Z Wreck

[DR.Z]

[quote="M Fowler"]Bypass caps read 25uf/25v to my eyes and that is the value I used to build my Zwreck.[/quote]


That's correct Mark.
250mF 50V on bias resistor bypass.


Z

[M Fowler]

That's correct Mark.
250mF 50V on bias resistor bypass.

Thanks Mike, and I must say you got a winner with that Zwreck really like the videos showing how versitle the Zwreck can be.

It seems that the B+5 is feed off the B+3 node rather than B+4 step down keeping the voltage high on the V1 tube. At least that is where I wired mine.

Also did you experiment with running a switch for the 220k/220k voltage divider incase a guy wanted to cut that in and out?

Mark

[M Fowler]

TheGimp

I knew the pins were wired differently from a 12AX7 but good to know about the increased noise with the 6N2P tubes.

I got a PCB from a TAG member, nice guy, and his amp uses three of those 6N2P tubes so I will be getting those and trying them out, never used them before, should be interesting.

Mark

[Richie]

the ones used in amps i have had here, have been fine,and no noise,in higher gain circuts. Some are different rated. 12ax7 tubes can be the same way though. some hum,hiss,or microphonics more than the next one.

the last letters indicate the type.. like EV, EB K etc..
http://www.tubedata.info/tubnum.html


After symbol dash and postfix of one or more letters may be added:
B high reliability tube (military)
E long life tube (military)
H designed for impulse operation
K vibration resistant

[argonaut]

Bypass caps read 25uf/25v to my eyes and that is the value I used to build my Zwreck.

That's correct Mark.
250mF 50V on bias resistor bypass.


Z

Thanks for the confirmation, Z. Excellent sounding amp.

[argonaut]

That's correct Mark.
250mF 50V on bias resistor bypass.

Thanks Mike, and I must say you got a winner with that Zwreck really like the videos showing how versitle the Zwreck can be.

It seems that the B+5 is feed off the B+3 node rather than B+4 step down keeping the voltage high on the V1 tube. At least that is where I wired mine.

Also did you experiment with running a switch for the 220k/220k voltage divider incase a guy wanted to cut that in and out?

Mark

Hey Mark,

I put that divider on a push/pull pot on my last build and it works great. It really helps with some of the hotter humbuckers to drop some signal t ground.

[M Fowler]

Richie I had noticed the EV, EB K ratings and was thinking about EV as the choice.

argonaut, I had some TAG guys telling me to do the switching as an option some like it and some don't, hit and miss thing.

Mark

[M Fowler]

Removed and posted to new thread.

[TheGimp]

As it looks to me like this subject is going to continue, I started a new thread on Russian / Soviet tubes so as not to hijack this thread:

http://ampgarage.com/forum/viewtopic.ph ... 898#144898

Lets please continue there.

Thanks.

Steven

[crafty1]

[quote="M Fowler"]Maybe it is the choke I used, Hammond 158L 15hy, but my wreck build stays very clean to about 3 pm on the volume knob. I might try a different choke to see how that interacts.

Have it switched from 260 to 300v HT Heyboer 5199 and 4k3 Heyboer
which is not M6 steel so all the differences in components I used are probably adding up. Did not use all MF resistors either.

I ordered the correct Russian EL84's and will see how those work out. Running GT 12AX7 gold series right now for preamp and PI.

Mark[/quote]


Mark,

I would say that the 260 - 300 volt PT would be the correct one for the Z wreck. The fact that this amp is using 7189 tubes which handle higher plate voltages would support this as most cathode biased ( AC30 type amps ) using EL 84's generally use PT's in the 275 - 285v region - GZ34 rectified.

Also, looking at a gut shot of the Z wreck the Voltage divider resistors and PI bias resistors ( going by the color coding ) look a lot like 120K and not 220k. Could just be the picture quality playing tricks - maybe not?
Z has used 120k values to bias in other builds, SRZ 65 + Prescription Jr and possibly in the Mazerati GT.

Note also the long tail input resistors are 976K - not the traditional 1M and the 47.5K ( not 47K ) resistor to Earth in this section.

Crafty

[DustyBadlands]

Ordered some parts for my version of the this amp today. Should be fun!

Anyone care to post their version?

Silver tolex on the Z-Wreck. My favorite!

[M Fowler]

Finishing up on the amp waiting on the head cabinet and 212 cabinet in Navy instead of silver.

We noticed the 976k and 47k5 resistors as well but think that the voltage divider is 220k but your correct my eyes couldn't tell the values but my friend was better then me at this but still no assurance the values are correct I agree.

But were not cloning just going by known Rocket values and voltage divider circuits done before.

[M Fowler]

The amp has more bass then usual so without knowing what the real Zwreck uses I will have to adjust accordingly by ear.

Any effect on tone when using the 220k/220k voltage divider?

I used a Hammond 158L choke and that could be a problem area as well, but the cap is only 47uf B+ so that should not be a root cause for the darker tone.

Mark

[tweedeluxe]

Looks like a 47p (41p?) bright cap on the volume pot, which might suggest that the pot is 1M instead of 500K - assuming this is mostly a tweaked Rocket. If so, the ceramic cap off V1 might be ~250p instead of 500p.

Looks like a 100k in the cathode follower circuit too - less CF compression than the rocket.

Is that a 1k resistor in the PSU feeding the PI?

[M Fowler]

Looks like a 47p (41p?) bright cap on the volume pot

I used a 100pf silver mica like the Rocket.

which might suggest that the pot is 1M instead of 500K - assuming this is mostly a tweaked Rocket.

I wondered the same thing but used the 500k like the Rocket.

If so, the ceramic cap off V1 might be ~250p instead of 500p.

Used a 510pf polystryene cap here.

Looks like a 100k in the cathode follower circuit too - less CF compression than the rocket.

Yes

Is that a 1k resistor in the PSU feeding the PI?

Guessing 1k2 there?