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After almost a year of planning and gathering parts, I finally finished my Lightning 15. I built the cleaned up version with the changes listed in the latest revision. I am in the process of building a cabinet and deciding what speakers to use. I have been trying it out with the speakers of the other 3 amps I built. I am using a Hammond 270FX that is supposed to put out 275v but I measured almost 305v AC coming off of the red leads. I have read somewhere that Hammond Transformers are rated very conservatively. The amp sounds good but I think my voltages are a bit high:

Pin | 1 2 3 4 5 6 7 8 9
-----|--------------------------------------------
V1 | 146 --- 1.54 --- --- --- --- --- ---
V2 | 173 --- 1.6 --- --- 296 173 179 ---
V3 | 257 29 74 --- --- 257 27 74 ---
V4 | --- --- 8.35 --- --- --- 381 --- 239
V5 | --- --- 8.35 --- --- --- 382 --- 239
V6 | --- --- --- ---- --- --- --- 390 ---

The Cap voltages, starting at the transformer end are:
390, 238, 349, 390, 296, and 360.

I am using a Sovtek 5AR4 rectifier. I also have a GE 5R4GA, a GE 5Y3GT and a JAN CHS 5Y3GTA rectifier tubes and was wondering if I should be using one of these to drop the voltage. What do you all think? Any suggestions or comments would be appreciated.

Thanks,

Dan

Well, first, congratulations on building an working amp. and that you think it sounds good.

Yes, I think you should try to drop the voltages. Try the 5Y3 and remeasure. Someon else was looking to drop their voltages recently and there are threads on the forum about that.

For voltage ideas, check out: viewtopic.php?t=579&highlight=voltage

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

I remeasured the voltages with both the 5Y3 and the 5R4. Here they are:

5R4
Pin | 1 2 3 4 5 6 7 8 9
-----|--------------------------------------------
V1 | 122 --- 1.51--- --- 122 --- 1.5.14---
V2 | 156 --- 1.49 --- --- 270 156 162 ---
V3 | 233 26.5 67 --- --- 233 25 67 ---
V4 | --- --- 8.35 --- --- --- 341 --- 201
V5 | --- --- 8.35 --- --- --- 342 --- 201
V6 | --- --- --- ---- --- --- --- 354 ---

The Cap voltages, starting at the transformer end are:
354, 200, 314, 351, 266, and 323.

5Y3
Pin | 1 2 3 4 5 6 7 8 9
-----|--------------------------------------------
V1 | 127 --- 1.43 --- --- 127 --- 1.43 ---
V2 | 148 --- 1.43 --- --- 258 149 153 ---
V3 | 223 25.4 65 --- --- 223 24 65 ---
V4 | --- --- 7.2--- --- --- 335 --- 210
V5 | --- --- 7.2--- --- --- 335 --- 210
V6 | --- --- --- ---- --- --- --- 345 ---

The Cap voltages, starting at the transformer end are:
343, 210, 305, 341, 258, and 313

It looks like the voltages are more in line and I like the sound of the 5R4 better than the 5Y3. My voltages seem a bit low on V2, Pin 2 and 7 with all 3 rectifiers. Is this a problem?

I am also experimenting with various speakers and so far I like the sound of the Jensen P10Rs over the C10Q and P12Q. I am going to try mixing the 10s (P10R with a C10Q) to see if that is the combination I will go with.

Let me know what you all think.

Thanks,

Dan

Your voltages look fine. Can you measure your Mains voltage for reference? Here's some to compare to.

viewtopic.php?t=151

Speakers: For 2-10" I liked the Jensen Alnico P10Q in a twin config, but put BBQ 10" Alnico in the end. Today, I'd use a 2-10" Tone Tubby Bomb or twin Alnico.

2-10 is a nice combination for that amp IMO and mixing them up is good.

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

I measured my mains voltage and am getting between 123 to 123.5 volts. Could this be causing the high readings I am getting from the Hammond 270FX? According to the link posted above, some of us here in the US are getting readings even higher than mine.

Dan

Might be a few percentage points up. 120 is the standard nominal so maybe 3% higher on the HV?

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