• Disclaimer: This Vendor's Forum is a paid-for commercial area. Unlike the rest of diyAudio, the Vendor has complete control of what may or may not be posted in this forum. If you wish to discuss technical matters outside the bounds of what is permitted by the Vendor, please use the non-commercial areas of diyAudio to do so.

The AKSA ' 'TLP' - a great solution to a digital issue! :-))

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
The 'TLP' is a tube buffer which Hugh produced before he developed his GK-1 preamp ... which then led on to the GK-2, which I have. So it's a product from long ago ... which languished, after the GK-1 came out. :(

Now, I have just dipped my toe into the digital waters ... replacing the 3-way analogue active XOs I've been using with my Maggies for 15 years with a miniDSP unit (10x10Hd). I did this because I added a pair of subs to my Maggies, so:
1. I needed a 4-way XO, and
2. I needed to use DSP to delay my Maggies, to line up with the subs which are about 1.3m further away from my ears.

As a result, I have just bought 2x TLP kits! :cool:

Now, my system currently is: sources --> GK-2 --> miniDSP --> power amps.

The beauty of the GK-2 is that it has 2 outputs:
1. the ss (sub) output. (This bypasses the unity-gain tube output stage of the GK-1/GK-2.)
2. the tube output.

If you are running active speakers, it is a well-known fact that you should feed your woofers from the 'sub out' and your tweeters (& mids) from the 'tube out'. The reason is:
* ss out gives better definition of the leading edge of bass transients (than the tube does), and
* tube output gives a more entrancing delivery of mids & HFs than the sub out does.

So currently:
* my sub out feeds subs + bass panels, and
* my tube out feeds mid panels + ribbons.

This is fine ... but as the next component in the signal chain is my miniDSP unit, it is possible I don't hear the full beauty of the 'tube out' coming from the speakers that I did when I had analogue active XOs? :(

So I am going to re-arrange my component chain and remove the GK-2. This is not a simple exercise as I need to have:
* source selection, and
* volume control.

My component chain now becomes:
* phono stage ---> ADC
* 4x digital sources (phono ADC / CDP / DAB+ tuner / Foxtel box) to digital source selector (Audio Authority 1177A-1)
* output from 1177A-1 ---> miniDSP (digital input)
* 8x RCA outputs from the miniDSP 10x10HD ---> an 8-channel volume control (DIY "Relaixed", out of Holland)
* 8-channel output from the Relaixed volume control --->
-- 4 channels of TLP, for mids & ribbons ---> power amps
-- 4 channels direct, for subs & bass panels ---> power amps.

So, this way, I should really be able to hear the 'tubeyness' of the TLP, as it is directly feeding the mid & ribbon power amps ... in contrast to my current situation where, really, I am "listening to the sound of" the miniDSP output DACs (which cannot be very good, given the price of the miniDSP!).

I will report back when it's all come together! :cheers:

Andy
 
Pic is here ... the space in the middle is for my 2 RelaiXed PCBs - which give me an 8-channel, digitally-controlled analogue volume control.

These 4 channels are for mids & ribbons - they are fed by one of the Relaixed boards. Subs & bass panels are fed directly from the other 4-channel Relaixed board.

Andy
 

Attachments

  • RelaiXed-TLP 02.jpg
    RelaiXed-TLP 02.jpg
    861.8 KB · Views: 990
I am curious to learn your impressions.

Well, it's taken 14 months - not 6! :( - but I finally listened to the new setup, yesterday! :D

First impressions are:

* it sounds great! :)
* but I can hear some hash on the mids & ribbons - not hearable at the listening position but certainly noticable when your ear is right at the driver. I was afraid this might happen so I think I know how to solve this problem. (Put an earthed shield over the 6v & 15v feeds from the power transformers that run close to the I/O wiring, on the other side of the steel divider between transformers and signal boards).

Monday is the "real test" - when my panel of 'golden ears' (including Hugh) comes round for a listen. :)

Pics attached.

Andy
 

Attachments

  • RelaiXed-TLP Front.JPG
    RelaiXed-TLP Front.JPG
    436 KB · Views: 801
  • RelaiXed-TLP Back.jpg
    RelaiXed-TLP Back.jpg
    486.9 KB · Views: 765
  • RelaiXed-TLP Top.jpg
    RelaiXed-TLP Top.jpg
    818 KB · Views: 755
6ES8 is a variable mu tube.

As a cathode follower this is not usually a problem. ECC189 has the same specifications.

Its a bit like the cathode follower of choice for those who cannot justify the cost of 6922 or 5687.

Makes perfect sense IMO, and also IME having had such with a pre stage to Hugh's AKSA.
 
HK,

I thought you died in South Africa in an air crash? Good to see you are here!
A variable mu tube makes a nice cathode follower and slightly increases the H2 and H3, what I was wanting in my preamp. The 6922 and 5687 are 30% and 100% more plate current, not needed here. And the 5687 runs very hot, with a 900mA 6.3Vac filament compared to 365mA of the 6922 and 6ES8. Very hot tube pins create oxidisation and reduce tube life, try a 6C33 for this issue......

HD
 
I am curious to learn your impressions.

Further to my previous post regarding how I thought my new setup sounded - which:
* uses a 96kHz A2D to digitise my phono stage
* removes my GK-2
* feeds the digitised phono signal into the digital input of my miniDSP 10x10HD (whereas the GK-2 fed the analogue inputs)
* has a 'RelaiXed' 8-channel volume control after the miniDSP, with TLPs on the mids and ribbons

. . . I'm happy to report that yesterday's listening panel (including Hugh) unanimously thought the new setup delivered better sound than before. So it would seem that having the tubes at the end of the sound chain, after the miniDSP (instead of before), allows the full beauty of the tubes to shine through. :)

So I'm delighted with my purchase of 2 of Hugh's TLPs! :D


Andy
 
Andy,

Thank you for a great afternoon listening session. I was very impressed with your beautifully built amps, preamps, MiniDSP, and enhanced Maggies. Your system is remarkable and incredibly resolving without listener fatigue. Difficult to do, even with A to D off your lovely turntable!

Any Melbournites - Andy's system is arguably one of the best I have ever heard and I strongly commend it to you. Contact him; he's very gracious and will give you a good listening. He is in Richmond.

Thanks again, Andy!

Hugh
 
Uncle Hugh,

Thanks for this nice sounding preamp. This is my first tube project, learned a lot , did not know the B+ voltage fall so much when heaters are applied with the small back to back transformers!:) Well so we all learn. Sinus and square wave looks great up to a little over 100 kHz then there comes a little oscillation. It sounds very good on my small Pioneer test amp with AR9S speakers. I did use DC for the heaters elevated to B+. Now to put it in a nice box.:)
 

Attachments

  • IMG_20200320_185211.jpg
    IMG_20200320_185211.jpg
    1 MB · Views: 286
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.