SSS a Hartman Manning Affair

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martin manning
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Re: SSS a Hartman Manning Affair

Post by martin manning »

From your description, the signal could be grounded out at the filter output, which is where you were working. Maybe the shielded cable is shorted? Check the resistance to ground.
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dreric
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Re: SSS a Hartman Manning Affair

Post by dreric »

martin manning wrote: Tue Jan 16, 2018 11:02 am From your description, the signal could be grounded out at the filter output, which is where you were working. Maybe the shielded cable is shorted? Check the resistance to ground.
I check in and around the filters, all good.

I did find 2 pins on V2 that I neglected to solder. Quickly fixing those I plugged in awaiting my total reward........................to find a totally dead amp. Not a peep, no hiss, no sound, nada. Voltages are all the same, just like it's not connected to the speaker.

WTF? I gotta go to bed
Eric
1949 Zenith, Zenith Toggle Recoil, Zenith 55 & 440
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martin manning
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Re: SSS a Hartman Manning Affair

Post by martin manning »

If the DC operation is stable (same voltages) then surely it’s a signal path issue. A quick and dirty test is to probe the grids with your meter, starting at the power stage, and listen for a pop in the speaker. One thing you can say is that since you had some reverb recovery signal the problem is likely to be around the point where the dry and wet signals are mixed.
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dreric
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Re: SSS a Hartman Manning Affair

Post by dreric »

So ................ I was happy to find this. The source of silence.

With the CF replaced, I still have and amp which seems to be giving me only the reverb signal.

All of the control on the front panel for with the exception of the filters. At least I know where to look.
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Eric
1949 Zenith, Zenith Toggle Recoil, Zenith 55 & 440
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dreric
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Re: SSS a Hartman Manning Affair

Post by dreric »

IT"S ALIVE!!!!!!

The beast lives!

Found a stray wire from the stranded wire input into the filters, one little fiber taking out the signal into the filters.

All issues fixed, presence work well, FET works well, filters are GREAT (go Martin!) very usable frequency shifts.

Cabinet is ready!

Happy!
Eric
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dorrisant
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Re: SSS a Hartman Manning Affair

Post by dorrisant »

Awesome!!!

Time for clips? Too soon?
Seriously, glad you got it working.
"Education is what you're left with after you have forgotten what you have learned" - Enzo
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dreric
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Re: SSS a Hartman Manning Affair

Post by dreric »

Ta Da!
IMG_1052.jpg
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Eric
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martin manning
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Re: SSS a Hartman Manning Affair

Post by martin manning »

Woo Hoo! Very nice looking cab, too, well done!

I guess that obviously bad tube was hiding on the other side of the chassis, just where you couldn't see it.

So, how is the UL sounding to you? Is the presence effective? You might want to experiment with the GNFB level (varying the FB resistor) to see if the comments above about it not playing well with UL are valid. Note that Sunn used it. You could also try shorting out the inductor in the filter circuit and see if it is doing anything ;^)
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didit
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Re: SSS a Hartman Manning Affair

Post by didit »

dreric wrote: Thu Jan 18, 2018 7:42 am Ta Da!
Big round of applause <111 seconds duration>

Best .. Ian
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dreric
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Re: SSS a Hartman Manning Affair

Post by dreric »

martin manning wrote: Thu Jan 18, 2018 8:16 am Woo Hoo! Very nice looking cab, too, well done!

I guess that obviously bad tube was hiding on the other side of the chassis, just where you couldn't see it.

So, how is the UL sounding to you? Is the presence effective? You might want to experiment with the GNFB level (varying the FB resistor) to see if the comments above about it not playing well with UL are valid. Note that Sunn used it. You could also try shorting out the inductor in the filter circuit and see if it is doing anything ;^)
The tube was funny. I Traced the loss of signal to the CF tube, probed and checked everything twice, then said "i wonder it the tube is bad?" I was very happy to see that it was.

I'll be able to run it through the paces this weekend but my immediate reaction to the UL is that I like it a lot. This is a very different amp than my #002. Crisper and more urgent. I'm sure a lot of that is the 6550s. The presence is effective, all the way up it gets a little harsh but that may have been the amp out the the cab and florescent lights in my shop. We'll see. '

Martin, I truly appreciate all the help and guidance you've provided through the course of this build. I've learned a lot and really value the wisdom you share with our community. I'm going to shoot a little video running through the controls so you can hear your filters in action.
Eric
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martin manning
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Re: SSS a Hartman Manning Affair

Post by martin manning »

You are most welcome, and I appreciate the investment of time and money you have made to try out some new ideas. I think you have a pretty solid design there now. I’d love to hear a demo clip, and I’m sure others would too. For demonstrating the filters, I liked the way the video from Carter's Vintage was done, where the player was strumming the same chord and quickly stepping through the settings on the high and low knobs. That made it easy to discern the effect, since a wide range of frequencies is present.

To tame the top end of the presence, try decreasing the value of the presence cap.
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M Fowler
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Re: SSS a Hartman Manning Affair

Post by M Fowler »

Great job building this wonderful amp and thanks Martin and all people helping out way to go guys.

Mark
Last edited by M Fowler on Thu Jan 18, 2018 6:08 pm, edited 1 time in total.
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pompeiisneaks
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Re: SSS a Hartman Manning Affair

Post by pompeiisneaks »

Very cool to see you got it working! I too would love to hear some clips!

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fred.violleau
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Re: SSS a Hartman Manning Affair

Post by fred.violleau »

Can’t wait to hear the result! Wonderful build BTW! What wattage is the output? How would you compare the sound of 6550 to 6L6s?


Humble and Dumble,

Fred.
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martin manning
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Re: SSS a Hartman Manning Affair

Post by martin manning »

I estimate a bit over 80W, and the 6550's aren't even breathing hard. They are beam tubes like 6L6's, so other than being about 50% bigger (42W vs 30W Pa max), they are not that much different. In this case, the UL power section is probably the dominant factor.
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