My Rocket voltages

[Mark]

In order to find out if my Rocket clone is running as it should I measured all the voltages per the chart created.

Some of the voltages are a departure from what is listed.

I am concerned at how hot this amp is running. I find in hard to touch the amp any longer than 20 seconds. The tubes are all running at and above their specification which is a worry, especially in a wooden cab. I wonder if the flash point of the finish has to be considered?

I'm thinking of using a zener to lower the voltage 290 or 300. Though Allyn stated:

Voltages are dead on for the Rocket I copied. B+ is very low (like the originals) around 270VDC-275VDC.

http://ampgarage.com/forum/viewtopic.php?t=5866&start=0

I have used a zener to get the amp to 265VDC and it loses a lot of treble and vibe.

Allyn also makes this point:

100V +/- 5 on V1 (like the original.

My amp has about 81VDC on V1 with the higher rail.

All thoughts welcome.

[Richie]

what value cathode resistor are you using on the EL84s

Whats up with the voltage on the grids?

[Mark]

Thanks so much for having a look at my voltages Richie. I'm using the standard 50 ohm resistor. The 15 and 18 mV on the grids have been with me during the whole build. I did try and increase the cathode resistor value to get rid of it, but it was all to no avail.

http://ampgarage.com/forum/viewtopic.ph ... id+voltage

Here is another set of voltages for general reference.

http://ampgarage.com/forum/viewtopic.ph ... et&start=0

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Links regarding this amp.

http://ampgarage.com/forum/viewtopic.ph ... ge&start=0

http://ampgarage.com/forum/viewtopic.ph ... id+voltage

http://ampgarage.com/forum/viewtopic.ph ... id+voltage

http://ampgarage.com/forum/viewtopic.ph ... id+voltage

http://ampgarage.com/forum/viewtopic.ph ... id+voltage

http://ampgarage.com/forum/viewtopic.ph ... id+voltage

http://ampgarage.com/forum/viewtopic.ph ... id+voltage

These links are to assist other doing a search for articles and questions on the Rocket. It purely a self help thing.

[RJ Guitars]

Mark,

Sorry to be slow to look this thread over, I really got busy for a while there but this is a good topic with lots to be discovered and contributed along the way.

I'm not sure where that original Heyboer HTS-9144 PT came from but it must have been based on one of the earlier Rockets. It seems to match up with most of what is declared as genuine for a Rocket. I did get a look inside a later Rocket and it used the Liverpool taps on a Pacific transformer. Same dropping string so I figure this had to run just a bit hotter than the previously mentioned standard.

There are great sounding samples from amps using voltages anywhere from 250 to 280 VAC on the secondaries so it's hard to say if anybody is wrong... only thing that seems important is to change the bias resistor on the output tubes if you run the higher voltages.

I'll take some time now and go through all those links you posted. Thanks for starting this thread! Every time we open this dissussion up we discover a few more pieces of the history and learn a bit more about getting the best out of a Rocket.

[Mark]

Look forward to your observations R.J.