Hagtech Clarion 2A3 SET

[jmillerdoc]

Hello,
I am in the process of sourcing parts for this build and noticed a descrepency between the parts list at the end of the article (here: http://www.hagtech.com/pdf/clarionarticle.pdf ) and the schematic.

The schematic shows a 10K 10 watt resistor at R7 where as the parts list shows 6.8K 10 watt.

I actually asked Jim Hagerman himself via email and his response.....well, it didn't help much. He basically said it was a good question and he had no idea....probably the 10K.

I was wondering if any out there have built this amp and what they used in the position at R7 or, if possible, might be able to deduce which one it should be. I imagine either one will work but I bet one will work better

Also, if there are any out there who have built this design, any tips, advice, or experience is always helpful.

For those unfamiliar with this amp it was an attempt to create a well designed DHT SET where all of the parts could be sourced from one supplier, namely AES (Antique Electronic Supply).

Personally, I have digressed quite a bit from the original intent as I have sourced higher end parts from many different vendors to include Sonic Craft High-End DIY Audio Parts (very good variety with excellent service, even a very knowledgeable tech who is easily available to talk with!)
Antique Electronic Supply (great source for basic stuff)
HiFi DIY Site - VT4C/211 Power Triode (great prices on great stuff but shipping is a bit high)
Parts ConneXion - The authority on hi-fi DIY parts and components (excellent source but slow service, esp with paypal)

I plan to post some pics and stuff here as this build progresses for those interested as I have not yet seen a builder's thread for this amp.

Thanks for everyones help in advance!
Jeff

[dsavitsk]

It really does hardly matter (10K is blue, 6.8K is red). The 10K will give you slightly lower current, and probably slightly lower distortion.

This is, by the way, a very good place for a plate load CCS. Even a single 10M45 at ~12mA will offer a nice improvement.

[jmillerdoc]

Originally Posted by dsavitsk

This is, by the way, a very good place for a plate load CCS. Even a single 10M45 at ~12mA will offer a nice improvement.

OK then, it is done.

What do you think of this: K & K Audio - Lundahl Transformers, audio DIY kits and more ? I went ahead and bought 4 of these and received them in the mail today. I thought the price was a steal, I have not seen anything similar to this at this pricepoint.

So then 12mA is the sweet spot?

Any other recommendations?

Jeff

[Solardood]

I did build this amp last year but I dropped the project near spring. Have yet to get it running and actually after revisiting I may redo it, not happy with my layout!

[jmillerdoc]

Just completed the chassis. It is all hand built from scratch. The sides are Spanish Modens and the top is laminated White Tiger Maple. I cut 1" x 1/2" slats about 20" long and laminated them together. On the bottom I used some Cherry veneer ply (3 layer) and glued it down to give it more strength across the laminations.

Seen here is all the connectors (Vampire and Connex) and x2 chokes and x2 2.5vct filament transformers. The vent plates for the tube sockets were purchased from VT4C.com. The James 6112HS output transformers are from TCTubes.com (best deal I have found with s/h included). The power transformer is Hammond as well, disassembled ans mounted sideways with a hand built cap out of the same wood as sides and top. Caps are ASC 45uF 370vac. I will parallel these with a 10uF Solen on each side for a total of 100uF as the last caps before the output stage. The 200uF between the 2 chokes will be a combination of Nichicon and Solen as well. I haven't decided on the 100uF called for at the driver stage, depends on how much real estate I have under the chassis as I get going. Either Elna Cerafine or a combination of Solen and ASC.

Hard part is done, the rest is a piece of cake. Should have it done by tomorrow afternoon if all goes well.

Remainder of parts are PRP resistors, Silver wire, Black Gate bypass, and Copper foil in oil coupling caps. I also will be using the K&K audio CCS on the drivers for plate load.

Jeff

[Solardood]

Nice job Jeff! Looks beautiful! I like those vent plates I may go get a set. I did mine with polished aluminum checker plate for an industrial look so they may look good with it. I will take some pics of it when I get a chance and upload it.

Very nice work Jeff!

[bigjppop]

That's a really nice looking chassis; you've done a great job on this.

[alexg]

Looking good!

The ECC99 might not provide enough gain, you might need a preamp with a bit of a gain.

[Solardood]

I can recall that the input on that circuit had to be 2.5V. I also recall a blurb about putting a cap across the input to use a lower preamp signal? I am using memory here which is not always perfect nowadays!

[jmillerdoc]

Originally Posted by alexg

Looking good!

The ECC99 might not provide enough gain, you might need a preamp with a bit of a gain.

In it's original form, you are correct. With a plate load CCS and a bypass cap it is estimated it will run at 2.5vrms which should be adaquate. If it is not I will add a gain stage with another 5687 or even possibly a 26 or 76 globe. I have left enough room on the top to add 2 more tubes, even the vintage globes if I decide to go that route.

Is this the same Alex who has the article on diyaudioprojects.com? I just finished that amp, albeit a bit changed from that circuit, basically the same amp. Wonderful performer!
Jeff