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Analog Paper^2 Discussion and Appreciation Thread. - Page 136
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i used green and blue to visually separate the one manufacturer sets (df91 - dl92, green) from the dl92, dl91, 1s4 and other special tubes departement, but in fact the box would need nearly twise the size for that while providing some space for new tubes.
Edited by GermanGuy - 9/7/13 at 7:37am
Very IMPRESSIVE. But... isn't a problem to get rid of all the original cardbord boxes ?
on a very less impressive skill scale, I have modified the RFT DF97 that I received and.... listening to them now. I will follow Ian advice and don't comment before I reach 10 hours... :-)
As for me, Well, while the amp has been away I have been researching different materials suitable for supporting tube amps and have come across many camps and schools of thought on the subject so I have come up with something that damps but also provides firm, stable support and transfers mechanical and electrical energy to heat which seems to be the best solution for tubes to operate quietly.. I will find out on Monday!
So the picture below shows (from base to top) a Thick slab of granite Four large blobs of blu-tac on to which is placed a thick slab of marine plywood covered in a vinyl wrap. On to that are the three oak cones. Now, the Oak cones are a sandwich. Blu-tac between the plywood and cone, a thin layer of blu-tac spread across the wide base of the cone (which is the top in this application) and then a thin layer of cork.
Cork apparently is a great converter of energy into heat so that sits next to the amp. That energy goes through the visco-elastic of the blu-tac to the hard oak cone which then goes through another layer of blu-tac to the vinyl wrapped plywood (the vinyl wrap damps as well) this then goes through yet more blu-tac to the granite base with its random structure which will efficiently dissipate what little electrical or mechanical energy is left!
A bit Heath Robinson I agree and the whole thing may not work, I will find out on Monday!
Here is a picture of it all!
btw, i started listening to a pure mullard df91 - dl92 combo today.
and btw too, i yesterday ordered
- the vu meters,
- gold plated cinch connectors,
- gold plated loudspeaker connectors,
- a pcb board containing the logic to connect the vu meters to the signals (nothing special, but when i can buy something, why not saving some time),
- two meters of thin mu metal (permalloy, 40mm and 50mm wide) for the sub chassis and some shielding,
and also sent shikada-san an email to ask for an offer and if he is willing to sell me
- a second internal pcb tube power supply board
- a second tube bias battery pack
- a second capacitor labeled '.221.'
- a second car charger to extract the charger pcb board needed for the second battery pack i already ordered
and asked if i can get my custom tu-05 case long version without holes also in a 3 cm wider version.
Edited by GermanGuy - 9/7/13 at 8:39am
Interesting since I myself am Waiting for my mullard DF91 to come and I already have some Mullard DL92 ( 3S4 - from 1959) :-)
Question: have you tested the Mulard DF96 ? Are they any good ? Indeed I have 3 of them !
And good luck for your BIG project. I am sure those Vu-meters will be georgeous.
On my side, I will very soon make my first "small" modification: Replacing some internal cables with better quality cables, and replacing the jack 1/8 on the front by a XLR on the back (with ground Left & Right coming from the transformer no long connected together :-). Plus solding pins 4 & 5 from the 2 Voltage Stage tube connectors.
Edited by bmichels - 9/7/13 at 9:59am
i have no mullard df96.
and happily awaiting the first pictures of your mod. which cables have you planned to use?
tommorow (after some research if that makes sense) i will gold plate a piece of this pure silver 0.75 mm axmann axiom III wire and isolate it with teflon tape and shrink-on tube to evaluate if it could be used recableling my amp.
I will use the same cable that has been used to re-wire my TH-900 so that it will be the same cable from the transformer to the hear cups ;-). It is copper OCC CRYOGENISE cable coming from this french guy.
1 QUESTION for GermanGuy : are there other " strategic" cabling, besides the one going from to transformer output to the headphone plug, that will be worth recalling with better wires ? Which one have you recabled ?
Edited by bmichels - 9/7/13 at 1:33pm
In the mean time I am trying to make the weekend go fast so have been out today flying to take my mind of waiting for the Amp!
Ian, I hope your weekend goes quickly. I totally feel your pain on the long wait for the return of your amp. Please post details & pics on your isolation project. I am very interested. And not just the Nutty Europeans, but the 'Nutty European Professors'!!