Dahlquist DQ LP1

[InfernoSTi]

Originally Posted by soundalot

I missed clicking on DQ LP1 image. I prefer to do the upgrade myself. I do not need them to upgrade other parts e.g. loading resistors.When I purchased the DQ LP1 from Larry Smith many parts were upgraded.

Doing it yourself equals twice the satisfaction. Please post your results as I am very interested. I just bought a stock DQ LQ1 last week and have been trying to figure out the upgrade path myself.

I have an acquaintance, Doak, who first told me about the unit (he uses one) and I've been looking for one for about a year. Just now found one at a good price (#754, actually). It needs some care and attention, though.

Anyway, if you have good luck with the opamps, please post!

John

P.S. I know I'm new here...I hope I add some value over time!

[soundalot]

There is a good bit of information regarding upgrades for the DQ LP1 on various websites. The first mod is to replace the RCA jacks as they are made poorly made and can be intermittent. Check on the quality of the components in the passive network

[mikebarney]

I upgraded my DQ-LP1 last year, replacing the RCAs, as well as all Rs and Cs. I tried replacing the ICs with OPA2604s, but the power supply voltages dropped to approx +/-11 volts (way out of +/-15V regulation). Turns out that the OPA2604 draws 10.5mA each for a total of 52.5mA for 5 ICs, versus the stock draw of 5mA for the stock 4558 ICs, which have a total draw for all 5 ICs of only 25mA. Note that the stock transformer is only a 35mA capacity unit. The lesson: Without changes to the transformer, look for low current draw ICs as replacements. Looks like the OPA2107 might be one good choice at 4.5mA.
Mike

[soundalot]

Thanks for the reply. Looks like the choice is between NE 5532 and OP2107. What are you using the LP 1 with? What xover point are you using?

[mikebarney]

Looks like the NE5532 is 8mA each or 40mA for all 5 ICs, exceeding the transformers 35mA capacity.
I use the crossover with a variety of DIY woofers, mostly at low (<50Hz) crossover frequencies.
Mike

[soundalot]

I spoke with an engineer at AD. He suggested AD8066. 0r for less bandwidth 8599.He also suggested OP270. Have to check current draw and see if these fit parameters(35ma). Someone on another site built a much beefier external p.s. .

[MagicMarksy]

Re: Dalquist DQ-LP1

I got one today.
No schematics.
No manual.
Can you send me anything that would help me.

I would really appreciate it.

Michael A. Marks, MD
539 Briarwood Drive
Clarksville, TN 37040

(931) 561-1668

E-Mail: MichaelAlanMarks@aol.com


Please

[bobrown14]

Originally Posted by MagicMarksy

Re: Dalquist DQ-LP1

I got one today.
No schematics.
No manual.
Can you send me anything that would help me.

I would really appreciate it.

Michael A. Marks, MD
539 Briarwood Drive
Clarksville, TN 37040

(931) 561-1668

E-Mail: MichaelAlanMarks@aol.com


Please

There's a Dahlquist user group over at Yahoo. They've got a files section with schematic and user manual in PDF for this unit.

Cheers,
Bob

[mikebarney]

I put together a webpage with the reference materials I have for the DQ-LP1, including schematic, instruction manual, and a couple reviews.

https://sites.google.com/site/mpbarn...hlquist-dq-lp1

Mike

[Harpy]

What about AD712JN op amps?