Forums - 2 Z-Kit’s one images one does not ?

Dixieusa

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Posts: 26

2 Z-Kit’s one images one does not ?
12/27/25 at 06:23:41

I have built two z-kit’s one is SS rectified the other is Tube rectified. The circuits are identical other than rectification and the anniversary mods. The SS rectified amp images beautifully the speakers disappear while the tube rectified amp does not image at all. Any thoughts would be welcomed.

SS voltages A -341 B-300 C-10.49 D-2.6/2.6

5U4 voltages A-313 B-278 C-9.6 D-2.4/2.5

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MM Seasoned Member Posts: 397	Re: 2 Z-Kit’s one images one does not ? Reply #1 - 12/27/25 at 16:06:28 I don’t think it’s the rectification. I have built both and preferred the diode for its speed and resolution. Both imaged very well. Check the hazen mod and make sure everything is correct there, then maybe take a look at parts quality. I assume you have swapped the tubes to rule that out?
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Dixieusa Verified Member Posts: 26	Re: 2 Z-Kit’s one images one does not ? Reply #2 - 12/27/25 at 19:03:40 Update Changed rectification to solid state = no change in imaging Changed hazen caps to Mundorf 0.1 = no change in imaging Changed coupling caps to Mundorf 0.1 = no change in imaging Question would the long leads for tubes from pcb to sockets have any affect. The amp is dead quiet with no hum
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MM

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Posts: 397

Re: 2 Z-Kit’s one images one does not ?
Reply #3 - 12/27/25 at 20:35:26

Why the jumpers at J4, J5, and J6?

I don’t believe it would be the leads to the tube sockets causing your issue. I have built this circuit every which way imaginable and never experienced what you are experiencing with the imaging, which tells me there is a part out or place or out of spec.

Maybe one of the more experienced folks can chime in. Keep us posted. Solving these things is fun, despite your inherent frustration.

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Cambridge CXN100, SRA Signature Hybrid Mamushi IC, SEWE 300b, ZSTYX SC, Lii F15 & W15 in open baffle.

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Dixieusa Verified Member Posts: 26	Re: 2 Z-Kit’s one images one does not ? Reply #4 - 12/27/25 at 22:24:45 Question Could the transformers be responsible The tube rectified amp is using the original ZKIT output transformers Edcore EM4030 & which ever power transformer was supplied in the kit The SS amp uses the newer Edcore WXPR107 and GXSE10-8K transformers
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Dixieusa Verified Member Posts: 26	Re: 2 Z-Kit’s one images one does not ? Reply #5 - 12/28/25 at 04:09:39 I have checked all the capacitors and resistors everything is in spec. Tried 3 different rectifier tubes another pair of SV83’s and a pair of EL84’s I’m Baffled For what it’s worth the amp sounds wonderful just doesn’t image
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Dixieusa Verified Member Posts: 26	Re: 2 Z-Kit’s one images one does not ? Reply #6 - 12/28/25 at 04:36:51 Also swapped out the preamp tubes both 6N1P & 6922
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MM

Seasoned Member

Posts: 397

Re: 2 Z-Kit’s one images one does not ?
Reply #7 - 12/28/25 at 05:01:55

Why only two connections where the volume control attaches? Does it return to the board somewhere else?

When you say not imaging, do you mean it’s in mono? That would indicate a connection shorting out between channels.

I don’t think it’s your transformers.

Again, cut out the jumpers J4-J6. You can skip a large part of the board by making those external connections to your RCA’s by inserting the wires further up the circuit and crosses a lot of points on the board off the list. Connect your RCA’s to the volume pot then the pot to the input tube directly. You can use a continuity meter to check for bleed between channels.

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Cambridge CXN100, SRA Signature Hybrid Mamushi IC, SEWE 300b, ZSTYX SC, Lii F15 & W15 in open baffle.

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Dixieusa

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Posts: 26

Re: 2 Z-Kit’s one images one does not ?
Reply #8 - 12/28/25 at 05:17:16

Jumpers 4,5,6 have been removed, they were not doing anything as the end of the board with the inputs and outputs had been removed in order for the board to fit inside the chassis. Outputs are wired directly to the transformer and volume pot is wired directly to the inputs.
When I use the term imaging I am talking about the instruments sound as they are coming from a specific place vocals are usually centered the speakers will literally disappear, if you were to look at a speaker you would swear that it was not playing. Speaker placement plays a key role and room acoustics definitely help, I have all that covered.attached photo shows my listening room

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MM Seasoned Member Posts: 397	Re: 2 Z-Kit’s one images one does not ? Reply #9 - 12/28/25 at 05:51:42 Interesting. So with one zkit the speakers disappear and to you get the phantom stereo image and with the other you don’t. It’s definitely not the transformers. Not sure.
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Dixieusa Verified Member Posts: 26	Re: 2 Z-Kit’s one images one does not ? Reply #10 - 12/28/25 at 06:04:03 Indeed quite odd
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MM Seasoned Member Posts: 397	Re: 2 Z-Kit’s one images one does not ? Reply #11 - 12/28/25 at 23:05:05 Nice looking room. Maybe I missed this, but if you run the two zkits as monos do you notice the one not imaging?
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Dixieusa Verified Member Posts: 26	Re: 2 Z-Kit’s one images one does not ? Reply #12 - 12/29/25 at 01:04:58 I don’t know but I will give it a try
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Dixieusa Verified Member Posts: 26	Re: 2 Z-Kit’s one images one does not ? Reply #13 - 12/29/25 at 01:58:25 You may be on to something, the tube rectified amp will not bridge in either series or parallel. The SS amp bridges properly
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Dixieusa

Verified Member

Posts: 26

Re: 2 Z-Kit’s one images one does not ?
Reply #14 - 12/30/25 at 06:28:47

Problem solved last night I tried bridging the amp and had no output. This morning I put the amp back into stereo mode and again no output.rechecking my work I found that the first 33uf cap read as leaky , replaced both 33uf caps and behold not only did the amp work but now it was imaging. Long story short, I built the amp with parts that I had on hand, I did not have any new 33uf caps and put in used ones. Thank you to everyone who helped me figure out what the problem was.

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Lon Seasoned Member "Love without guts is worthless!" Philip K. Dick Posts: 27185	Re: 2 Z-Kit’s one images one does not ? Reply #15 - 12/30/25 at 13:11:39 Fantasti!c! Glad that this has been solved.
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MM Seasoned Member Posts: 397	Re: 2 Z-Kit’s one images one does not ? Reply #16 - 12/30/25 at 13:53:33 Diddo. Glad you got it working. If it’s not a bad solder joint it’s usually one of those caps.
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