Information on Pyramid Power Supplies

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Power Supplies
Compiled and Maintained by Robert Meister WA1MIK (SK)
Web page currently maintained by Mike Morris WA6ILQ

Click here or the icon above for the Pyle USA web page.

At one point the products were being sold by "Quality Car Audio" and it would seem that they're trying to get rid of a LOT of Pyramid stock, as there are deep discounts on their web page: https://www.qualitycaraudio.com/. Don't even bother going to either site. Go to the one below instead.

Later I found that product support has been taken over by https://www.pyleusa.com/ and they too are offering deep discounts on Pyramid products.

The https://www.pyleaudio.com/Home.aspx web site seems to be an even better source. I don't know if this is related to PyleUSA.

The design of the Pyramid linear regulated power supplies is very similar to the Astron RS and VS series. They're based on the popular LM723 voltage regulator IC and use multiple high-power series-pass transistors in parallel to supply current to the load. Some people say the Pyramids are engineered better. The larger supplies have regulator circuitry that's almost identical to their Astron cousins. Pyramid ammeters measure the voltage drop across a single shunt resistor in series with the positive output, whereas Astron ammeters measure the drop across one of the series-pass transistor emitter balancing resistors. This makes the Pyramid ammeter track the actual load current more accurately, especially if one of the series-pass transistors fails.

The "gold series" appears to be a cheaper version since they use zener diodes instead of the venerable µa723 integrated circuit regulator of other models.

Power Supply Manuals:

The numerical value in the model number indicates the peak intermittent current capability. Some model numbers have "K" for the suffix while others have "KX".

The support group told me:

"PS-nnK supplies are the older version. The updated version assembled by the new factory is PS-nnKX. The boards and features are different but both models share the same specs."

Astron uses suffix letters to indicate metering, battery back-up, and other options; not so with Pyramid. Some supplies always have meters while others never do. TENNA seems to be a brand name associated with the Phase III products; it may have been bought by Pyramid. Don't be surprised if your unit's parts values and even connections do not agree with the schematic. They made lots of changes and documentation upkeep was apparently not a priority.

If anyone has manuals as PDF files (or hard-copy that we can scan) for any models that we do NOT have, please consider sending them in to the page maintainer listed at the top of this page.

PS-3KX 3A Regulated Power Supply 215 kB PDF file
Has schematic with parts values.

PS-4KX 4A Regulated Power Supply 215 kB PDF file
Has schematic with parts values.

PS-7KX 7A Regulated Power Supply 215 kB PDF file
Has schematic with parts values.

Tenna PS-7 7A Regulated Power Supply schematic
This supply uses 2N2222 transistors on the circuit board. These are the same as PN2222 but are NOT the same as P2N2222; those have a different lead configuration (CBE).

PS-8KX 8A Regulated Power Supply 215 kB PDF file
Has schematic with parts values.

PS-9KX 9A Regulated Power Supply 275 kB PDF file
With cigarette jack and schematic with parts values.

PS-12K 12A Regulated Power Supply 338 kB PDF file
Has schematic with parts values.

PS-14K 14A Regulated Power Supply 356 kB PDF file
Has schematic with parts values.

PS-15K 15A Regulated Power Supply 347 kB PDF file
Has schematic with parts values.

Manual for the PS-3G, PS-4G, PS7G Regulated Power Supplies 11.5 MB PDF file courtesy of Ron Wagner WD8SBB.
Has schematic and parts list.

Tenna PS-20 20A Regulated Power Supply schematic

PS-21K 21A Regulated Power Supply 277 kB PDF file
With ammeter, DC fan, and schematic with parts values.

PS21KX Basic Circuit Diagram 380 KB PDF file
Like it says, "basic".

PS-25 "Phase III" 25A Regulated Power Supply 44 kB PDF file
With ammeter, voltmeter, crowbar, and overload indicator (buzzer). Has schematic but no parts values.

PS-26KX 26A Regulated Power Supply 349 kB PDF file
With ammeter, voltmeter, crowbar, DC fan, and overload indicator (buzzer and LED). Has schematic with parts values.

PS-32LAB 30V 5A Lab Power Supply 260 kB PDF file
No schematic.

PS-35 "Phase III" 35A schematic only 16 kB PDF file
With ammeter, voltmeter, and crowbar. No parts values. See the PS-25 "Phase III" manual above as it's nearly identical.

PS-35 "Phase III" 35A Regulated Power Supply 172 kB PDF file
With ammeter, voltmeter, and crowbar. Has schematic and parts list. Submitted by Ralph WA2PUX.

PS-35G 35A Power Supply 420 kB PDF file
With ammeter, voltmeter, crowbar, and alarm. Schematic with parts values.
Drawn by Carl Hallberg W9CJH. The PDF also has three recommendations for improvement.

PS-35G 35A Power Supply 480 kB PDF file
Identical to above but includes interconnection plugs and jacks.

PS-35G 35A (Gold) Power Supply 972 kB PDF file
Donated by John Roccaro KN3I Includes interconnection plugs and jacks. Much easier to read and follow than some of the above.

PS-36K 36A Regulated Power Supply 325 kB PDF file
With ammeter, voltmeter, crowbar, and DC fan. Has schematic with parts values.

PS-46KX 46A Regulated Power Supply 220 kB PDF file
With ammeter, voltmeter, and crowbar. Has schematic with parts values.

PS-52K 52A Regulated Power Supply 332 kB PDF file
With ammeter, voltmeter, crowbar, and DC fan. Has schematic with parts values.

PS-52KX 52A Regulated Power Supply 100 kB PDF file
With ammeter, voltmeter, crowbar, and DC fan. Has schematic with parts values.

PS-64KX 64A Regulated Power Supply 216 kB PDF file
With ammeter, voltmeter, crowbar, and AC fan. Has schematic with parts values.

PSV-40 3A Switching Power Supply 225 kB PDF file
With cigarette jack. No schematic, which is typical of switching power supplies.

PSV-200 20A Switching Power Supply 133 kB PDF file
No schematic, which is typical of switching power supplies.

PSV-300 30A Switching Power Supply 404 kB PDF file
No schematic, which is typical of switching power supplies.

Pyramid Power Supply Feature Matrix:

Key to Columns:

Sch - Schematic
PV - Parts Values
VM - Volt Meter
AM - Amp Meter
Fan - Fan (AC or DC if known)
OLI - Over-Load Indicator (LED and/or Buzzer)
CLJ - Cigarette Lighter Jack

Model Number Sch PV VM AM Fan OLI CLJ

PS-3KX 3A Yes Yes

PS-4KX 4A Yes Yes

PS-7KX 7A Yes Yes

PS-8KX 8A Yes Yes

PS-9KX 9A Yes Yes Yes

PS-12K 12A Yes Yes Yes

PS-14K 14A Yes Yes Yes

PS-15K 15A Yes Yes Yes Yes

PS-21K 21A Yes Yes Yes DC Yes

PS-25 "Phase III" 25A Yes Yes Yes Yes

PS-26KX 26A Yes Yes Yes Yes DC Yes

PS-32LAB 30V 5A Lab PS Yes Yes Yes

PS-35 "Phase III" 35A Yes Yes

PS-35G 35A Yes Yes Yes Yes Yes

PS-36K 36A Yes Yes Yes Yes DC

PS-46KX 46A Yes Yes Yes Yes

PS-52K 52A Yes Yes Yes Yes DC

PS-52KX 52A Yes Yes Yes Yes DC

PS-64KX 64A Yes Yes Yes Yes AC

PSV-40 3A Switching PS Yes

PSV-200 20A Switching PS Yes

PSV-300 30A Switching PS Yes

Model Number	Sch	PV	VM	AM	Fan	OLI	CLJ
PS-3KX 3A	Yes	Yes
PS-4KX 4A	Yes	Yes
PS-7KX 7A	Yes	Yes
PS-8KX 8A	Yes	Yes
PS-9KX 9A	Yes	Yes					Yes
PS-12K 12A	Yes	Yes				Yes
PS-14K 14A	Yes	Yes				Yes
PS-15K 15A	Yes	Yes				Yes	Yes
PS-21K 21A	Yes	Yes		Yes	DC	Yes
PS-25 "Phase III" 25A	Yes		Yes	Yes		Yes
PS-26KX 26A	Yes	Yes	Yes	Yes	DC	Yes
PS-32LAB 30V 5A Lab PS			Yes	Yes		Yes
PS-35 "Phase III" 35A	Yes		Yes
PS-35G 35A	Yes	Yes	Yes	Yes		Yes
PS-36K 36A	Yes	Yes	Yes	Yes	DC
PS-46KX 46A	Yes	Yes	Yes	Yes
PS-52K 52A	Yes	Yes	Yes	Yes	DC
PS-52KX 52A	Yes	Yes	Yes	Yes	DC
PS-64KX 64A	Yes	Yes	Yes	Yes	AC
PSV-40 3A Switching PS							Yes
PSV-200 20A Switching PS					Yes
PSV-300 30A Switching PS					Yes

Pyramid Power Supply Articles:

PS-15KX Regulated Power Supply Evaluation by Robert Meister WA1MIK (SK)
Build quality and load testing.

Pyramid PS-21KX Regulated Power Supply Repair by Rich Post KB8TAD (offsite link)
Includes theory and circuit analysis. (local copy)

Pyramid PS-25 (Phase III) Regulated Power Supply Repair by Rich Post KB8TAD (offsite link)
Includes theory and good troubleshooting information. (local copy)

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This page initially created 12-Sep-2015 from Other Mfgrs.

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.

	PS-3KX 3A Regulated Power Supply 215 kB PDF file Has schematic with parts values.
	PS-4KX 4A Regulated Power Supply 215 kB PDF file Has schematic with parts values.
	PS-7KX 7A Regulated Power Supply 215 kB PDF file Has schematic with parts values.
	Tenna PS-7 7A Regulated Power Supply schematic This supply uses 2N2222 transistors on the circuit board. These are the same as PN2222 but are NOT the same as P2N2222; those have a different lead configuration (CBE).
	PS-8KX 8A Regulated Power Supply 215 kB PDF file Has schematic with parts values.
	PS-9KX 9A Regulated Power Supply 275 kB PDF file With cigarette jack and schematic with parts values.
	PS-12K 12A Regulated Power Supply 338 kB PDF file Has schematic with parts values.
	PS-14K 14A Regulated Power Supply 356 kB PDF file Has schematic with parts values.
	PS-15K 15A Regulated Power Supply 347 kB PDF file Has schematic with parts values.
	Manual for the PS-3G, PS-4G, PS7G Regulated Power Supplies 11.5 MB PDF file courtesy of Ron Wagner WD8SBB. Has schematic and parts list.
	Tenna PS-20 20A Regulated Power Supply schematic
	PS-21K 21A Regulated Power Supply 277 kB PDF file With ammeter, DC fan, and schematic with parts values.
	PS21KX Basic Circuit Diagram 380 KB PDF file Like it says, "basic".
	PS-25 "Phase III" 25A Regulated Power Supply 44 kB PDF file With ammeter, voltmeter, crowbar, and overload indicator (buzzer). Has schematic but no parts values.
	PS-26KX 26A Regulated Power Supply 349 kB PDF file With ammeter, voltmeter, crowbar, DC fan, and overload indicator (buzzer and LED). Has schematic with parts values.
	PS-32LAB 30V 5A Lab Power Supply 260 kB PDF file No schematic.
	PS-35 "Phase III" 35A schematic only 16 kB PDF file With ammeter, voltmeter, and crowbar. No parts values. See the PS-25 "Phase III" manual above as it's nearly identical.
	PS-35 "Phase III" 35A Regulated Power Supply 172 kB PDF file With ammeter, voltmeter, and crowbar. Has schematic and parts list. Submitted by Ralph WA2PUX.
	PS-35G 35A Power Supply 420 kB PDF file With ammeter, voltmeter, crowbar, and alarm. Schematic with parts values. Drawn by Carl Hallberg W9CJH. The PDF also has three recommendations for improvement.
	PS-35G 35A Power Supply 480 kB PDF file Identical to above but includes interconnection plugs and jacks.
	PS-35G 35A (Gold) Power Supply 972 kB PDF file Donated by John Roccaro KN3I Includes interconnection plugs and jacks. Much easier to read and follow than some of the above.
	PS-36K 36A Regulated Power Supply 325 kB PDF file With ammeter, voltmeter, crowbar, and DC fan. Has schematic with parts values.
	PS-46KX 46A Regulated Power Supply 220 kB PDF file With ammeter, voltmeter, and crowbar. Has schematic with parts values.
	PS-52K 52A Regulated Power Supply 332 kB PDF file With ammeter, voltmeter, crowbar, and DC fan. Has schematic with parts values.
	PS-52KX 52A Regulated Power Supply 100 kB PDF file With ammeter, voltmeter, crowbar, and DC fan. Has schematic with parts values.
	PS-64KX 64A Regulated Power Supply 216 kB PDF file With ammeter, voltmeter, crowbar, and AC fan. Has schematic with parts values.
	PSV-40 3A Switching Power Supply 225 kB PDF file With cigarette jack. No schematic, which is typical of switching power supplies.
	PSV-200 20A Switching Power Supply 133 kB PDF file No schematic, which is typical of switching power supplies.
	PSV-300 30A Switching Power Supply 404 kB PDF file No schematic, which is typical of switching power supplies.

	PS-15KX Regulated Power Supply Evaluation by Robert Meister WA1MIK (SK) Build quality and load testing.
	Pyramid PS-21KX Regulated Power Supply Repair by Rich Post KB8TAD (offsite link) Includes theory and circuit analysis. (local copy)
	Pyramid PS-25 (Phase III) Regulated Power Supply Repair by Rich Post KB8TAD (offsite link) Includes theory and good troubleshooting information. (local copy)