[BUILD] The Rude Tube IVORY ====== Official build & support thread

[tsv]

Hi Bernd

Great thanks for the info. That's a nice read on the tone stack and it makes sense now. I have the circuit working as expected now!

Here's what that article says about the bass control:

"If the audible bass were a hump on a graph, turning the control up would move the left wall of the hump further left as the cutoff frequency descended, deeper toward the very boot soles of sound, letting increasingly low frequencies through. Turning it down would shift the left wall of the hump to the right, narrowing the hump, the range of bass that gets through."

I get this response with Bass Switch PCB Pin 3 connected to Audio PCB 1. 2 connected to 2 and Pin 3 (Audio PCB) and Pin 1 (Switch PCB) unconnected.

I plan to build a 2U stereo unit so hopefully my wiring will be ok. Pins 1 and 3 on the Switch and Audio PCB's are definitely opposite though.

BTW with the 200V Antek transformer I'm getting 247VDC on the B+.

I'm going to order the Edcor transformers next and play around with adding a bias control to the second tube stage to see what that sounds like.

Thanks!

 

[bernbrue]

Hi,
I have to check the pin orientation again, since I used simple potentiometers.  In a 2U enclose you will have enough space for the wires. Go ahead!
Bernd

 

[bernbrue]

Pay attention with that 100K resistor: High voltage and HEAT!!! 
Bernd

 

[tsv]

Thanks for pointing that out. The 3W 100k's I got are really big. I think I'll move it to the backside of the pcb.

 

[tsv]

So I played around with a bias pot today in place of R15. I had a 2.5K lying around that I could use. Pretty cool! . I think I'll add it to the panel layout since there is space. Probably use a 2K Pot.

I ordered 4 Edcor XSM10K/10K as they were in stock. I also ordered a 2U from Collective Cases. I'll work on adapting the .fpd files you provided to the collective case.

Now I need to build up the second channel!

Thanks

 

[tsv]

O and I got the Tone Stack Calculator to run on my Mac with Crossover since I don't have a PC. Very cool!

Thanks

 

[bernbrue]

1st post updated 

 

[tsv]

Hi Bernd

I'm getting back to the RTI. I have the Edcor XSM10K-10K transformers. From the look of your diagram it seems that the output transformer is wired in reverse so the output of the circuit would connect to the secondary. Is that correct?

Thanks!

 

[tsv]

Thinking about it if both sides of the transformer are 10K does it matter which way they are wired? My guess would be it doesn't

Let me know. Thanks!

 

[tsv]

Well I have got the transformers working ok but there is quite a bit of loss with them in. At least 12dB (-6dB per transformer) which I would expect. The circuit doesn't have enough gain to compensate for this though.

Bernd did you experience this? Is there a way to change the gain stage to compensate?

Thanks!

 

[bernbrue]

Hi,
I´m in France for holidays at the moment and can´t answer in detail. The loss in gain is normal, because of the gain differences in balanced and unbalanced connection. Unfortunately there is no easy solution to achieve more gain.
Bernd

 

[tsv]

Hey Bernd

Thanks for getting back to me on your vacation. Have a great time!

I'll skip the transformers then. The circuit doesn't work well with that much loss and no way to make it up.

Quick question when you get a chance. I'm going to switch over to a 6N2P form the12AX7. Does pin 9 need to be grounded?

Thanks!

 

[bernbrue]

Hi,
for the 6N2PEV just remove the link between F+ and F- and connect heater to F+ and F-, that´s it. You could use the output transformer only. Then you´ve got a nice Tube DI box. Try to get the 6N2P EV, it´s the long life version of this tube. Personally I prefer the russian tube over a standard 12AX7. For my taste it sounds better.
Bernd

 

[tsv]

Hi Bernd

Cool! Yeah I found some 6N2P-ER's on ebay from Russia. I'll try this out today.

Thanks!

 

[Winetree]

Try to get the 6N2P EV, it´s the long life version of this tube.

Ebay titles state 6N2P EV but when you look at the tube boxes they're 6N2P EB's
Is there a difference between EV and EB?
Have the P.S.Bs been sent out?

 

[tsv]

I picked these ones up

http://www.ebay.com/itm/171346100517?_trksid=p2059210.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT

The EV's are long life >5,000 hours and the ER's are rated to >10,000

Interesting the EV's are written as EB and the ER's are EP in the Russian documents. It looks like a language thing.

 

[kambo]

Hi,
be aware that you need 9VAC in order to get rectified and regulated 6,3VDC heater supply. If you really want to use this transformer, you should take the 6,3VAC directly from the transformer to the tube without stuffing the heater rail on the psu board.

So, either 6,3V alternate current directly to tube or 9V alternate current to psu to get 6,3V direct current.

If you want to go that route I would take the model with higher B+ like this one:

http://www.antekinc.com/as-05t240-50va-240v-transformer/

regards
Bernd

those antekinc transformers has 2x6.3 VAC... which makes 12.6VAC ... 
should be fine for the heaters !!!

 

[bernbrue]

Hi,
Assuming you want to built a two channel version I would provide each Tube with 6,3VAC directly from the transformer. For a mono version just take one heater supply.  So you don't need to stuff the heater part of the PSU.
Bernd

 

[kambo]

great sound

 

[bernbrue]

Yeah, nice little soundtool  8)
Bernd