Tubes in an api 500 series module

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

pucho812

Well-known member
Joined
Oct 4, 2004
Messages
14,832
Location
third stone from the sun
well I have a 583 in front of me... they claim a custom part that after doing some searching looks like a dc to dc converter from xp audio.
They also have 2 ic chips in there. One is a 2134 and the other a that 1646. with input and output transformers, I wonder what the that chip is doing.
Since it runs a single 12ax7 I assume the opa chip is for more gain. I should trace this out and see.
 
Last edited:
If I remember correctly...There's some in-depth conversation on tweaking the Maxim circuit to generate the HT in the G9-51X thread.

I think a couple of good GDIY building blocks would be a DC-DC converter for use in 500/51X that can generate HT and heater as well as a SMPS design for HT and heater for outboard that could power a couple of typical bottles.
 
I think a couple of good GDIY building blocks would be a DC-DC converter for use in 500/51X that can generate HT and heater as well as a SMPS design for HT and heater for outboard that could power a couple of typical bottles.
One problem I see is the official VPI Alliance specs (from API) says maximum draw from either PSU rail is 130 mA max. A 12AX7, as an example, pulls 150 mA for the heater when wired for 12V operation.

Bri
 
One problem I see is the official VPI Alliance specs (from API) says maximum draw from either PSU rail is 130 mA max. A 12AX7, as an example, pulls 150 mA for the heater when wired for 12V operation.

Bri
From the Tubecore manual:

« The current consumption of the TUBECORE 500 is rated at 400 miliamperes per slot. The unit takes up two rack spaces. Please check with the rack manufacturer that the design can meet this rating »

Far from API’s specs :LOL:
 
Well, my point is the slot rating specified by API is 130 mA per rail. <shrug> I guess someone could design a module pulling 20 Amps if the rack could withstand it. lol

Bri
 
One problem I see is the official VPI Alliance specs (from API) says maximum draw from either PSU rail is 130 mA max. A 12AX7, as an example, pulls 150 mA for the heater when wired for 12V operation.

Bri
Very true. I believe most tube modules in VPR spec take up two slots unless they're running out of spec or maybe using a lighter load tube.
 
Scott Lachapell:

« In the end, the 583s mk2 pulls between 115ma and 120ma max. This range is due to the variances between individual vacuum tubes installed. »

I guess they really did their homework.
 
Well, my point is the slot rating specified by API is 130 mA per rail. <shrug> I guess someone could design a module pulling 20 Amps if the rack could withstand it. lol

Bri
there are many 500 modules that doesn't adhere to VPR spec. But there are options to tackle the situation. You can use a non API rack which provides more current per slot, or short load an API rack.. from a design side, they can have the module be double wide taking up two slots to have more durrent draw available to run their electronics. AMS neve and their 500 series version of RMX16 iirc is three slots wide.
 
Tube into hi-Z op amp which is used to drive THAT part properly, which is prob driving a 1:1 output
It’s not.
the chip on the block diagram shows it after the tube. It’s also not a 2134, I had that part wrong. It’s an opa iirc 227. I can reopen it again. It’s a single opamp in a dip8. The that corp chip was correct.
 
Back
Top