EQN build thread

[edanderson]

100nf (or 0.1uf as it is more often written here in the states) is at the "large" end of the range for ceramic caps, and will generally be expensive in c0g.  you could definitely substitute a 0.1uf film capacitor in 5mm lead spacing.  panasonic ECQ-V series stacked polyester is a "jellybean" part - i keep a bag of 100 in my desk.  part P4725-ND, about 10 cents each.  wima, AVX, epcos all make box style caps in 5mm pitch that would also work.

ed

 

[zayance]

Thanks a lot for the tip, yes i have those ECQ series, in a lot of different values actually, thanks for sharing.

 

[dmp]

Looks like that 0.1uf cap is just for decoupling the V+ of the two small amp boards, so it certainly does not need to be high end.
Peter, I got my kits - they look great. Thanks much for putting this together!

 

[dmp]

Any idea when the Ed Anderson input transformer will be ready?

 

[dandeurloo]

R17 2k7/6k8 -again how do I determine the correct value?
Different schematics have different values. This is the q setting resistor for the mid inductor. I used 6k8.

Hey Peter if I use something in the middle like 5.1k will that be a wider q or sharper q then 6.8k?

 

[peter purpose]

Sharperer.

 

[Echo North]

Any idea when the Ed Anderson input transformer will be ready?

4-6 weeks would be my guess.  There are always a lot of slow downs and hold ups in the first batch.  It's all necessary to get it right!

Outputs should be back in stock in a week.

If you have any follow-up Q's please use my WM thread.

Thank guys!

Mike

 

[dandeurloo]

I'm getting close on the EQ's!  I have a few noobish questions I thought I would check in on with you guys before I solder these last few pieces in. 

1. what cap are you guys using for C50?  I have the AML kit and the WIMA cap that came with it is to wide to fit in between TR1 & TR2.  I can get the leads to reach but it doesn't sit well and it is touching everything around it.  Is there and skinny cap that can fit in there? 

2. I also am not sure what value u1K63 wima caps are?  Is that the cap for C31? 

3. I know it was briefly discussed, but how do we mount the input TX?  Do we take out two of the screws that are holding the TX together and put longer ones in and screw those through the PCB into the TX?  Or is there an different method.

4.  On the PCB next to the input TX, where it say OUT +- and in between the IN+- and the SCR there are lines.  Are we suppose to jumper those and connect the input TX to oneside of those?

Thanks for the help.

 

[peter purpose]

1. Stick it on the underside.
2. Hunh?
3. Yes.
4. No... they're extra holes for Ed's tx.

 

[dmp]

u1K63 wima caps

0.1uf C17, C18, C31

cap are you guys using for C50?

You also could order a 2.5mm thick cap, like 505-MKP24700/630/5 (mouser)

 

[dandeurloo]

dmp and Peter thanks.  This helps me sort out a few things.  I was starting to think I had some caps in the wrong spot but I think I got them right.  I'm getting much closer.

I think I will mount these 4n7 film on the underside and see how that works. 

I'm gonna have to decide on Knobs soon.  Maybe the KILO's or if Jeff has knobs coming through soon I will be set.

 

[funkymonksf]

Can someone explain what CW W CCW means for the smaller potentiometer wiring? I am assuming it means clockwise w? counter clock wise, but how do I know what is what on the PRV6?  Can anyone explain in detail. Sorry this may be the dimmest of questions yet, but here it is.... and thanks

-Brice Conrad

P.s.
Peter the kit looks great! So very excited

 

[kazper]

Can someone explain what CW W CCW means for the smaller potentiometer wiring? I am assuming it means clockwise w? counter clock wise, but how do I know what is what on the PRV6?

W= wiper and you have Counter Clockwise and Clockwise correct. Basically Peter is trying to help you not make a wiring mistake.
RV1,RV2,RV3 you should be concerned with the others are just trim pots

 

[dmp]

I think that would mean with the pot turned fully cw, the cw tab is the one with zero resistance to wiper
You can use a ohm meter to figure out which one the wiper is.
As long as you get the wiper right, worst case the knob will work backwards and then you'd have to flip the cw and ccw wires
More detail:  http://en.wikipedia.org/wiki/Potentiometer

 

[dandeurloo]

isn't the wiper always in the middle? so thats easy to find.

 

[dmp]

R17 2k7/6k8 -again how do I determine the correct value?

From the schematics it looks like the 1073 used 2.7k for R17, and 1084 used 6.8k.
If I understand it correctly, the Hi-Q switch is putting R19 in parallel with the R17.
If you want both the 1073 and 1084 options, use 6.8k for R17, then choose R19 such that you get R19||6.8k=2.7k when you flip the Hi-Q switch.
That value would be 4.5k for R19.

 

[briomusic]

thanks dmp, for xplainin how this q thang works! 

 

[loopermc5]

Thanks for this project Peter......Got mine up and running post some pics once I get knobage. So is the bias setup the same as the pre's ?

Thanks

P.s I got alpha pc mount 1/4 shaft to fit great just used a file to angle the solder pcb's some,if your looking to save some bucks. I can post pics if anyone wants to see.

 

[peter purpose]

So is the bias setup the same as the pre's ?

Exactly

 

[dandeurloo]

RV4/5 -what is the alignment procedure for these trimmers? is it similar to the 'symmectrical clipping' process on the 1290 preamp?
Exactly.

Ok, i looked at the 1290 thread.  I still am a little un clear on how to do this. 

1. Do we need to adjust just RV5 or both RV4 and RV5?

2. I don't have a scope but maybe able to go to a friend who has one.  Do I want it to hard clip or just clip?  Not sure what to look for.

3. Is there anyway to do this without a scope? 

Thanks