Kleinulator on VHT D-Fifty - Gain problem

[Da Sting]

Hi everyone; I have a Kleinulator in the loop of a VHT D-Fifty for some time now, dialled in correctly (by the book of Klein) and working. Until I had the amp in a situation where I had to turn up the master volume beyond 11:00. The Kleinulator started misbehaving, starting with signal compression going over to farty, rectangular distortion. What was dialled in as unity gain at rehearsal volume was way less signal compared to direct signal (Kleinulator taken out) when turning up the master to big stage volume. Took the effect loop side out, tried to dial in differently, no change. As I took the Kleinulator out of the send/return at the amp for good, I also noticed that the box takes away a noticeable chunk of the amp's liveliness. Maybe I did not a/b the rig properly when I set it up. Stupid me.

Putting my analog Ibanez Chorus, analog EHX Phaser and a (digital) Strymon Reverb on top of the amp with patch cables in the amp send/return does NOT distort at higher levels and sounds neutral.

Do I maybe have a defective unit?
Is there another transparent sounding buffer amp solution for the amp (preferably small, mountable in the amp shell)?
Can I use a simple Pedal Buffer amp at the amp's send output (anybody knows the max. level for these)?

Thanks & Cheers, Frank

[erwin_ve]

Hi Frank, Did you turn up the master of the amp or did you turn up the master of the Kleinulator?

Possibly you overload the first stage of the Kleinulator. Best is to keep the master on your amp where it doesn't overload the Kleinulator.

The signal chain in.the amp is:
preamp-master volume-fxloop-power amp.
I don't know what voltages are on the FET in the Kleinulator, but normally you would turn up the last pot on the Kleinulator to maintain the level what normally would come out of the preamp I other words, the last pot on the Kleinulator is your new master volume when it's in the fx loop.
To counter the loss of highs((through impedance) between the amp and the kleinulator you can experiment with the bright switches on the Kleinulator.
Hope this helps.

Erwin

[Da Sting]

Thanks, Erwin; it did help - the Master comes before the loop output, I kind of forgot that. I turned that up and probably drove the KU into distortion. *sigh* I'll try again and report later - I'll have a look into the treble loss as well.
What is kind of inconvenient: The functional Master Volume is now down at the back of my amp somewhere...
Cheers, Frank

[Da Sting]

@erwin_ve: Spent some time yesterday fiddling around, still: The sound starts to compress / distort badly when I turn the master volume up past 11:30 (what would be the input gain to the KU and the loudness range I want to perform with) no matter what I dial in with the send (even close to nothing), the return or the recovery (that would be the master volume then). Tried everything, if I take the KU out, the sound is clear and beautiful on Master Volume at noon with some slight breakup.
Past a certain point, the KU behaves nasty, distorts badly and limits the overall gain it can put out, never reaching the gain level that goes in.

Feels like a defective unit to me...

[1] I have not opened the KU yet; were there some older models without the built-in 9 to 36v converter in the silver case? Are these voltage pumps prone to breakage?
[2] And - what alternatives are on the market?
[3] Is it possible to rewire the VHT D-Fifty loop to pre Master Volume to work with a more consistent gain range?

The amp as is sounds brilliant. I just need a reliable effect loop not colouring or changing the signal that works even when it gets louder than rehearsal volume. Anybody got a good idea?

Thanks & Cheers, Frank

[erwin_ve]

@erwin_ve: Spent some time yesterday fiddling around, still: The sound starts to compress / distort badly when I turn the master volume up past 11:30 (what would be the input gain to the KU and the loudness range I want to perform with) no matter what I dial in with the send (even close to nothing), the return or the recovery (that would be the master volume then). Tried everything, if I take the KU out, the sound is clear and beautiful on Master Volume at noon with some slight breakup.
Past a certain point, the KU behaves nasty, distorts badly and limits the overall gain it can put out, never reaching the gain level that goes in.

Feels like a defective unit to me...

[1] I have not opened the KU yet; were there some older models without the built-in 9 to 36v converter in the silver case? Are these voltage pumps prone to breakage?
[2] And - what alternatives are on the market?
[3] Is it possible to rewire the VHT D-Fifty loop to pre Master Volume to work with a more consistent gain range?

The amp as is sounds brilliant. I just need a reliable effect loop not colouring or changing the signal that works even when it gets louder than rehearsal volume. Anybody got a good idea?

Thanks & Cheers, Frank

I'm not sure why you want the master on the amp up. The chance is it is overloadibg the first fet stage on the Kleinulator. You mentioned a slight break up when volume is at noon with nothing in fx loop. Keep the master volume on 1/4 and let the Kleinulator do its job. Then ask yourself: Is it the recovery on the Kleinulator that cause this behavior or the master volume on your amp?
On the Kleinulator: I'm not familiar what is inside in detail besides 2 fet gain stages like a Dumblelator.
What I do know is the Fuchs verbrator, is a tube based fx loop, that does sound really well in ODS type amps. Amd you got reverb as well with that unit.

[Da Sting]

My bad - this came over irritating, I guess: I did not properly mention that whatever value the Master is, I can't have the gain all back with only using "Recovery" Stage on the KU... the amplification at that stage is not enough even when setting the KU "Send" only slightly before max level, "Return" at max level.
My thinking is that there should be at least enough gain available at the "Recovery" stage to have at least unity gain (same as w/o KU in amp) when you set "Send" back slightly to 2:00 - 3:00 to get down to pedal levels; in this case I need even more gain for stage volume levels (as the "Recovery" stage is the PI driver now).
Confusing.

Klein-Ulator inside:

ceriatone-klein-ulator_inside_small.jpg

Cheers, Frank

[erwin_ve]

My bad - this came over irritating, I guess: I did not properly mention that whatever value the Master is, I can't have the gain all back with only using "Recovery" Stage on the KU... the amplification at that stage is not enough even when setting the KU "Send" only slightly before max level, "Return" at max level.
My thinking is that there should be at least enough gain available at the "Recovery" stage to have at least unity gain (same as w/o KU in amp) when you set "Send" back slightly to 2:00 - 3:00 to get down to pedal levels; in this case I need even more gain for stage volume levels (as the "Recovery" stage is the PI driver now).
Confusing.

Klein-Ulator inside:ceriatone-klein-ulator_inside_small.jpg

Cheers, Frank

Not irritating, just unclear, in what exactly you have tried. Fe in your response you mentioned "I can't have the gain all back with only using "Recovery" Stage " This is confusing, Gain of what exactly?
My point was; if you put the master on your amp 1/4 (like 9 or 10o clock) then set the send on the Klein maxed, the return on the Klein maxed and the recovery on the Klein to taste what happens?