Parallel loop - for ampgarage users only :-D

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Andyjoe
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Re: Parallel loop - for ampgarage users only :-D

Post by Andyjoe » Sat May 15, 2010 4:14 pm

I put this in my 50 watt and I am having trouble with it overdriving the whole amp clean or overdrive. Anyone have this problem.

Andy

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Structo
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Re: Parallel loop - for ampgarage users only :-D

Post by Structo » Sat May 15, 2010 4:38 pm

If you turn the Send pot up too much you will overdrive the effects and if you have the return pot too high you will overdrive the phase inverter.
Cut the send and return back.

Did you install the bypass switch?

If so try to make the loop and bypass the same volume.

I like mine with the output pot (instead of the 220k fixed), that way I can turn up the gain and master on the amp and use the loop output pot for overall master.
Tom

Don't let that smoke out!

soje
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Re: Parallel loop - for ampgarage users only :-D

Post by soje » Wed Nov 17, 2010 10:11 pm

I'm planning a built of the dumbleator, and would like to use the parallel/series version Bluesfendermanblues posted (thanks!)


However there's a bit I don't understand: what's the purpose of the 220k resistor from output the the "0" node?


Regards.

soje

bluesfendermanblues
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Re: Parallel loop - for ampgarage users only :-D

Post by bluesfendermanblues » Wed Nov 17, 2010 10:37 pm

soje wrote:I'm planning a built of the dumbleator, and would like to use the parallel/series version Bluesfendermanblues posted (thanks!)

However there's a bit I don't understand: what's the purpose of the 220k resistor from output the the "0" node?
Regards.

soje
If you what background in, try this link: http://aikenamps.com/FeedbackAmp.htm

All I did was to combine the Dumbleator with Aiken's and Kevin O'Conner 's ideas and I did a little trial and error testing to find suitable component values.

So far, I have implemented the loop in three amps - 50w HRM, EL34/ 100w Non HRM, 6L6/ 100w Bluesmaster, EL34 - and I find that it works well in both serial and parallel mode. However, if you want to 'crank' it up in serial mode, you've got to replace the output 220k resistor with a pot.

Personally, I only use the parallel mode. I don't have a TC2290, but an old, cheap SE70, which is nothing special, but it sounds great in parallel mode, since the direct signal is obviously not interupted in the amp/ signal chain.
Diva or not? - Respect for Mr. D's work....)

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Structo
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Re: Parallel loop - for ampgarage users only :-D

Post by Structo » Wed Nov 17, 2010 10:41 pm

Funny, I was just revisiting this idea the other day.
I may convert my serial loop into the series/ parallel one that I did a layout for.

I will probably have to make a new eyelet board but I'm thinking I would like to try the parallel loop again.
Tom

Don't let that smoke out!

soje
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Re: Parallel loop - for ampgarage users only :-D

Post by soje » Wed Nov 17, 2010 11:34 pm

bluesfendermanblues:

Thanks for your answer!

I'm (somewhat) familiare with Aiken's site. What threw me off, is that there's already the 10M - .22uF - 10M network. Are you simply adding another fb-network, and what does it do soundwise?

Another thought: since most pedals and effects have some sort of output volume control, isn't the "mix-pot" sort of redundant?

I hope it's ok to ask!


I need the loop for my newly acuired G-major (got it cheap off the net - 1300 DKK). I've been fiddleing with something of a kleinulator, and the effect should definately be in parallel :-) Makes one appreciate what the amp you built can do tone wise :-)



Regards
soje

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Structo
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Re: Parallel loop - for ampgarage users only :-D

Post by Structo » Sun Nov 28, 2010 1:58 am

No the mix pot mixes the wet / dry signal.
Most effects you will set full wet, then adjust the mix.
Tom

Don't let that smoke out!

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angelodp
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back

Post by angelodp » Sun Nov 28, 2010 5:40 am

Tom, please do keep us posted on your series/parallel project. Would love to convert my extra Dlator to this mode.

Best Ange

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hans-jörg
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Re: Parallel loop - for ampgarage users only :-D

Post by hans-jörg » Thu Dec 02, 2010 12:55 pm

Hallo,
I will start soon with a D´Clone build and would appreciate to start it with a build in D`lator. How far is your projekt, Tom?
I´m rearly glad to be a member of this forum too.
Thanks
Hans-Jörg

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Structo
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Re: Parallel loop - for ampgarage users only :-D

Post by Structo » Thu Dec 02, 2010 2:18 pm

The amp is done, I haven't built the parallel dumbleator yet.
I have the series dumbleator that works well.

That is why I haven't jumped on the parallel bandwagon yet.
Tom

Don't let that smoke out!

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angelodp
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1.3k

Post by angelodp » Fri Apr 08, 2011 6:33 pm

Just wondering about this 1k3 resistor .... I also see 1k5 and the cap that goes along.

I see .22uf , .47uf and 4.7uf on various layouts

Which values are correct for R&C please.

Ange

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Structo
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Re: Parallel loop - for ampgarage users only :-D

Post by Structo » Fri Apr 08, 2011 9:13 pm

Ange I'm sure a 1K5 cathode resistor would work fine.
I think I have a 1K2 on mine, probably because I couldn't find a 1K3.

The reason to use the larger bypass cap is to ensure a full frequency response is guaranteed.
Not sure you would hear any difference between a 25uF and a 47uF.

There is a .47uf on the cathode follower, but that is a coupling cap to keep the DC off of the Drive or Send pot.

More critical to the sound is that the cathode follower first stage has 30-32v on the cathode.
Adjust the 27K tail to get that voltage right.
Tom

Don't let that smoke out!

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angelodp
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Great article

Post by angelodp » Fri Apr 08, 2011 9:45 pm

Thanks Tom, that cleared things up.

A

mshowson
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D'lator built in

Post by mshowson » Tue Aug 02, 2011 2:17 am

I built the "original" serial d'lator into my 100 watt ods using the clause circuit found in the files.
It works well and seems transparent as far as tone and gain are concerned but when switched in, I have a low level hum. Not awful but annoying none the less. Tried all shielded wiring with no change. Tried all non shielded wire, no change. Moved the return side plate B+ to a different node (further down the rail) No change. Clearances and proximity to other components looks ok.
Might this be an un-fixable artifact of the buffered loop? Or maybe someone else has been down this road and can offer some direction.
Thanks, Mark H.

bluesfendermanblues
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Re: D'lator built in

Post by bluesfendermanblues » Tue Aug 02, 2011 9:50 am

mshowson wrote:I built the "original" serial d'lator into my 100 watt ods using the clause circuit found in the files.
It works well and seems transparent as far as tone and gain are concerned but when switched in, I have a low level hum. Not awful but annoying none the less. Tried all shielded wiring with no change. Tried all non shielded wire, no change. Moved the return side plate B+ to a different node (further down the rail) No change. Clearances and proximity to other components looks ok.
Might this be an un-fixable artifact of the buffered loop? Or maybe someone else has been down this road and can offer some direction.
Thanks, Mark H.
I assume that you have build the loop into your amp - since you have "Moved the return side plate B+ to a different node (further down the rail)"

My experience is that a build-in loop should have ONE ground only - eg. to one of the chassis bolts of the loop 12ax7 tube. AND you need to add a seperate node to the PSU as well. This new node should be grounded to the above mentioned ground connection, on the loop tube chassis.
Diva or not? - Respect for Mr. D's work....)

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