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Anyone know the differance in voltage drop between a single GZ34 vs Two 5V4's??? Specifically in a Matchless DC-30.

Also the effect on tone, output and dynamics between the two.

Thanx. Cal

Never done this. I guess it would depend on the configuration. How would these be connected? If in parallel, I would expect the drop of one. If in series, the drop of two??

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

CoCo, The Matchless DC-30 schematic I have has 345 volts for the B+, but what is not clear is if it is with the single GZ34 or the pair of 5V4's. The schematic shows two sockets and states "One GZ34 or two 5V4's" on the drawing. 5V4's not only have more voltage drop and sag, but also have a lower current capability so two are needed to feed a DC-30.

I'll assume the +345 Volts is with the GZ34 and the pairs of 5V4's wired in parallel will have more voltage drop and sag. (At this time I do not know the B+ on a Lightning or what the additional voltage drop is with a pair of 5V4's, but I'm hoping its 325-330 volts like on an AC30.) I believe two 5V4's in parallel will have half the voltage drop of a single 5V4.

The user's manual that I downloaded off the Matchless website says the GZ34 is more aggressive and the pair of 5V4's smoother. I imagine the results would be similar to those stated on the tread about using a 5U4 on a Lightning, but without the stressful heater current issue. Matchless designed their PS tranny to have ample current for this config. The tranny I ordered from you will be expoited in this manner. Maybe even a single 5U4 could be used.

I wonder if many would be interested in a new hybred that I'm creating. I'll call it a HC-30/15. The idea is to have the front end of a DC-30 and for power a choice of 30 or 15 watts.

What distinguishes my amp from the Matchless is the power would be set by physically pulling out a pair of EL84's, changing rectifier tubes and changing the output impedance to avoid a mismatch and provide smoothness. Matchless utilizes a switch to float the cathodes of two EL84's and change the fixed bias resistor value. No change of output impedance is done by this switch.

Thirty watt iron would be used for the PS and output on my amp. The quad of EL84's would have paired cathodes and each pair would have its 120 ohm resistor and 25uf caps like a lighting. I'm using a Vox Albion clone tranny for the output. The big output iron would give the added clean headroom like I read about in an other post about your Lightning. In effect it would be like a Lighning on steroids with the DC-30 front end and the heavey iron.

Cal

Very interesting concept. B+ 340-350 is normal for a Lighting with the GZ34. I plan to measure mine and post it.

The GZ34 will be more aggressive in any event.

Is your plan to have two channels - 12AX + EF-86 as well as all the cut controls etc?

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

CoCo, Yes to parallel triode and Ef-86. If you want I could send you the DC-30 schematic I have to you via snail-mail. Let me know. Everything would be very clear and possibly could be posted as a referance for everyone on this forum. The date I have on my schematic is 1997, when Mark Sampson was still with Matchless.

I'm using the old pre-97 six way switching on the EF-86. BadCad today uses a 5-way. Also the master volume is switched into the circuit by a pull switch. Very similar to a Lighning in many ways and not that big a jump up in complexity. I'm not going to add the speaker phase switch or the effects loops that simply splice into the circuit before the driver. No need for an Edison plug either for 120volts AC.

The way I see it if I'm building a HC-15 it takes very little effort to make a HC-30/15. The only cost penalties besides the heavier iron is of a few components like two extra tube sockets, resisistors and caps. Not a lot of extra real estate is needed either for two extra EL84's and an extra octal for dual 5V4's. Still is going to be about a fifty pound head though, mostly fat trannies.

I'm using sozo caps even though not recomended by some on this forum. I'm just experimenting and trying to make it more voxy.

Yes, a plug-in in, and it didn't differ significantly from the GZ34.
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I assume the results would be comparable to those described on the thread regarding words from letters