Finishing the Pultec!

[synthi]

Hi people,

I`m finishing my dual Pultec eq, first, here are some photos:

The channel 1 is working without problems, but the channel 2 is having an strange (for me) problem:

-first the signal is way louder than channel 1 and noise is about -65dB rms(-110rms for channel 1)
I swapped the tubes between the channels and still the same, so the tube is not the problem

-Also channel 2 hi boost and bandwith don`t work, attenuation does work and lo boost just a kind of (about the half gain as channel 1)
Then I swapped the front PCB for channels 1&2 and still the same problem, channel 1 is working and channel 2 exhibit the same problems with channel 1 front attached, so the problem must be with the main pcb. I checked the components and all sems to be ok, not bad solders, not broken pcb lines, and voltages are the same for the 2 eqs. the only I can`t test is capacitance for the condensators...

I`m using 3 transformers: a large toraid with two 12v secs each one feeding an eq, then 2 small trafos for 12:220, one for each eq. all voltages are ok. I measured voltages at several points from both channels and both shows the same voltages...
ITOH, both channels have 6V at tube heater, is this ok?

Hmm, I`m not very experienced and I`m really missing here.....
Any help is really apreciated.

Thanks!

Synthi.

 

[Steffen]

you maybe swapped pins on the filter pcb connector?

I´d connect filter pcb1 to amp pcb 2 and vice versa to check which board the troublemaker is.

great looking unit btw. :thumb: :grin:

steff

 

[synthi]

Thanks Stefen,

I did that, also checked for swapped pins and that I`ve found is that the problem comes from amp pcb 2, the amp pcb 1 works great with both filter pcb 1&2 and amp pcb 2 have the same problem with both filter pcbs...

I`ve done the frontpanel usinf FPD, modified from the NRG pultec. I have the file if anyone is interested.

synthi

 

[gyraf]

Looks very, very well!

Check, check, and double-check pcb traces, connections, components, and values...

Jakob E.

 

[synthi]

Thanks a lot Stefan and Jakob,

You were right, I had a pin swapped

Also I had a couple of cold solder points. now is working wonderful.... :green:

I was measuring the noise with the eq in and out:

eq in: -101 dB RMS
eq out: -102 dB RMS

Great!

synthi

 

[synthi]

Now a couple of pics of the pultec with her (?) new friends:

:grin:

 

[gyraf]

:shock:

Very, very nice indeed...!

Jakob E.

 

[chrissugar]

Nice collection. :thumb: :thumb: :thumb:

chrissugar

 

[radiance]

Nice Pultec & in good company...

 

[toby]

hey you gotta a valveverb too, those things are so underrated.

 

[synthi]

Thanks for the comments.
Now I`m wonder about the meq5, any news Jakob?

Toby: yes they are underrated, I got mine for about 100 euros and sound very very nice, the tremolo is vactrol based and the spring reverb very nice. I use it for my rhodes 88. I just changed the "peavey" brand tubes for TFKs and now sound wonderful.

Best Regards,

Synthi.

 

[drpat]

...

 

[matta]

Hey Synthi,

The Pultec looks great! Keep us posted. Your other gear looks
like fine company. I am thinking about getting a pair of the
Neumann W491A for myself. What do you think of them?
Nice smooth sound? Do you use them mainly for mastering,
or tweaking/processing individual tracks. Prob going to pair
them up in a rack with a pair of ANT pre's I have.

Cheers

Matt

 

[dukasound]

Hi Synthi
Look my post about my Pultec.
Thanks
Duka

 

[synthi]

Thanks drpat,

yes, the controls are reversed up/down but since I never used a true pultec is not a problem here

Matt: I like very much the W491As, I`m using them mainly for tracking and individual tracks when mixing but also for mastering when I need additional bands. They sound great even in bypass... :razz:

Duka: I replied you in your own post.


Synthi.