for the SP-9

Hi everyone, my name is Tommy. I'm new around here, but have been trolling for a couple weeks now. I have recently decided to get back to my 'roots', so to speak, and build a hi-fi system. After a bit of research and some recommendations, I came across tubes4hifi. Roy was beyond helpful and super accommodating with my order. I ordered an SP-9 (I'm afraid to give up tone control, baby steps, I'll build more), a PH-14 phono preamp, and a pair of mk3's. My order came in two shipments and Roy mistakenly sent me two parts kits for the SP-9. The parts kits were identical other than the fact I received a 100ka in one and a 250ka volume pot in the other. Before I send one of these bags back, I was wondering which would best suit my application. Most of the information I was able to gather points to using the 100k, but I wanted to be sure. I would like to use the 250k just for the fact that the PCB has extra ground pads that fit the shielded wire I plan to use perfectly. My main source is going to be the PH-14, and will be my only source for the time being.

Thanks in advance for any help you can offer. I'll have quite a few more questions along the course of this build I am sure. I hope you will forgive my lack of Hi-Fi knowledge, we've all got to start somewhere. I can, however, solder pretty darn well, and I've built quite a few devices, almost all pertaining to guitar. I'm looking forward to this project and future projects in hi-fi audio.

Here is a 100w 2 channel optically switched high gain guitar amp I built based on the schematic of the Soldano SLO 100.





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Tommy,
Nice workmanship....What output tubes are you using with your guitar amp....6L6's ?

By the way...Welcome to our Forum.

Kevin

Thanks! Yeah, I am using JJ 6l6 tubes in that amp.

I opted to go with 100k volume pot for the SP-9 build. I ordered a 'make before break' rotary switch and the resistors to build a ladder attenuator.

My next question is about the balance control. I have enough parts to build a stepped attenuator for this as well. A balance pot is completely new to me since I pretty much deal only in mono devices. Am I correct in assuming that the balance pot is two 'W' taper pots wired inversely?

spin wrote:Hi everyone, my name is Tommy. I'm new around here, but have been trolling for a couple weeks now. I have recently decided to get back to my 'roots', so to speak, and build a hi-fi system. After a bit of research and some recommendations, I came across tubes4hifi. Roy was beyond helpful and super accommodating with my order. I ordered an SP-9 (I'm afraid to give up tone control, baby steps, I'll build more), a PH-14 phono preamp, and a pair of mk3's. My order came in two shipments and Roy mistakenly sent me two parts kits for the SP-9. The parts kits were identical other than the fact I received a 100ka in one and a 250ka volume pot in the other. Before I send one of these bags back, I was wondering which would best suit my application. Most of the information I was able to gather points to using the 100k, but I wanted to be sure. I would like to use the 250k just for the fact that the PCB has extra ground pads that fit the shielded wire I plan to use perfectly. My main source is going to be the PH-14, and will be my only source for the time being.

Thanks in advance for any help you can offer. I'll have quite a few more questions along the course of this build I am sure. I hope you will forgive my lack of Hi-Fi knowledge, we've all got to start somewhere. I can, however, solder pretty darn well, and I've built quite a few devices, almost all pertaining to guitar. I'm looking forward to this project and future projects in hi-fi audio.

Here is a 100w 2 channel optically switched high gain guitar amp I built based on the schematic of the Soldano SLO 100.





Facebook of my small DIY pedal company

WOW!...that is AMAZINGLY clean and neat wiring!!! WELL DONE!!!!!!

spin wrote:Thanks! Yeah, I am using JJ 6l6 tubes in that amp.

I opted to go with 100k volume pot for the SP-9 build. I ordered a 'make before break' rotary switch and the resistors to build a ladder attenuator.

My next question is about the balance control. I have enough parts to build a stepped attenuator for this as well. A balance pot is completely new to me since I pretty much deal only in mono devices. Am I correct in assuming that the balance pot is two 'W' taper pots wired inversely?

Fantastic work on the guitar amp! The ALPS balance control normally used in the SP9 has a MN taper. http://www.alps.com/prod/info/E/PDF/Potentiometer/TAPER.PDF

So at center detent, both channels are at max. And it looks like linear taper to ground with a little knee. That's how I first pictured it in my mind. I did find this image when looking into it the other day:



This is where I got the idea of two 'W' pots wired inverse to each other. At center detent it is passing 90% of each channel. My logic thinks that the 100% at center would be the better way to go. But something is telling me that the 'W' taper configuration would 'feel' better. Has anyone explored this before?