Another "I need an amp recommendation" thread

[woodturner-fran]

Look,

I know you all have read these threads a thousand times. I know that because I searched and looked at a whole heap of them. The problem is that it is really hard to decide. eg: I saw the boozehound amp, thought , yeah this is great, easy to build for a relative beginner, built by others uses widely available tubes, but then saw it was 3WPC!

While it was very informative to read and spend an hour finding out about it, imagine repeating that exercise again and again! My head is starting to melt.

So please help! I need a power amp that will give me about 10-15WPC. It should be PP because I'll be using it with Quad ESLs and PP is meant to sound better. It should use easily available tubes eg 12AX7 and EL34, EL84 or KT88 for example. I'll be using it with a passive pre. Another example is that I looked at SYs red light amp - but the LED array is an added complication (for me!)! So I guess small parts count would help (eg the boozehound one looked great in this regard).

So I need a schematic and if there was a BOM to go with it that would be great. I can solder proficiently, I can make the chassis, I can buy the gear. If there was photo instructions along the was to help with transfer of schematic to real life, that would be great, but not a deal killer. It must sound good!!!!!!

Anyone out there who can offer help?

thanks,
Fran

[EC8010]

PP EL84 is the obvious answer. Don't let all those LEDs in SY's RLD put you off - once you've worked out which end of your LED is which, all you require is patience in soldering them together.

If I can make a dovetail joint, you can solder LEDs...

[Eli Duttman]

Fran,

Check out "El Cheapo". It's simple and set up ultralinear "12" W. O/P tubes will yield the power you need. As drawn, 'AQ5s (6V6 "equivalent") are used. Changing the PP pair's cathode resistor allows the circuit to work with EL84s. The 12AT7/ECC81 is in production and good NOS is still affordable.

If you have the patience, read the entire lengthy thread.

[planet10]

We built a 4 W variation of El Cheapo (triode wired Class A EL84 using a Scott LK48 donor) and it is superb. I look forward to hearing a RLD (the one headed to UKdiy is supposed to come up here... and we plan on doing a cross between El Cheapo (differential front-end) and RLD (LED biased output stage)

Both of these have about the same level of complexity... and if you want to make it simplier, UL wire the outputs (to eliminate the screen regs on the RLD) and add a hefty B- for the diff pair (eliminates the CCS in El Cheapo). They are both probably better with the SS (reg or CCS), but you can always add it later.

Except for the triode wired part Poinz's 6V6 is an example of the simple approach (for more power a UL OPT with screens tied to the UL tap thru a screen stopper resistor)

http://www.audiotropic.net/MachineUs...ersManual.html

(i consider EL84/6V6/6AQ5 to be roughly interchangable -- as Eli mentioned bias resistors change value)

dave

[woodturner-fran]

OK,

many thanks to everyone. It seems that for me it looks like I should either go for the RLD EL84 or el cheapo. I will arise and go now, and go to read the threads......






but like arnie says, I'll be back!


Fran

[jkeny]

Hi Fran,
As you probably have read my posts in the tube section I highly recommend the "Baby Huey" as a simple build.

I can lend you the amp to listen to in your own system so you can judge. I don't know how it compares with "El Cheapo" - mine is built using ECL86 tubes recycled from Rogers Cadet.

It can also be built using ECL84 tubes - in either case it is a easy build.

Don't know if this helps?

JOhn

[woodturner-fran]

Well, I suppose today can mark the start date for this project!

I just bought some EL84s and some 9 pin tube sockets from ebay!

Looking at the schematics, I'm still undecided. Next I'm going to get a suitable PX. I'm kinda leaning towards SY's RLD but having John with a Baby Huey close by is very tempting. The only reason I haven't jumped on it is that my current amp is an ECL86/12AX7 job (and very good it is too), so I suppose I want something different.

A question for SY or RLD owners. I read in SY's article in Baz Hornemans mag that it is designed for 2V input to get a full 10W. Now I'm planning on using a passive pre with this as a power amp. My CDP puts out 2V, so do most things, but my phono stage I'd say would be a little lower (its a VSPS from RJM - see analogue section). I'm using ESL 57s as speakers. Will it be OK?


Fran

[SY]

I'm using mine on ESLs, as it happens. Seems to be a good match. If the sensitivity is too low, you can always drop the feedback a little bit by increasing the size of the 6k8 feedback resistor. But I'd try it just as-is first and make the change if you can't get enough volume.

[woodturner-fran]

SY, those ESLs are something aren't they! I've had wuite a few people with more expensive speakers walk away unhappy!


Anyway a Q for you,

Looking at using a PTx with a secondary of 230V. MJ reckons taht I should end up with about 285VDC after rectifiaction and regulation etc. Would this be enough to run the RLD?

(see cross post in transformer thread)

Fran

[jkeny]

Hi Fran,
Why don't you try the LED array on the ouput cathode of an existing amp - the ECL86 for instance? I think the LEDs are the major innovation in the RLD amp - SY can confirm?

John