Transcendent Sound GG Preamp

[mgalusha]

That's a fully passive design, isn't it?

Nope, it's an active line stage.

[bpape]

Hmmmm.  Interesting.

Bryan

[Bunky]

My friend  Mike who installed the V-caps in my VK60 has built the Grounded Grid preamp before and he told me that it sounded great ! thanks....WCW III

[richidoo]

OK, this POS is driving me nuts. I replaced 2 more caps today, left channel still hisses. I'm taking it to a pro (Sol) to find the hiss with a scope and fix the damn thing.

[miklorsmith]

Sorry Rich, that sounds very frustrating, especially since it sounds like an excellent performer when working right.

[richidoo]

Sol checked out the preamp, it is fine. Nothing wrong with it. Normal amount of hiss for a low priced tube preamp. The problem I have is just too much gain. The pre is 20dB, plus 30dB for my tube amps and a really hot source. It all adds up to volume control barely cracked, while 20dB gain on the hiss remains unattenuated. I had the same problem listening to the SB3 direct into NuForce amps on a high sensitivity speaker. The noise just adds up.

20dB gain is just too much for a modern preamp with most sources making 2V. 30dB is too much for power amps too, but they are extremely quiet, so it is not such a problem.  Transcendent Sound amplifiers are all only 20dB gain, so the GG is naturally a perfect match for them, giving a total of 40dB. Mine adds up to 52dB, 12dB or 4X higher. WEEZ used to rail about this, wasn't I paying attention? That's why I got modded minimax, only 9dB, perfect match to Snappers.

I have recently been using a ss amp with gain trim knob on the front. I had it cranked up to max, adding another 6dB to the already high nominal gain. Cranking it down to min removes all the noticable hiss from the GG, and allows VC to touch noon.

Padding the output would make the pre more compatible with my amps. I might do that.

So another richidoo saga made of foofoo dust finds its resolution on the full moon. Stay tuned for the next one!

[Carlman]

As long as the adventures start on a new moon, all will work out well.

[richidoo]

Swapped in VishayMKT polyester film output caps for the stock Solen MKP film caps today. What a huge difference in clarity. Detail, tone, space are all improved a lot. I think some vintage or EE tubes would really bring it alive.

[Carlman]

Uh oh... time for another listen?  I've gotten the system tuned-in a bit better now.. and sounds pretty good..  Let me know a good day and we'll re-analyze the changes.
If you want to do a little G2G, I'd be game for that also.

BTW, I got the TT and phono pre setup also.  It's all sounding very good. 
I just need 1 6922 tube for my DAC to complete things... something alive w/ a little warmth and not too bright. 
-C

[miklorsmith]

So, is this a practice unit to determine what parts you're going to include when you build the "real" GG?  

Carl - are you looking for advice on 6922s?  I've been rolling a fair number of them lately in two preamps . . .

[richidoo]

Carl, that sounds good. Above comments were after only 5 minutes of playtime, now a couple hours later even better. Solens were really holding it back. Funny thing these Vishays are even cheaper. Check to see if your phono preamp has the EE 12AU7s, if so, then we can put 3 of them into this GG to see what it can really do.

Den, you have some extra EE 12AU7s to sell? Thanks

Mikey, I recommended mid-1970's Matsushita 6922 to Carl, I had them in the Cary and they were really great for low dollars. Have you ever tried those? I wish I kept them. The Cary buyer sold it again after 2 weeks, along with the nice tubes.    Live and learn, "Save the tubes" I need a tea-shirt for that.

I'm more excited about it now, looking forward to hearing a regulated PS and better parts, wire, connectors, etc.  No I don't want to practice on this one, I'm just fixin it up for sale.

[mgalusha]

The caps make an amazing difference on the GG. Even the el cheapo Xicon's smoke the Solen IMO. Glad it's finally behaving for you Rich.

[Response Audio]

Hello richidoo
 Curious where you ended up with the GG preamp you were having troubles with. I won't go any further right now as it has been 4 months since the last post. If you still have it and it's still noisy, let me know as I may have some recommendations.

[richidoo]

Thanks Bill!!

I have been using it a lot lately with stereofool's ARvt100. It makes a nice combination. Carl used it with MC402 while his preamp was being upgraded. The pre is only noisy when the gain of the power amp is too high, like 30dB or more. Originally I was using it with 31dB Snappers, and a 40dB AudioSource SS amp. It is designed for use with Transcendent's own 20dB gain amps. Even with standard 26dB gain power amps it works good, with only a small amount of hiss, typical of low priced tube preamp. I would be very interested in hearing your suggestions about improving it further.

I found this article recently.  He upgraded VC, source selector, wiring and output caps. The kit is a good value for the money, but the design is limited by high gain and the noticeable stuffiness of feedback. I assume not much can be done about that. Reducing feedback would only increase the gain. The stuffiness is mild compared to a solid state amp. Music gets thicker but survives intact, unlike high feedback SS amps. It is awesome on bluesy funky music where the thickness is welcome.

I'm gonna build Aikido and if that's better, byebye GG. Meantime it is a good workhorse. I know it will break even when I sell, that's a nice feeling.

[richidoo]

I replaced the Vishay Roederstein MKT-1822 caps with Jentzen Superior Z-Caps in for coupling output caps. Wow what a difference, the preamp has really come alive, and they only have 30 minutes on them. These are nice caps at a decent price, at least in comparison to some other exotics. I had no idea this preamp was capable of this performance level. The Vishays were a big improvement over the stock Solens. Thanks to shep and mgalusha for the recommending Jantzen.   I have been procrastinating upgrading the speaker CO caps because I thought I needed fancier caps, but these are good enough for my needs.