Recommendations for a SS RIAA phono preamp?

Reffc · Post by **Reffc** » Mon Oct 21, 2013 2:30 pm

I'm looking for a (relatively) straightforward project to build a phonostage for my Garrard 401 rather than have to keep swapping duties with my Gyro. Soldering skills are good and I have a fair bit of kit tools-wise except for a scope.

Any recommendations sub £150 for a complete kit or a PCB/instructions which I can mate to a transformer? Happy to build an enclosure or to use a supplied one.

Ali Tait · Post by **Ali Tait** » Mon Oct 21, 2013 3:03 pm

You could try this-

http://www.hagtech.com/bugle2.html

Reffc · Post by **Reffc** » Mon Oct 21, 2013 9:04 pm

Thanks Ali

already had a look at the Bugle 2. Looks like a well respected kit..just a little pricey for what you get but guess the guy has to make a living. It's on my list!

JamesD · Post by **JamesD** » Mon Oct 21, 2013 9:23 pm

On DIYaudio there are several exceptional RIAA preamp designs from Sales Simple JFET RIAA to Joachim Gerhard designs with John Curls Blowtorch inbetween.

I would build any of these - of course these are not kits and, in many cases, PCBs aren't available but the final design performance is, in most cases, right up there with the best SS designs...

And then there is SYs His Masters Noise in the articles section for a Valve pre...

J

Reffc · Post by **Reffc** » Tue Oct 22, 2013 3:10 pm

Thanks James, I'll check them out. Not too concerned whether valve or SS, providing they perform well. A circuit diagram is fine as long as I have the values and what goes where.

IslandPink · Post by **IslandPink** » Tue Oct 22, 2013 6:26 pm

We've got more valve phono suggestions on here than you could shake a stick at . I suppose the PCB bit is where we'd fall down as most things built on here are real DIY point-to-point jobs, but not all of them. We could narrow that question down if you let us know if it's MC or MM ; if MC, then step-ups ( too expensive?) or SS head-amp, and overall gain .

Nick (G) has quite a nice unit out there ( now commercial ) that has a PCB, but not sure if he'd sell you a spare PCB ..... but that's very good, and uses a jFET / ECC88 cascode as the input, avoids step-ups, has great bass and not a lot of parts cost.

Reffc · Post by **Reffc** » Wed Oct 23, 2013 2:28 pm

IslandPink wrote:We've got more valve phono suggestions on here than you could shake a stick at . I suppose the PCB bit is where we'd fall down as most things built on here are real DIY point-to-point jobs, but not all of them. We could narrow that question down if you let us know if it's MC or MM ; if MC, then step-ups ( too expensive?) or SS head-amp, and overall gain .

Nick (G) has quite a nice unit out there ( now commercial ) that has a PCB, but not sure if he'd sell you a spare PCB ..... but that's very good, and uses a jFET / ECC88 cascode as the input, avoids step-ups, has great bass and not a lot of parts cost.

Its for a MM input. I have a few decks, but my main deck is being set up to demo Zyx carts so I'd like to use my 401 into a MM stage and avoid all the faffing about with constantly swapping inputs to my current phonostage. I wanted to couple this need with a project, so a simple but high performance SS design seemed the way to go. Bugle 2 seems to be top of the pile at the moment unless there's a circuit which could be snaffled and built up on a prototyping board with little difficulty. Nicks is of interest but I'd shy off from asking to pinch a commercial venture design!

Neal · Post by **Neal** » Wed Oct 23, 2013 5:23 pm

There's this old HFW phono Stage based on a pair of opamps:

https://www.dropbox.com/s/joe2zgv5csr9h ... _Phono.pdf

CCt shown is for MC. IC1 is AD797, IC2 AD743

For MM lower R3 to 5K6 and change R1 to 47K, place a 100pF cap in parallel. IC1 and IC2 should be AD743.

C1 can be tuned to alter the Bass roll off. Quality of C1 is important as well, make it a good 'lytic cap as it has quite an impact on the sound.

I built the cct ages ago and ran it off batteries...my layout sucked though and it did hiss a bit but otherwise it was OK.

Reffc · Post by **Reffc** » Wed Oct 23, 2013 6:07 pm

Thanks Neal, great find...looks interesting.

Excuse my ignorance, but what does the BR1 and MC78L15 and MC79L15 refer to?
Looking at the data sheet for the AD743, it's not a twin channel chip and presumably the NC and Null are just cross connected to the output or not in circuit at all?

pre65 · Post by **pre65** » Wed Oct 23, 2013 6:18 pm

BR = Bridge rectifier

The other two are voltage regulators. Google the numbers for more info.

Mike H · Post by **Mike H** » Wed Oct 23, 2013 6:54 pm

It's the power supply.

Greg · Post by **Greg** » Wed Oct 23, 2013 7:06 pm

I've just emailed Paul the complete articles from the original HFW DIY supplements.

pre65 · Post by **pre65** » Wed Oct 23, 2013 7:07 pm

Greg wrote:I've just emailed Paul the complete articles from the original HFW DIY supplements.

What one is it in Greg ?

Greg · Post by **Greg** » Wed Oct 23, 2013 7:55 pm

I think they are Nov 93 and April 94. I can email them to you if you want.

pre65 · Post by **pre65** » Wed Oct 23, 2013 8:00 pm

Greg wrote:I think they are Nov 93 and April 94. I can email them to you if you want.

I have not got those in my pile, but I will check the Gold disc to see if they are on there.

audio-talk

Recommendations for a SS RIAA phono preamp?

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