Xits X10 = liverpool half power?

[angelodp]

Thanks Soma_Hero - Corrected.

Work in progress.

[dorrisant]

I didnt play with that circuit for long, found it frustrating, AND i had ordered one by that time which ive since abandoned.

Are we to understand that you cancelled your order for an X10? ... Just curious as to where we will look to confirm values.

EDIT: Nevermind... and thanks for the PM responses guys.
Tony

[chopstuck]

I just reread the whole thread. I built the amp back in 2011 and was never happy with it other that it was tidy. I went back and forth between the generations. Now have the 12AU7 in position V2 and the divider. THe full larmar 250k 2M2 PPI MV and I think I will next try juggling the voltage divider. I'm not giving up yet. I have the choke in but disconnected. The voltages under static load varied by abut 4-7 vdc on the nodes and plates. Not sure about the under heavy load.

[chopstuck]

Success , finally. Sounds like the 10 year old video. The 12AU7 and the 220k off the treble pot wiper was key... and the 82K grid leak got it tamed down.
I lost the 470k/470k divider and reconnected the choke.
Another on in the bag.
I was the second post on this antique thread.
Now I'm done.
Gonna learn some of those Fat licks from Greg...

[mush]

Hi,
I know this thread is very old. The links for the photo's no longer work. Xits seems to be long gone with the demise of FatSound. There's no way to buy a new Xits X10 amp and the very few used specimens cost a fortune. Searching this thread, it appears that the circuit here is an approximation. I might give building one a go if I can get a good version of the circuit. Does anyone have an accurate schematic of the X10?
Thank you and happy new year.

[rooster]

There's one a Carter Vintage guitars, Nashville. $1500 and very clean.

[mush]

Thank you, Rooster.
I wish I could afford it.
I have most of the parts, except the power transformer to make one, so that's a more desirable route.
Here's what I've figured out from the notes in the previous pages.
Any comments and criticisms will be greatly appreciated.
Thank you all - m

[Colossal]

Mush, that schematic is still valid. Rectified voltage should be on the order of an 18W type amp. About 340-350VDC.

[ChopSauce]

Yes, that looks good. Thanks for the update.

[mush]

Regarding the power transformer, this thread originally had 300-0-300 and 1k AC dropping resistor per secondary leg. I've seen similar setups using lower secondary voltage and a mere 100 ohms for dropping resistors. 1k seems like a lot of heat will be generated in the chassis and it's a bit of a concern.

Has anyone confirmed what Xits used for secondary AC and dropping resistors?
What was the favored spec for the power transformer and the AC secondary dropping resistors?

[Colossal]

Actually, yes....that very likely should be 100Ω 10W, not 1k. I would have to re-read the whole thread to jar my memory on this whole forensic exercise. My bet is the PT was a Mercury 18W-type 300-0-300. They also make one in that line that is 316-0-316VAC. The 300VAC will load to 345VDC rectified, so I would guess they were using the 316-0-316 and padding the secondaries down with 100Ω. Why? No clue.

EDIT: I just looked in my notes and confirmed and yes, those are 100Ω for sure, not 1k.

[mush]

I'm guessing it's the 300-0-300 transformer. I just modeled it on PSUD using 250 ohms as series resistance on the vac secondary and 100ma load. I got about 335vdc for the B+1.

I've attached a schematic with the transformer specs.

I'm thinking of using a lower secondary voltage, maybe 275. A B+ of 355 is beyond the 300vdc limit of specified on the EL84 data sheets I have looked at. Am I being to conservative on this?

The two 100 ohm resistors simulate the kind of rectifier tube sage one would find using something like a 5Y3. I'm thinking this was the idea.

My last annoying question: Does anyone have the Xits X50 schematic? I just heard one on the YouTube and it's magnificent.

[mush]

I forgot to ask what speakers are preferred with the X10?

[Colossal]

I'm guessing it's the 300-0-300 transformer. I just modeled it on PSUD using 250 ohms as series resistance on the vac secondary and 100ma load. I got about 335vdc for the B+1.

I've attached a schematic with the transformer specs.

I'm thinking of using a lower secondary voltage, maybe 275. A B+ of 355 is beyond the 300vdc limit of specified on the EL84 data sheets I have looked at. Am I being to conservative on this?

The two 100 ohm resistors simulate the kind of rectifier tube sage one would find using something like a 5Y3. I'm thinking this was the idea.

My last annoying question: Does anyone have the Xits X50 schematic? I just heard one on the YouTube and it's magnificent.

Most amps operate EL84s outside of their published RCA specs, some to peril, others to fortune and glory. There is also a tonal consideration to the change in operating point. You would certainly experiment with a lower plate voltage, while trying to keep the preamp and PI at the XITS voltages.

I have no information on the X50, sorry.

[joeboo88]

Hi Colossal and everyone else who contributed to this thread
I just want to say thanks for all your work on getting a working schematic done
This is one example of what makes this site great.
Joe