Drip Dual-STA 5167 Limiter

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JMan

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Oct 26, 2019
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312
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Chicago
Sc said:
The reason why some SMA cables are very expensive is the RF use (transmitting) with rated cables. According to Drip you don't need these and you may use the cheep ones. Personally I think SMA is a good thing for must be shielded signal applications - but why use it for uncritical connections ? Like the IDC's better there. And maybe it's nonsense, but I don't use it for high power (heater) and high voltage connections unless I know the rating of the cables - that's the expensive ones.

Makes sense.  I will have to go double check which connections are which (diy has slowed down for me since the holidays), but I suppose the main thing I’ll look out for are the high power/voltage connections, and invest a little more money into appropriately rated cables there, and use the cheapo cables for the other ones.  It does seem reasonable to at least know the rating of the cables in those important spots, even if it turns out (for example) that all SMA cables clear the necessary ratings by default.
 

FarisElek

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Oct 26, 2019
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407
Just a random update. My Dual Sta is running strong. I've ran 24 hours straight before and it gets hot but nothing too crazy. I had to strap a 1k resistor across pin 2 and 3 of my meter pot to 0 the meter for some reason.

I wouldn't use NOS 6v6 tubes if trying to get both units running in stereo together. Used matched NOS tubes I paid way too much for and they sounded amazing but the discrepancy between outputs was too much to bare any longer. Using matched JJ's I got a long time ago and the unit runs perfectly in stereo. Sounds fine. New production 6V6 recommendations welcome.

Love it on vocals. Just tracked vocals for a friends album blasting the unit and it just makes everything sound upfront and beautiful. I like it better than my LA2A when ran at similar attack and release (#2 is about the same-ish). Would love to make a HPF for the Dual Sta though as it will considerably suck bass out of a whole mix at faster time settings.

Overall recommend the build as long as you know what you're doing already....
 

JP Audet

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Mar 6, 2018
Messages
8
I know it’s an old thread but I’m currently picking up parts for this bad boy. Thank you all for sharing such useful info.

For a Simpson 27 meter in the US:

https://www.metersales.com/shop/product/42714-28796#attr=47190,81496,71732,59310,92196

Have build two Drip Opto 7 few years ago and gotta say the Opto documents are very straightforward in comparison.

I’ll definitely post here if I get stuck at some point.

Cheers!

Jp


 

FarisElek

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Oct 26, 2019
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407
Definitely let me know if anything comes up. There is some new documents for this build that I've only glanced at. I worked so hard to get mine as close to original spec as possible voltage wise. Had to do some cooky stuff.
 

JP Audet

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Joined
Mar 6, 2018
Messages
8
Hi guys!

I went for Jensen jt-10k61-1m output transformers.

I’m not quite sure how to hook them up to the main board.

It also came with a 22uf @ 250v cap. Once again, I don't really know what it is for...

Specs :

https://www.jensen-transformers.com/wp-content/uploads/2014/08/jt-10k61-1m.pdf

https://www.jensen-transformers.com/wp-content/uploads/2014/08/as021.pdf

Would be very appreciated if someone could help.

Thx a lot!!!

Jp






 

FarisElek

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Oct 26, 2019
Messages
407
JP Audet said:
Hi guys!

I went for Jensen jt-10k61-1m output transformers.

I’m not quite sure how to hook them up to the main board.

It also came with a 22uf @ 250v cap. Once again, I don't really know what it is for...

Specs :

https://www.jensen-transformers.com/wp-content/uploads/2014/08/jt-10k61-1m.pdf

https://www.jensen-transformers.com/wp-content/uploads/2014/08/as021.pdf

Would be very appreciated if someone could help.

Thx a lot!!!

Jp


I may be wrong, I didn't look too hard. But they don't appear to be push-pull output transformers. Regular single-ended output transfotmers aren't designed to receive high DC. The push-pull you're supposed to use receive extremely high DC. You'll likely destroy those transformers. Sowter, Hammond, and Edcor make suitable transformers for this build and I'm not aware of any others, although I haven't looked hard.
 

juneaudio

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Mar 8, 2019
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Ive read through this thread carefully and I haven't seen anything yet - has anyone put together a digikey or mouser cart for the BOM?
 

JMan

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Oct 26, 2019
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I don't know if someone else will be able to share a cart or not (I don't have one), but I would think that it shouldn't be too hard to put together, just tedious. It's laid out pretty clearly in the build manual.
 

juneaudio

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Mar 8, 2019
Messages
3
still having a hard time putting together the right components for this build and haven't had any luck getting Drip to update their site with a new digikey cart, etc. anyone available to help? im even willing to just send some $ over for a copy of your parts list or invoice from digikey, etc
 

FarisElek

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Oct 26, 2019
Messages
407
Just take the manual and go down the line of the parts and go to mouser on another tab and get what you need. I used WIMA caps and Dale/Vishay resistors because that's what I like to use. This is probably the easiest part of this entire build to be honest.
 

Martan

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Nov 9, 2019
Messages
37
I just put a txt file with the numbers from my digikey invoice in that dropbox folder, but I don't have a cart link. Haven't built it yet so take the cart as a best guess. It's also not all you need. For instance I don't think digikey carried some of the pots.
 

morls

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Jul 15, 2013
Messages
163
Location
Australia
Great thread!

I've just finished my build, it's up and running but there is an issue with the left channel. The output is clipping big time, even when the output is turned down all the way. When turned right down the low end of whatever track is playing still clips my converters, and the signal is very distorted. I'm only getting distorted low end. When bypassed the signal is good, but the meter still shows gain reduction. I've swapped tubes between the channels, and it's not a tube issue. Main board voltages are very close, although the 105VDC test point near the input transformer is measuring around 114V, and much higher when compressing. This is the case on both channels.

The second channel is much better, although I think it's still running hot as I can hear a lot of distortion at 15dB compression and higher. The meter on this channel doesn't show gain reduction when bypassed.

I'm still working out the wiring for the meters and LEDs. This might be the cause of some distortion, but I'm not sure yet. I need to play around a bit more and try to find the right way to wire this, it doesn't want to work if I connect all the meter and lamp points from main board to control boards.

A lot of trial and error at the moment, but I'm happy to have it up and running. Any tips on the distorted channel would be very welcome. Its interesting that the distorted signal is still present with the output attenuator turned right down...

Stephen
 

morls

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Jul 15, 2013
Messages
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Sorry to hijack this thread, I should have thought about it...

As far as working out the BOM, I photocopied the manual and went through the parts list line by line, used a highlighter to mark each component as I added to the Mouser cart. Some parts I had to go to Digikey, I think the Grayhill switches and some of the thermal kits. It's tedious, but at least you get to know the build, and you can see what options there are for the resistor types etc
 

morls

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Jul 15, 2013
Messages
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Location
Australia
Definitely let me know if anything comes up. There is some new documents for this build that I've only glanced at. I worked so hard to get mine as close to original spec as possible voltage wise. Had to do some cooky stuff
I've read through this thread but I'm stuck with my build now, and was wondering how important getting all the voltages to original spec is? I have one channel working, but the other is not. I get some signal, but as soon as I push the input there is some serious clicking going on, peaking. There is also audio leaking into ground, I can get a signal from the chassis when I turn up the input. Only in this channel.

Another clue is that the secondary low (blue on the Sowter) isn't passing signal. This is on the output side of the transformer, so I thought maybe the attenuator was playing up. But the issue remains even though I swapped around control boards.

Following your lead, I went through and re-soldered all the joints. I've swapped output transformers, tubes, control boards, input cables. I'm going to go through and get all the voltages from the test points in the original schematic, and see where they sit. The main board test points for 300V are spot on, so I'll dig a bit deeper.

This leakage to ground is driving me mad! At the moment I'm going through the feedback circuit.

Here are some pics, I'm using dual-6BA6s instead of the 6386. Everything else is as close as I could get to the Drip documentation.

This thread gives me hope that I can sort out the issues, well done on getting yours up and running, and thanks for posting so much info
Cheers
Stephen
 

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Sc

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Feb 3, 2020
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Switzerland
Hey - cute build ! Sorry I didn't read all the early messages/threads - the fairly strange issue you describe is hard to track down from far. Did you check the SMA connectors and cables (short/continuity)? The cheaper ones are crap sometimes. As to the voltages - usually the tensions may be in a range of +- 5 - 10%. I tend to 5% beeing perfect. Measure the Sowter DCR between high and low (one lead disconnected). Good luck ...
 

FarisElek

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Oct 26, 2019
Messages
407
Yeah I'd take one side of every sma cable off and check from the pin to ground. Anywhere where a ground is close to a high voltage point. Also, there is going to be continuity between ground and high voltage when the device is switched off. This has to do with tubes basically being diodes. Also some meters say anything under 100 ohms is continuity but If there is 100 ohms in the way, that's technically not continuity. Also, If your high voltage was actually hitting ground you'd blow a fuse immediately. I think your problem is something else and you're just getting hung up. Same thing happened to me actually.
 

FarisElek

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Oct 26, 2019
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407
Voltages should be within 20%. You're able to set all the voltages with the blue little trimmers all over the PCB, so be specific which voltages you are talking about.
 

Clakejr

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Joined
Oct 31, 2019
Messages
16
I've read through this thread but I'm stuck with my build now, and was wondering how important getting all the voltages to original spec is? I have one channel working, but the other is not. I get some signal, but as soon as I push the input there is some serious clicking going on, peaking. There is also audio leaking into ground, I can get a signal from the chassis when I turn up the input. Only in this channel.

Another clue is that the secondary low (blue on the Sowter) isn't passing signal. This is on the output side of the transformer, so I thought maybe the attenuator was playing up. But the issue remains even though I swapped around control boards.

Following your lead, I went through and re-soldered all the joints. I've swapped output transformers, tubes, control boards, input cables. I'm going to go through and get all the voltages from the test points in the original schematic, and see where they sit. The main board test points for 300V are spot on, so I'll dig a bit deeper.

This leakage to ground is driving me mad! At the moment I'm going through the feedback circuit.

Here are some pics, I'm using dual-6BA6s instead of the 6386. Everything else is as close as I could get to the Drip documentation.

This thread gives me hope that I can sort out the issues, well done on getting yours up and running, and thanks for posting so much info
Cheers
Stephen
What kind of hookup wire are you using?
 
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