[INDIA] Chassis, knobs, PCB makers

[jethari]

Originally posted by Vivek
Hi guys,
Any new discoveries on the availability of good drivers in India? I feel like building a pair of speakers again. I also intend to try the symasym amp for two channel music. My sub amp plans are still pending.

Vivek

Try www.corrson.com. They are in Bangalore.

[Vivek]

I built MTM towers with Vifa TC18s and D27s four years back. I was looking at something else. Any ideas?

[sagar]

Originally posted by ssmith
A group buy is a nice idea -- or even a group tube amp project that somebody could coordinate?

Just let me know where and when to sign up. Would love to ride on someone's coattails while i learn the ropes.

[gjo]

A relatively easy project to do is an EL 34 push pull amp using a PCB , the design is available on Pete Millet's site. An EL-34 amp will output about 25-35 wpc, enough to drive most speakers, and a quartet of tubes will not cost a bomb. Assuming the trannies (specs for these are not difficult to get) can be sourced from Delta, one needs to find a good source for a presentable chassis. Typically a project like this will have a one year time frame, in my view.

[navin]

Originally posted by gjo
A relatively easy project to do is an EL 34 push pull amp using a PCB , the design is available on Pete Millet's site. An EL-34 amp will output about 25-35 wpc, enough to drive most speakers, and a quartet of tubes will not cost a bomb.

Besides if you use the millet design and need more power you can upgrade to KT88s.

[gjo]

Besides if you use the millet design and need more power you can upgrade to KT88s.

Well that is possible only if the trannies are designed to take any of these tubes-EL 34/6550/KT 88. By merely plugging and playing the different tubes, using the lower rated trannies, one won't , of course, get more power. (I'm not implying you meant that!)

The KT 88 quartet will give significantly more output power-I had one, until recently, which gave 55 wpc. The 6550 is somewhere in between, but supposedly a good compromise, and cost a bit less. A quartet of JJ KT 88s( currently rated the best) costs around $160, whereas Svetlana EL 34s will cost about half.

[navin]

Originally posted by gjo
Well that is possible only if the trannies are designed to take any of these tubes-EL 34/6550/KT 88.

A quartet of JJ KT 88s( currently rated the best) costs around $160, whereas Svetlana EL 34s will cost about half.

Oh yes the trannies would have to be able to handle 50W.

To get going one can make do with EH instead of JJ/Mullard etc..

[sagar]

Originally posted by gjo
A relatively easy project to do is an EL 34 push pull amp using a PCB , the design is available on Pete Millet's site. An EL-34 amp will output about 25-35 wpc, enough to drive most speakers, and a quartet of tubes will not cost a bomb. Assuming the trannies (specs for these are not difficult to get) can be sourced from Delta, one needs to find a good source for a presentable chassis. Typically a project like this will have a one year time frame, in my view.

Had a look at Pete Millet's site and the amplifier you were referring to. Looks very doable and something up the alley for a group buy/project. I agree with you on the timeframe also considering that it will allow purchases to be staggered over the year (less bite out of the wallet). Also, going by the last posts on this thread, there seems to be vendors enough for:
- cases
- knobs
- hifi resistors/capacitors
- transformers
excepting the tubes of course which if bought off the net in a group buy would mean significant savings for all. hope this idea sparks interest among the other readers of this thread too.

[virenb]

Hi all,

Just got introduced to this thread very recently. Some of you DIYers go back quite a few years!

Regarding valve amps, the difficulty earlier was obtaining audio transformers in India. Lots of PA transformers were made, but those had restricted bandwidth good only for the vocal range.

Well, that restriction doesn't apply any more. Delta Transformers in Delhi is fully capable of making high quality audio output transformers, as well as audio interstage transformers. J.P. Singh at Delta (Tel: 011-4102 5375) is the designer, and is well versed in the interleaving techniques of audio transformers. I've worked with them for over 4 years (at Lyrita Audio) and am very happy with their designs. Of course, they make excellent power transformers too.

It's the group buy mentioned above that prompted me to write this. I'm sure Delta will entertain a reasonable order. The transformer is a major cost in a DIY amp - having an Indian supplier is essential.

All the best with the EL34 amp.

Viren

[navin]

Originally posted by virenb

It's the group buy mentioned above that prompted me to write this. All the best with the EL34 amp.

Virenji, it is really good to see you here.

For a group buy I would suggest OPTs that are more flexible than something that will only work with EL34. I would suggest 50-70W OPTs so that those involved could use KT66, EL34, 6550s, KT77, and KT88 with the same OPT.

I have never heard a 300B in PP (have heard a 300B in SE) and wonder if a 300B PP even makes sense (300B sound at a lower cost because of the smaller OPT required).

What do the rest of you think? It is added cost but we get flexibility and hence many more may be insterested (especially those who have the desire for higher SPLs, low sensitivity speakers, or large rooms).

Viren, I would really be interested in what you think of Pete Millet's design. He does strech the 6SN7 a bit, but this migt be ok if one is using CDs only. What about hum and cross talk?