Rocket Reverb

[andrew]

Sorry, I dug a little deeper in the junk pile and found a 25k Audio.

[eddie25]

Out of curiosity, could it be bad for these reverb circuits to run without a tank hooked up?

[M Fowler]

No its OK to run with the reverb tank not plugged in.

[M Fowler]

Andrew I have been gone sorry. 25kL pot and 33k/2w or 3w resistor or whatever you have available to try.

[M Fowler]

Call me crazy but the best sounding speaker so far has been an Eminence Lady Luck 12" 16 ohm 70w rating.

What other speaker has the same or similiar characteristics?

Here is some info I pulled off the internet google search. The speaker is a 16 ohm model and is rated for 70 watts RMS. Each speaker sports a custom Epiphone/Eminence finish in Mustard Yellow along with the Lady Luck label on the back. The speaker has a stamped steel frame, a front , a rear sealing gasket, a 34 oz magnet, 1.75" voice coil, a full paper cone with paper edge, and a cloth dust cap. This speaker has a sensitivity of 99dB and a useable frequency range from 80Hz-5kHz. It has a very smooth response from the low-end through the mid range. It also has a very nice top end sparkle. The speaker was engineered to exhibit very warm, and smooth break-up modes. The tonality of the amp is such that very little tonal coloration from the speaker was desired. Consequently, the speaker was engineered to provide a subtle, yet effective compliment to the amplifier

Mark

[RJ Guitars]

Out of curiosity, could it be bad for these reverb circuits to run without a tank hooked up?

Eddie,
when I build my "Rocket Booster" circuit, I essentially bypass the reverb driver and tank and run the signal that goes into the reverb driver direct to the recovery stage. This gives you an added gain stage that is kinda cool in a Rocket.
So in some round about way I am saying that you can run this without the tank and maybe do something kinda cool with the boost circuit until you get your tank. You could even make it so that you have a switch to choose boost or reverb ... maybe somebody will do that before I can get to it.
rj

[angelodp]

Mark, very cool Master device. So if I get this right you simply lift the 1k2 wire to pin 3/8 on PI and put in the 25k linear pot with resistor.. presto.


Will this work if I already have a VVR in my amp. I tend to use the VVR in a very minimal way.

Ange

[Zippy]

Mark, very cool Master device. So if I get this right you simply lift the 1k2 wire to pin 3/8 on PI and put in the 25k linear pot with resistor.. presto.


Will this work if I already have a VVR in my amp. I tend to use the VVR in a very minimal way.

Yes, you can combine independent master volumes. RJ has an Rocket with several masters and trimmers - it's a great lil' test bed for ideas.

[angelodp]

Zippy, Mark... have a 50k linear on hand, can you suggest the proper resistor for that or is it to high a value.

Also this will work with EL84's ?

[M Fowler]

The 50kL just gives a wider range of control of the PI which is what the watts control is doing. It is not a MV control but rather a pot controlling voltage to the PI. It works very well in the Rocket, I didn't like it in the Express and I tried 25kL and 50kL in the Express.

33k resistor is used.

Colossal will have to comment regarding use of both MV and Watts control as well as VVR. I have never used a VVR in any amp and I have never run both a MV and watts control in same amp but Colossal has.

Mark

[M Fowler]

Following up on some changes made to this amp since it's creation.

I changed this amp over to foot switch boost jack on front side replacing the mini toggle switch there. Nice to be able to foot switch this puppy now.

Should make a better faceplate but it has gone through so many changes and people rather enjoy the rough look.

This was a TW Rocket Reverb with two EL34's cathode bias amp.

Changed the bias resistor to 350R with 220uf/100v bypass cap.

Decreased the 220k V1a plate load resistor to 150k for more headroom and replaced the GZ34 rectifier with SS plug in to increase voltage. The amp is running 6550's now.

[Zippy]

What are the plate voltages on V1? Any inclination to adjust the dropping string to achieve original Rocket preamp voltages?

[Ian444]

Zippy, is there a problem with higher voltages on small signal tubes? Have you listened to that, to me, it sounds cleaner, more detail, even when it breaks up a bit. If its under 200V on the plate, I'm not interested

[M Fowler]

Zippy I measured but did not write them down. I can get the voltages this week the chassis is still out of the cabinet.

I am quite certain they naturally increased since I switched to a SS plug in replacing the 5AR4. I was more concerned about clean head room and power tube bias.

I don't think I am going to change anything but like you said change the dropping string to get the preamp back in line with the original TW Rocket might make for better tone but we enjoy the amp as is.

Mark

[Zippy]

Zippy, is there a problem with higher voltages on small signal tubes? Have you listened to that, to me, it sounds cleaner, more detail, even when it breaks up a bit. If its under 200V on the plate, I'm not interested

"Problem with higher voltages?"? No, no problem, per se. I like the effect of running at tweed voltages. I also like the idea of running tweed preamp voltages and black face output voltages. There certainly exists a low voltage "cliff" below which the tone just turns to garbage and everything gets fizzy but I like the Rocket preamp pretty much as it is.

Thanks, Mark, for your comments.